Dissertations / Theses: 'Optical fiber network'

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Okonkwo, Igweani Uchenna Titus. "Optical fiber transmission systems for in-door next generation broadband access network." Thesis, Brunel University, 2014. http://bura.brunel.ac.uk/handle/2438/10539.

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This thesis investigates the generation and radio-over-fibre (RoF) transport of unlicensed 60 GHz millimetre-wave (mm-wave) frequency band. The investigated benefits of transmission schemes applicable for the mm-wave generation include optical carrier suppression (OCS), optical frequency multiplication (OFM) and remote heterodyne detection (RHD). For the in-door cabling of the mm-wave transmission, a low-cost polymer optical fibre (POF) along with bend-insensitive single mode fibre (BI-SMF) has been investigated for short-range networks. Transporting mm-wave generated signals over POF and BI-SMF cables based on OCS scheme showed results with the highest spectral efficiency and least inter-symbol interference over a 2.5 Gbit/s data delivery. Based on this thesis analysis, OCS simulation of POF showed the most reliable power penalty performance and receiver sensitivity at 30-m whilst the BI-SMF fiber produced equal observations at 150-m and more. In observing the free space links of delivering the RoF signal, the attenuation on the received signal power for both POF and BI-SMF was insignificant but expected, as the simulation assumed complete and total collimation of the light beams onto the aperture of the photodetector. OCS scheme for mm-wave generation and transport was explored based on the cost effectiveness of using one external modulator compared to other generation schemes that utilised more than one external modulator. OFM scheme was simulated to transport LTE and Wi-Fi signals along with 60 GHz RF band through both SMF and MMF-POF/BI-SMF cables. OFM transport scheme produced the highest attenuation on LTE, Wi-Fi and mm-wave signals carrying 100 Mbit/s data as simulated POF lengths increased. The best performance POF length was observed at 10-m. The application of offset launch technique at the coupling of SMF and POF showed insignificant improvement on signal bandwidth. The free space OFM transmission also demonstrated negligible change to the received signal power. This reinforces the attributes of deploying OWC system in an in-door environment. In other investigation, the simulated successful delivery of mm-wave signal using RHD scheme modulated and transported 10 Gbit/s data signal over POF and BI-SMF cables. Additional observed unrecorded result also showed BI-SMF cable maintained a 2% reduction of received power for 450-m fiber cable from 150-m. The attributes to RHD includes its low operating power system application and delivery of localised 60 GHz signal for uplink RoF transmission. The conceptualised design of Gigabit data delivery for indoor customer applications either through POF or BI-SMF cable, transporting various wireless channels has been presented in this thesis for the design of a robust next generation Broadband access network to reinforce the fiber-inside-the-home (FiTH) deployment.

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Tariq, Sana. "Inside all-optical networks /." Online version of thesis, 2009. http://hdl.handle.net/1850/10960.

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Quintana, Joel. "Hybrid optical network using incoherent optical code division multiple access via optical delay lines." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2009. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.

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Angeh, Wolfgang Ondua. "Design and performance analysis of a survivable metropolitan area fiber optic communication network." Master's thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-02022010-020030/.

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Wang, Evan Y. (Ye-Wen). "Traffic control in a multichannel optical fiber communication network." Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/14716.

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Cindoğlu, Beylem. "User Research and Development on Optical Fiber Network Installations." Thesis, KTH, Maskinkonstruktion (Inst.), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-198178.

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Detta examensarbete är ett projekt som genomförs på Infinera i Stockholm, Sverige. Projektet använder tjänsten designmetodik tillsammans med användarcentrerad design. Syftet med projektet är att undersöka och förbättra det dagliga arbetslivet för installatörer av fiberoptiska nät. Den aktuella tjänsten följer ett systemdrivet perspektiv. Detta projekt undersöker olika sätt att ändra ett systemdrivet perspektiv till ett användarcentrerat designperspektiv. Tjänstedesignmetoder används för att undersöka serviceprocessen och att samla insikter. Projektet inleds med en förberedelsefas, följt av loop 1 och 2. Förberedelsefasen används för att få en djupare förståelse för fiberoptiska nät. Loop 1 och loop 2 inkluderar metoder såsom skuggning, en dag i livet, intervjuer och kartor över kunders resor. I dessa loop faser ingår interaktion med kund, analys av kundens interaktioner samt idealisering från dessa analyser och begrepp. Fem huvudproblem identifieras i processen. Dessa delas in i två kategorier som processrelaterade problem och användarrelaterade problem. Resultaten visar att den främsta orsaken bakom processproblem är brist på kommunikation mellan avdelningar inom företaget. Dessa problem är bland annat projektledares beteckning, bristande redovisning av arbete och överlämnandet mellan försäljningsavdelningen och tekniker. Överlämnandet mellan försäljningsavdelningen och tekniker väljs som ett nästa steg för fördjupning. Webbapplikationer formas som ett koncept för att lösa det problem som väljs. Projektet avslutas med förslag på webbapplikationer avseende lösningar för utvalda problem. Problemen identifieras relaterat till processen. Försäljningen till tjänsten överlämnande väljs för ytterligare förbättringar. Det genererade konceptet på detta problem förbättras och presenteras för företaget.
This thesis is a project that is conducted at Infinera located at Stockholm, Sweden. The project uses service design methodology alongside with user-centered design. The aim of the project isto examine and improve every day work lives of implementers of fiber optic networks. The current service is following a system-driven perspective. This project will examine ways to change this into a user-centered design perspective. Service design methods were used to investigate the service process and to gather insights. The project started with an initial preparation phase, followed by loop 1 and 2. Preparation phase was used to get a deeper understanding on fiber optic networks. Loop 1 and loop 2 included methods such as shadowing, a day in life, interviews and customer journey maps. These loop phases included interactions with the customers, the analysis of these interactions, ideation from these analysis and conceptualization. Five main problems were identified in the process. These were grouped into two as process related problems and user experience related problems. It is found out that the main reason behind process problems was lack of communication between departments in the company. These problems were project manager designation, lack of statement of work and the handover between sales department and technicians. The handover between sales department and technicians were selected as a next step to go on. Web applications were shaped as a concept to solve the problem that was selected. The project was finalized with suggestions on webapplications regarding the solutions of selected problems. The problems were identified related to the process. Sales to service handover was selected for further improvements. The generated concept on this problem was improved and presented to the company.

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Rotich, Enoch Kirwa. "Fibre optic network supporting high speed transmission in the square kilometre array, South Africa." Thesis, Nelson Mandela Metropolitan University, 2015. http://hdl.handle.net/10948/6552.

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This thesis provides in-depth information on the high speed optical transport requirements for the Square Kilometre Array. The stringent data rates as well as timing and synchronization requirements are dealt with respect to the optical fibre technology. Regarding the data transport, we draw a clear comparison between a typical telecommunication access network and a telescope network. Invoking simulations and experiments on the field and laboratory test bed, we successfully implement a suitable telescope network using vertical cavity surface emitting laser (VCSEL) technology. Polarization effects on the KAT-7 telescope network, an operational prototype for the SKA is studied so as to estimate the expected effect in the MeerKAT telescope with transmission distances _ 12 km. The study further relates the obtained values to the expected impact on the distribution of the time and frequency reference in the MeerKAT array. Clock stability depends on the differential group delay (DGD) and polarization stability. On a 10:25 km link that includes the riser cable a DGD of 62:1 fs was attained. This corresponds to a polarization mode dispersion (PMD) coefficient of 19:4 fs=km1=2. This is a low PMD value considering telecommunication network. The PMD value is within the allowed budget in the telescope network. However, this may not be the case at longer baselines extending to over 1000 km as expected in SKA 2. The fibre's deployment contribution to the DGD is measured by comparing the deployed fibre to the undeployed of equal lengths. On the 10:25 km deployed single mode fibre, the maximum and mean DGDs measured were 217:7 fs and 84:8 fs respectively. The undeployed fibre of similar type and equal length, gave a maximum and minimum DGDs of 58:6 fs and 36:3 fs respectively. The deployment is seen to increase the maximum and minimum DGDs by factors of 3.7 and 2.3 respectively. This implies that fibre deployment is very critical in ensuring the birefringence is minimized. Polarization fluctuation recorded a maximum of 180o during the 15 hour real time astronomer use of the antenna. To ascertain the contribution of the riser cable, state of polarization (SOP) of the buried section of the single mode fibre in the link was established. A maximum SOP change of 14o over 15 hour monitoring was measured. From the stability realized on the buried section of the fibre, the change in polarization is contributed by the riser cable. The fluctuation in polarization can cause the phase of a clock signal to drift between the birefringent axes by an equal amount corresponding to DGD. We experimentally demonstrate how polarization stabilization can be attained using the polarization maintaining fibre. We also demonstrate the applicability of VCSEL technology in the SKA unidirectional data flow especially for shorter baselines < 100 km. The VCSEL is a low cost light source with attractive advantages such as low power consumption, high speed capabilities and wavelength tuneability. This work entails the use of traditional amplitude modulation commonly known as non-return-to-zero (NRZ) on-off keying (OOK) because of its simplicity and cost. For the MeerKAT typical distances, we show that even in a worst case scenario, the use of VCSEL on different fibres in MeerKAT distance is achievable. Using the impairment reduction approach, we successfully manage to achieve transmission distance beyond MeerKAT. Several in-line dispersion compensation mechanisms in telecommunication have been successfully employed. The work focused on the use of negative dispersion fibre to mitigate the chromatic dispersion effects in the optical fibre. The inverse dispersion fibre (IDF) is proposed for compensation in the conventional zero dispersion wavelength fibres, G.652 that are used at the third window. Similarly, the chromatic dispersion compensation of non-zero dispersion shifted fibre (NZDSF) is experimentally demonstrated using negative dispersion submarine reduced slope (SRS), G. 655 (-). With dispersion management, we demonstrate how transmissions beyond MeerKAT baselines can be achieved error free. A systematic investigation of the use of distributed Raman amplification to overcome the attenuation losses is provided. High on-off gains of up to 15 dB, 8 dB and 5 dB for bidirectional, forward and backward pumping respectively is achieved on a 25 km Raman optimized NZDSF-Reach fibre. Combined dispersion mitigation technique and low noise distributed Raman amplification, up to about 80 km transmission was achieved on a 4:25 Gbps modulated VCSEL using a single pump. Using bidirectional pumping, more than 100 km of transmission was achieved error free. The high gains enhance the VCSEL transmission distance. We further suggest a novel way of using the Raman pump to distribute the clock signal while amplifying the data signal streaming the astronomical data from the remote placed telescope receivers. In summary, the work presented in this thesis has demonstrated the potential use of VCSEL technology for data collection in the telescope array. We have studied the optical effects and mitigation so as to improve the clock and data transmission. This work is relevant and valuable in providing SKA with VCSELs, an option for extremely high network performance at reasonable costs.

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Ansari, Ashlaghi Aria. "100 GBPS Orthogonal Frequency Division Multiplexing optical fiber communication network." Thesis, California State University, Long Beach, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1604879.

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Optical fiber communication has emerged as a high potential substitute for communication methods such as twisted pair and coaxial wire. The main advantage of optical fiber over previous methods is to have higher capacity of data rate transmission. The conventional types of modulation and demodulation technique, which have been used through optical fiber communication system are Wavelength Division Multiplexing (WDM) technique and Dense Wavelength Division Multiplexing (DWDM) technique so far.

In this thesis, the Orthogonal Frequency Division Multiplexing (OFDM) is applied through the modulation and demodulation parts due to some advantages over WDM and DWDM to reach to 100 Gbps data transmission. The main advantage of OFDM-optical fiber is that it only needs one optical source to modulate and one optical source to demodulate the signals at transmitter side and receiver side, which results in a reduction of the cost of the system. Also, by using the OFDM, the chromatic dispersion can be eliminated or decreased.

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Darweesh, Jamal. "Quantization of Neural Network Equalizers in Optical Fiber Transmission Experiments." Electronic Thesis or Diss., Institut polytechnique de Paris, 2023. http://www.theses.fr/2023IPPAT025.

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L'avènement de la détection cohérente a ouvert la voie à la compensation des effets liés à la propagation dans les fibres optiques en utilisant le traitement numérique du signal (”DSP”). Alors que les effets linéaires, tels que la dispersion chromatique et la dispersion modale de polarisation, peuvent être compensées efficacement, la compensation des distorsions non linéaires reste aujourd'hui un défi compte-tenu des complexités d'implémentation. Dans ce travail, nous considérons les réseaux de neurones (”NN”) pour l'égalisation dans la trans- mission par fibre optique à double polarisation. Par rapport aux égaliseurs conventionnels tels que la rétropropagation numérique (”DBP”), les NN ne nécessitent pas d'informations sur l' état du canal, et peuvent atténuer les dégradations du signal avec une moindre complexité. Nous proposons un certain nombre d'algorithmes de quantification ”post-training” et ”training-aware” pour représenter les poids et les activations du NN en quelques bits, ceci afin de réduire la complexité de calcul, l'espace mémoire et la consommation d'énergie du DSP. Une analyse de performance et de complexité montrent que les algorithmes proposes surpassent les algorithmes d'égalisation linéaire et DBP dans plusieurs expériences de transmission. Cette thèse est réalisée dans le cadre du projet H2020 MSCA-ITN-EID REAL-NET, financée par la Commission Européenne (en collaboration avec le partenaire industriel, Infinera Corporation, en Allemagne et au Portugal)
The advent of the coherent detection paved the away for the compensation of the fibertransmission effects in the electrical domain using the digital signal processing (DSP).While the chromatic and polarization mode dispersion can be efficiently compensated withDSP, the compensation of the nonlinear distortions remains challenging.In this work, we consider neural networks (NNs) for nonlinearity mitigation in dualpolarization optical fiber transmission. Compared to the digital back-propagation (DBP),NNs do not require the fiber link parameters, and may mitigate the impairments withlower complexity.We propose two low-complexity NN equalizers: a convolutional-dense and an LSTM-dense model, placed at the end of the linear DSP to compensate the nonlinearities. Theseequalizers are evaluated in the context of three dual-polarization transmission experiments:a 9x50km true-wave classic fiber link, a 9x110km standard single-mode fiber link, and a17x70km LEAF fiber link. It is shown that the proposed NNs and DBP achieve about thesame Q-factors, both outperforming the linear DSP.We use quantization in order to reduce the computational complexity, storage sizeand energy consumption of the NN equalizers. We compare a number of post-trainingquantization (PTQ) and training-aware quantization (TAQ) algorithms for casting theweights and activations of the NN in few bits. For quantization above 5 bits, we showthat TAQ with straight-through estimation (STE) outperforms PTQ, since it mitigatesthe quantization noise during the training to some extent. For a Q-factor drop of less than0.5 dB compared to the unquantized NN, the storage and computational complexity of theNN can be typically reduced by over 90%. However, there is a bit width cut-off value ofaround 5 bits below which TAQ fails to outperform the linear DSP. This is because, theapproximation of the derivative of the quantizer in the STE is not sufficiently accurate atlow bit widths. Further, the proposed low-complexity models are not overparameterized,so that the quantization noise can be mitigated during the training at low bit widths. Itis shown that the quantization of the activations has a greater impact on the performancecompared to the quantization of the weights.Finally, we study extreme quantization of the NN equalizers below 5 bits. For thiscase, we propose three novel algorithms: successive PTQ (SPTQ), alpha-blending (AB)and successive AB (SAB) which is a hybrid algorithm that combines the SPTQ with AB.These algorithms are iterative, and incorporate ideas from PTQ and TAQ. We demonstrateiiithat the weights of the NN can be quantized up to one bit, if the activations are notquantized. Further, it is shown that both weights and activations can be quantized at 2-3bits, while still notably outperforming the linear equalization. Furthermore, we quantifythe impact of the quantization noise arising separately from the weights and activationson the Q-factor performance of the model. The results demonstrate for the first time thatlow-complexity binary NNs can mitigate nonlinearities in optical fiber communication.This PhD thesis is in the frame of a European Union's Horizon 2020 MSCA-ITN-EID REAL-NET project, grant agreement no. 813144, in collaboration with Infinera inGermany and Portugal

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Chu, Guang Yong. "Photonic devices for next generation fiber-to-the-home access network." Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/386564.

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It would be unaffordable if the WDM-PON technologies were directly applied for massive deployment. Hence, the potential WDM-PON is to be integrated and improved in order to adapt it for NGPON and the future 5G. The UDWDM-PON can be considered as an ultimate solution for the next-generation access network capable of providing unlimited bandwidth for each user, thanks to the coherent detection. Plenty of scientists have believed that it is crucial to increase the operating speed and maximum reach of WDM-PON, while it has no sense if people achieve them without a ordable cost. In order to apply them cost-effciently, the system should require colorless ONUs and bidirectional systems. It is desired that the whole system use modulators on a low bias consumption, even limit the number of amplifiers. However, for bidirectional transmission the backscattering effects would limit the performance if we want to reuse the carrier from OLT. So, we should design a method to separate the wavelength between upstream and downstream. The traditional UDWDM-PON uses 2 laser at ONU, in this thesis, the single-DFB based ONUs are presented with integrated devices. What is the most plausible configuration? The photonic devices such as RSOA, DEML, FML with advanced configurations are presented in this thesis with different applications. The proposed thesis includes these parts: key devices for WDM-PON and the chirp parameters of these integrated photonic devices are measured, the polarization independent RSOA with different applications is also included, demonstration of dual output DEML with bidirectional coherent UDWDM-PON transmission, mitigating residual AM of DEML for phase modulation, and fast tuning for the UDWDM channel via FML are described.
Por sus altos requerimientos técnicos, sería inasumible aplicar las tecnologías WDM-PON directamente para el despliegue masivo de Fiber-to-the-Home de nueva generación. Por lo tanto, el potencial se WDM-PON se debe integrar y mejorar con el fin de adaptarlo para NGPON y el futuro 5G. Hoy dia, operadores, usuarios y científicos, ven crucial augmentar la velocitat de funcionament y el alcance de las redes de acceso PON, si bien no tiene sentido conseguirlo con un coste inasequible. El UDWDM-PON puede considerarse como una solución definitiva para la red de acceso de próxima generación, capaz de proporcionar ancho de banda ilimitado para cada usuario, gracias a la detección coherente, por lo que en esta tesis se aborda su realización con un coste e integración prácticos. Con el fin de aplicarlos de manera rentable, el sistema debería exigir a las ONU que sean idénticas, si láseres preseleccionados o incoloros, y ser bidireccionales. Se desea que el conjunto de moduladores del sistema tengan en un bajo consumo, e incluso limitar el número de amplificadores. Sin embargo, para la transmisión bidireccional los efectos de retrodispersión limitarían el rendimiento si queremos volver a utilizar la portadora generada en la OLT. Por lo tanto, debemos diseñar un método para separar la longitud de onda en las transmisiones de bajada y de retorno del usuario a la central. El tradicional UDWDM-PON utiliza 2 láseres en la ONU; en esta tesis, las ONUs usan dispositivos integrados basados en un sólo DFB. ¿Cuál es la configuración más plausible? Los dispositivos fotónicos como RSOA, DEML, FML con configuraciones avanzadas se presentan en esta tesis con diferentes aplicaciones, que resuelven distintos problemas técnicos. La tesis incluye las siguientes partes: análisis y medida de dispositivos fotónicos clave para WDM-PON con modulación de fase, la independencia a la polarización de RSOA con diferentes aplicaciones, demostración de DEML con doble salida para transmisión bidireccional coherente UDWDM-PON, mitigación de AM residual de DEML para la modulación de fase, y la sintonía rápida de canal de UDWDM a través de FML.

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Ganti, Sudhakar N. M. "Access protocols and network architectures for very high-speed optical fiber local area networks." Thesis, University of Ottawa (Canada), 1993. http://hdl.handle.net/10393/6917.

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The single mode optical fiber possesses an enormous bandwidth of more than 30 THz in the low-loss optical region of 1.3 $\mu$m and 1.5 $\mu$m. Through Wavelength Division Multiplexing (WDM), the optical fiber bandwidth can be divided into a set of high-speed channels, where each channnel is assigned its own unique wavelength. An M x M passive optical star coupler is a simple broadcast medium, in which light energy incident at any input is uniformly coupled (or distributed) to all the outputs. Thus, a passive star along with the WDM channels can be used to configure a Local Area Network (LAN). In this LAN, users require tunable devices to access a complete or a partial set of the WDM channels. Due to these multiple channels, many concurrent packet transmissions corresponding to different user pairs are possible and thus the total system throughput can be much higher than the data rates of each individual channel. To fairly arbitrate the data channels among the users, media access protocols are needed. Depending upon the number of data channels and the number of users, two possible situations arise. In the first case, the number of users is much larger than the number of data channels and in the second, the number of users equals to the the number of channels. In both cases, data channel contention may arise if multiple users access the same given channel and must be resolved. This thesis proposes media access protocols for passive optical star networks. All the proposed protocols are slotted in nature, i.e., the time axis on each channel is divided into slots. The well known Slotted-ALOHA and Reservation ALOHA protocols are extended to the multi channel network environment. The thesis also proposes switching protocols (equal number of channels and users), contention-based reservation protocols for this network architecture. To interconnect these star networks, a multi-control channel protocol is also proposed along with two interconnecting techniques. Since there are multiple data channels, the data packets on different channels may be destined to the same user. However, if the user is equipped with only one receiver, the user can receive only one packet and ignores others. This is called a 'receiver collision' and the thesis also studies the effect of these receiver collisions on the data channels. Two network architectures, one for a packet circulating ring network and the other for a circuit switched application are described. Finally, the thesis studies some implementation considerations for these protocols.

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Ee, Chai Chuan. "The feasibility study of implementing a fiber optic local area network in software metrics laboratory in Ingersoll 158." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Mar%5FEe.pdf.

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Thesis (M.S. in Information Technology Management)--Naval Postgraduate School, March 2004.
Thesis advisor(s): Norman F. Schneidewind. Includes bibliographical references (p. 51). Also available online.

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Terra, Osama [Verfasser]. "Dissemination of ultra-stable optical frequencies over commercial fiber network / Osama Terra." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover, 2010. http://d-nb.info/1010837621/34.

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Schrenk, Bernhard. "Characterization and design of multifunction photonic devices for next-generation fiber-to-the-home optical network units." Doctoral thesis, Universitat Politècnica de Catalunya, 2011. http://hdl.handle.net/10803/22676.

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El estudio e investigación en el campo de las redes ópticas de acceso han sido fomentadas en años recientes debido a la continua migración de Servicios multimedia que son ofrecidos a través de Internet. Aunque los dispositivos utilizados para implementar Fiber-to-the-Home (fibra a casa), que reemplazan las soluciones tradicionales basadas en cable de cobre, están basadas aún en micro-óptica, se puede prever una evolución hacia integración fotónica. Todavía queda la pregunta acerca de los diseños necesarios para este paso importante de integración, que debe ser optimizado en términos del desempeño de transmisión, eficiencia energética y costo con el fin de lograr todos los requerimientos de las redes fotónicas de siguiente generación. Como elemento más crítico en las redes de acceso ópticas es el equipo en los clientes, este trabajo se centra en éste. Los temes cubiertos abarcan una gama amplia e incluyen: el reciclado de longitudes de onda para transmisión de datos en full-dúplex a través de una sola frecuencia óptica; la generación de formatos de modulación avanzados con moduladores semiconductores de bajo costo y factor pequeño de integración; soporte de amplificación óptica a través de técnicas de sembrado y el soporte de funcionalidades de capes superiores en la capa física. Después de la prueba principal de las técnicas propuestas, se resaltan los beneficios, impedimentos y caminos de reemplazo hacia sistemas fotónicos multifuncionales a través de casos de estudio. Por su parte, los diseños más representativos se profundizan más sobre todo por su posibilidad de ser integrados fotónicamente.
Optical access technology has experienced a boost in the last years, thanks to the continuously migrating multimedia services that are offered over the internet. Though the devices used for deploying Fiber-to-the-Home instead of traditional copper-based solutions are still based on micro-optics, an evolution towards photonic integration can be foreseen. What remains is the question about the exact designs for this important step of integration, which should be optimized in terms of transmission performance, energy efficiency and cost to address all requirements of next-generation photonic networks. As the most critical element in optical access, the customer premises equipment is in primary focus of this discussion. The covered topics span over a wide range and include wavelength recycling for full-duplex data transmission on a single optical frequency, the generation of advanced modulation formats with low-cost semiconductor modulators with small form factor, support for optical amplification by means of seeding techniques and the support of higher layer functionality at the physical layer. Next to the principal proof of the proposed techniques, the benefits, impediments and upgrade paths towards multifunctional photonic systems are highlighted in different case studies, while the most representative designs are further discussed in their capability of being photonically integrated.

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Hawkins, William Cory. "Evaluation of the Data Vortex Photonic All-Optical Path Interconnection Network for Next-Generation Supercomputers." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14519.

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Todays supercomputers employ the fastest processors incorporating the latest VLSI technology. Unfortunately, usable system performance is often limited by excessive interprocessor latency. To overcome this bottleneck, this thesis explores the use of all-optical path interconnection networks using a new topology defined by Coke Reed [31]. This work overcomes limitations of previous optical networks through a novel use of defection routing to minimize latency and allow more processors to collaborate on the same application and dataset. In this thesis research, the data vortex is formally characterized and tested for performance. Extra angles serve as virtual buffers to provide required system performance, even under asymmetric mode operation. The data vortex is compared to two well-known interconnection networks (omega and butterfly) using metrics of average latency and message acceptance rate. The data vortex is shown to outperform the comparison networks, with a 20-50% higher acceptance rate and comparable average latency. The impact of angle size is also studied, and a new, synchronous mode of operation is proposed where additional angles are added to increase the virtual buffering of the network. The tradeoff between virtual buffering and angle resolution backpressure is explored, and an optimal point is found at the 1:6 I/O to non-I/O (virtual buffering) angle ratio. The new mode and optimal angle count are used to form data vortex networks that perform as well as larger networks with fewer total nodes. Finally, hierarchical layering with data vortex clusters is proposed and compared to a single-level data vortex. In todays technology, similar performance is attained at high network communication locality loads (> 2/3), and a 19% latency reduction is obtained at the highest locality loads (> 95%) for current optical switching technology. For projected future technology, the clustered system is shown to yield up to a 55% reduction in latency for applications with 2/3 or better locality.

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Kostic, Igor Aleksandar. "Fiber-Based ATM Computer Network Performance and Survivability Issues under Soft Failure Conditions." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/34896.

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In this research a suspected "gray" area in computer network performance that might exist between the network's optimum performance and complete network failure was investigated. Changes in performance were studied as seen by the application layer of the network as attenuation was introduced at the physical layer of the network. The network performance was measured for four groups of tests running over TCP and UDP. Various scripts emulating different network applications were used. Ultimately the performance was evaluated at different optical power levels, based on throughput, transaction rate, response time, and lost data. Additionally, the bit error rate characterization of the attenuated optical fiber link was analyzed. Ultimately, performance of the fiber optic ATM-based computer network as seen by the user was correlated with optical power degradation introduced in the physical layer. A decrease in performance was found as attenuation was increased, even in the range of "normal" operating conditions. As expected, TCP, although not immune to soft failures, performed better than UDP. A description of the investigation, tests, scripts, methods and results are included.
Master of Science

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Liu, Cheng. "Advanced system design and signal processing techniques for converged high-speed optical and wireless applications." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/49058.

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The ever-increasing data traffic demand drives the evolution of telecommunication networks, including the last-mile access networks as well as the long-haul backbone networks. This Ph.D. dissertation focuses on system design and signal processing techniques for next-generation converged optical-wireless access systems and the high-speed long-haul coherent optical communication systems. The convergence of high-speed millimeter-wave wireless communications and high-capacity fiber-optic backhaul networks provides tremendous potential to meet the capacity requirements of future access networks. In this work, a cloud-radio-over-fiber access architecture is proposed. The proposed architecture enables a large-scale small-cell system to be deployed in a cost-effective, power-efficient, and flexible way. Based on the proposed architecture, a multi-service reconfigurable small-cell backhaul network is developed and demonstrated experimentally. Additionally, the combination of high-speed millimeter-wave radio and fiber-optic backhaul is investigated. Several novel methods that enable high-spectral-efficient vector signal transmission in millimeter-wave radio-over-fiber systems are proposed and demonstrated through both theoretical analysis and experimental verification. For long-haul core networks, ultra-high-speed optical communication systems which can support 1Terabit/s per channel transmission will soon be required to meet the increasing capacity demand in the core networks. Grouping a number of tightly spaced optical subcarriers to form a terabit superchannel has been considered as a promising solution to increases channel capacity while minimizing the need for high-level modulation formats and high baud rate. Conventionally, precise spectral control at transmitter side is required to avoid strong inter-channel interference (ICI) at tight channel spacing. In this work, a novel receiver-side approach based on “super receiver” architecture is proposed and demonstrated. By jointly detecting and demodulating multiple channels simultaneously, the penalties associated with the limitations of generating ideal spectra can be mitigated. Several joint DSP algorithms are developed for linear ICI cancellation and joint carrier-phase recovery. Performance analysis under different system configurations is conducted to demonstrate the feasibility and robustness of the proposed joint DSP algorithms, and improved system performance is observed with both experimental and simulation data.

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Vasseur, Jerome. "Multiwavelength laser sources for broadband optical access networks." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11462.

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The objective of the proposed research is to develop multiwavelength lasers as cost-efficient sources for broadband optical access networks. Todays telecommunications networks have widely adopted optical fiber as the backbone transmission medium. Optical fiber systems are promising candidates for the broadband access networks to offer high-speed and future-proof services. To harness the available bandwidth in fiber and to meet the ever-growing bandwidth demand, wavelength division multiplexing (WDM) techniques have been investigated. There have been intense research activities for the creation of new low-cost laser sources for such emerging applications. In this context, multiwavelength fiber ring lasers have been significantly investigated as they present many advantages, including simple structure, low-cost, and selectable multiwavelength operation. We propose a new laser system architecture that emits alternate multiwavelength picosecond pulses operating at room temperature. Optical signal generation is based on a single active component, an unbalanced Mach-Zehnder interferometer, inserted in an actively mode-locked erbium-doped fiber ring laser to provide both intensity modulation and wavelength-selective filtering. Time and frequency controls of the light emission are reached by inserting an additional modulator and a periodic filter in the cavity. This approach focuses on the application of multiwavelength lasers as sources for WDM passive optical networks.

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Cen, Min. "Study on Supervision of Wavelength Division Multiplexing Passive Optical Network systems." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-42362.

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The wavelength-division-multiplexed passive optical network (WDM-PON) offers many advantages such as large bandwidth per user, easy management, high network security and low insertion loss enabling long-reach and/or high split-ratio. However, with the rapid development and growing interest for deployment of WDM-PON, the PON systems are becoming increasingly vulnerable to various failures. Therefore, network supervision becomes extremely important to guarantee an appropriate level of network reliability performance. The aim of PON supervision is to provide automated test and diagnostic capability without compromising the available bandwidth for services. An essential function is to detect any kind of deterioration in the network that can cause suspended services and to remotely localize these faults in order to avoid the high cost arising from troubleshooting. In this thesis, we evaluate several existing WDM PON supervision methods, based on which two simple and cost-effective new solutions are proposed to localize fiber failures in WDM PON systems. In the first solution, a conventional optical time domain reflectometry (OTDR) and a switch unit are employed, while in the second method, a novel architecture based on N×N arrayed waveguide grating (AWG) is proposed. Both methods are able to localize failures in feeder fiber and drop fibers without e.g. using expensive tunable OTDRs. A patent has been filed based on the second solution. The first proposed method is validated by simulations using VPI Transmission Maker. According to the results, this supervision method is able to give accurate measurement of many different types of failures that may happen in a fiber link. Furthermore, VPI is examined in terms of its future applicability in modeling complete PON supervision methods based on OTDR.

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CALLIARI, FELIPE. "AUTOMATIC HIGH-DYNAMIC AND HIGH-RESOLUTION PHOTON COUNTING OTDR FOR OPTICAL FIBER NETWORK MONITORING." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2017. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=31668@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
Neste trabalho é apresentado o desenvolvimento de uma estrutura automatizada para o monitoramento de fibras ópticas. Esta estrura consite em dois tipos de reflectômetros ópticos por contagem de fótons no domínio do tempo e um filtro de tendências que é utilizado para detectar as falhas em uma fibra óptica de forma automatizada. O primeiro OTDR por contagem de fótons apresenta uma faixa dinâmica de 32 dB com resolução espacial de 6 m, já o segundo OTDR apresenta uma faixa dinâmica de 14 dB e uma resolução de 3 cm. Foi demonstrada a sua capacidade de detectar falhas automaticamente em um enlace óptica e de sintonização no monitoramento de redes passivas WDM.
In this work the development of an automated structure for the monitoring of optical fibers is presented. This structure consists of two types of Photon Counting Optical Time Domain Reflectometers and a trend filter that is used to detect fiber faults in an automated way. The first Photon Counting OTDR has a 32 dB dynamic range with spatial resolution of 6 m, while the second OTDR has a 14 dB dynamic range and a resolution of 3 cm. Its ability to automatically detect faults in an optical fiber link and tunability for monitoring of optical WDM networks has been demonstrated.

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Tsutsumi, Takuya. "Field Measurement and Analysis of Next-Generation Optical Access Network with Optical Amplifiers." Kyoto University, 2018. http://hdl.handle.net/2433/232417.

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Wang, Yunmiao. "A Quasi-distributed Sensing Network Based on Wavelength-Scanning Time-division Multiplexed Fiber Bragg Gratings." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/39324.

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Structural health monitoring (SHM) has become a strong national interest because of the need of reliable and accurate damage detection methods for aerospace, civil and mechanical engineering infrastructure. Health monitoring of these structures usually requires the sensors to have such features as large area coverage, maintenance free or minimum maintenance, ultra-low cost per measurement point, and capability of operation in harsh environments. Fiber Bragg grating (FBG) has attracted considerable interest for this application because of its compactness, electromagnetic immunity, and excellent multiplexing capability. Several FBG multiplexing techniques have been developed to increase the multiplexing number and further reduce the unit cost. To the authorâ s best knowledge, the current demonstrated maximum multiplexing number are 800 FBG sensors in a single array using optical frequency domain reflectometry (OFDR), whose maximum fiber span is limited by the coherence length of light source. In this work, we proposed and demonstrated a wavelength-scanning time-division multiplexing (WSTDM) of 1000 ultra-weak FBGs for distributed temperature sensing. In comparison with the OFDR method, the WSTDM method distinguishes the sensors by different time delays, and its maximum operation distance, which is limited by the transmission loss of the fiber, can be as high as tens of kilometers. The strong multiplexing capability and low crosstalk of the ultra-weak FBG sensors was investigated through both theoretical analysis and experiment. An automated FBG fabrication system was developed for fast FBG fabrication. With this WSTDM method, we multiplexed 1000 ultra-weak FBGs for distributed temperature sensing. Besides the demonstrated temperature measurement, the reported method can also be applied to measure other parameters, such as strain, pressure.
Ph. D.

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Rand-Nash, Thomas. "Characterizing capital and operational tradeoffs resulting from fiber-to-the-home optical network architecture choice." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/53222.

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Thesis (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2009.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 127-128).
This thesis explores the impact of relative lifecycle cost tradeoffs on technology strategy, and characterizes two factors driving these costs: population demographics, and uncertainty in component costs. The methodology developed consists of three novel components which address gaps in the current literature in the areas of large-scale network design, multi-attribute population characterization, and cost modeling. Three technologies representing near, mid, and long-term fiber-to-the-home gigabit passive optical network solutions, and seven implementation strategies are dimensioned for two significantly different population demographics, each representing large coverage regions containing millions of subscribers. The methodology is able to successfully characterize how relative network topologies changed as a function of population attributes, revealing complex cost tradeoffs between technology strategies.
by Thomas Rand-Nash.
S.M.

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24

Štěpán, Petr. "Trendy přístupových sítí." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220562.

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This work deals with the modern trends in FTTX, but mainly focuses on FTTH, who represents the connecting of fiber to the homes of the participants. Sum up the basic problems of communication on the optical fibre, followed by comparison with other types of access networks. Another part is the analysis of the problems of construction and a description of the optical network topologies and technologies used in FTTH. In following chapter are characterized active and passive elements forming AON and PON networks. Next part deals with the study of the most common services that can be on the optical access network to operate. They are mainly associated with the TriplePlay services. An integral part of the project is the study of management and supervision optical networks. In the main part is created real model situation where is the requirement for the creation of optical access networks with broadband of TriplePlay, followed by selection of appropriate options and detailed project with a selection of active and passive elements with economic balance.

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Huang, Zhengyu. "Novel Segment Deformable Mirror Based Adaptive Attenuator Used In Wavelength Division Multiplexed Optical Communications Network." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/34454.

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In wavelength division multiplexed (WDM) optical communication networks, signals are amplified periodically by optical amplifiers. Since the gain profiles of optical amplifiers are not flat, equalizers are usually used to maintain signal powers at different wavelengths in equal to avoid crosstalk and data loss. However, fixed attenuation can only compensate fixed input power and amplification. In active network, input power and amplifier gain change with time. Active level compensation at each wavelength is needed. An adaptive attenuator is a device with a chromatically variable transmissivity used to equalize channel powers in wavelength-division multiplexing (WDM) fiber-optic communication lines. In this thesis, a method of Fourier analysis of multi-beam interference is developed. It is shown that the total electric field and relative phase delay of each beam form a Fourier transform pair. Thus methods and properties of Fourier analysis are applicable in multi-beam interference analysis and design. Fourier transform based design is presented. Novel devices that apply such design principles are introduced. Principles and structures of novel adaptive attenuators based on various technologies such as segment deformable mirror, liquid crystal, phase modulation array are given. Simulation results for segment deformable mirror based adaptive attenuator are presented.
Master of Science

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26

Van, Loggerenberg Samuel Pieter. "Optimization of passive optical network planning for fiber-to-the-home applications / Samuel Pieter van Loggerenberg." Thesis, North-West University, 2013. http://hdl.handle.net/10394/9538.

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Passive optical networks (PONs) are point-to-multipoint networks where a single Central Office (CO) is connected to a number of downstream Optical Network Units (ONUs) via a single optical fiber by splitting the optical signal with passive splitters. Due to technology advances and increasing bandwidth requirements, these networks have moved to last mile deployment, also known as fiber-to-the-home (FTTH). The planning of these PONs are traditionally done by hand, but automated methods can be used to decrease deployment costs and planning time. Even though a number of methods have been proposed to address this problem through the solving of integer linear programming (ILP) models, they suffer from limited availability, inaccuracies and limited scalability due to the problem complexity. This dissertation focusses on improving the accuracy of these models as well as improving scalability to a point where large-scale problems can be solved feasibly. To address this, a basic model is implemented to capture the network structure and verified accordingly. Results show this model can be solved quickly, but has large discrepancies with real-world plans. Refinements in the form of fiber duct sharing, network constraints, multiple splitter types and economies of scale among others are then incorporated into a refined model and solved. Analysis of the experimental results indicates improved accuracy and lower deployment costs, at the expense of increasing computation effort considerably. Heuristic techniques are then examined to improve computational performance, including an elementary heuristic (ELEM), the Branch Contracting Algorithm (BCA) and problem decomposition. It is demonstrated that through the use of k-means clustering, the refined model can be solved in a fraction of the time while keeping deployment costs comparably low.
Thesis (MIng (Computer and Electronic Engineering))--North-West University, Potchefstroom Campus, 2013

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Doležal, Ondřej. "Experimentální práce s POF - polymerová optická vlákna." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2015. http://www.nusl.cz/ntk/nusl-220395.

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In this diploma thesis, the reader is familiarized with polymer optical fiber (POF). Firstly is mentioned theoretical background of optical fibers and optical transmission. The following are the basic properties and significant parameters of POF, a more detailed description of each type POF and their essential advantages and disadvantages in comparison with established optical fibers based on glass. The next chapter describes the area of practical issues: working with fibers and fiber installation, as well as the available connectors and methods of measurement of POF. Closely are analyzed knowledge of the practice, including the utilize in the aerospace and automotive industries, as well as in industrial networks, access data networks and local area networks. The practical part includes the measurement of basic transmission and mechanical parameters, including analysis of the results. The conclusion summarizes all the findings and results of this work, including possible future developments.

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Mahloo, Mozhgan. "Reliability versus Cost in Next Generation Optical Access Networks." Licentiate thesis, KTH, Optical Network Laboratory (ON Lab), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-122380.

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The ever increasing demands of Internet users caused by the introduction of new high bandwidth applications and online services as well as the growing number of users and devices connected to the Internet, bring many challenges for the operators, especially in the last mile section of the network. Next generation access architectures are expected to offer high sustainable bandwidth per user. They also need to support a much larger service areas to decrease number of current central offices and hence potentially save the network expenditures in the future. Obviously, it requires high capacity and low loss transmission and optical fiber technology is the only future proof candidates for broadband access. Although this technology has already been widely deployed in the core networks, it is hard to use the same expensive devices made for core segment to solve the last mile bottlenecks, due to the low number of users sharing the network resources (and deployment cost). Therefore, the next generation optical access (NGOA) networks need to be designed with consideration of cost efficiency in the first place. Network reliability is also turning to be an important aspect for the NGOA networks as a consequence of long reach, high client count and new services requiring uninterrupted access. Consequently, new architectures not only need to be cost efficient but also they should fulfill the increasing reliability requirements. Although several NGOA alternatives have been proposed in the literatures, there is not yet an agreement on a single architecture. As described earlier, network expenditure and reliability performance are the two main factors to be considered. Therefore, this thesis concentrates on finding a suitable alternative for future broadband access by evaluating the reliability performance and total cost of ownership for several NGOA candidates. In particular, in this thesis we analyze the tradeoff between the cost needed to deploy backup resources and the reliability performance improvement obtained by the provided survivability mechanism. First, we identified the suitable NGOA candidates by comparing two main groups of optical access networks, namely passive optical networks (PONs) and active optical networks (AONs), in terms of cost, reliability performance and power consumption. The initial results have shown that wavelength division multiplexing PON (WDM PON) is the most promising alternative for the NGOA networks because of its high potential capacity, low cost and power consumption. So we continued our studies by investigating two WDM-based PON architectures regarding their cost and reliability performance. The study has also included a proposed fiber layout compatible with these two candidates aiming to minimize the required investment needed to offer protection. Our primary results confirmed that hybrid PON (HPON) is the best alternative for the NGOA networks. Therefore we further analyzed this candidate considering several variants of HPON. The most important components and sections of the HPON, which need to be protected to decrease the impact of each failure in the network have been identified. Based on these outcomes, two resilience architectures protecting the shared part of the HPON were proposed and their reliability performance parameters as well as cost of protection were evaluated. According to the results, using our proposed protection schemes a considerable improvement in reliability performance of the HPON variants can be provided at minor extra investment. We also introduced a cost efficient HPON architecture with different levels of protection for users with various reliability requirements, i.e. the protection of shared parts of the access network for all the connected users and end-to-end resilience scheme for some selected ones (e.g., business users). To gain an overall view on the cost efficiency of the proposed architecture, we evaluated the investment required for deploying these schemes considering several network upgrading paths towards a protected network. Moreover, a sensitivity analysis investigating the influence of network deployments time and the density of the users with higher availability requirements was presented. In summary, we have shown that HPON is able to fulfill the main NGOA requirements such as high bandwidth per-user, large coverage and client count. The work carried out in the thesis has proved that HPON can also offer high reliability performance while keeping the network expenditures at an acceptable level. Moreover, low power consumption and high flexibility in resource allocation of this architecture, makes it a winning candidate for the NGOA networks. Therefore, HPON is a promising architecture to be deployed as NGOA network in the near future considering the fact that components are soon to be available in the market.

QC 20130530

FP7 EU project, Optical Access Seamless Evolution(OASE)

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Bobkovič, Peter. "Širokopásmová FTTx přípojka na architektuře WDM - PON." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2010. http://www.nusl.cz/ntk/nusl-218328.

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This masters thesis is focusing on the issue of passive optic access networks. It is dealing with the limiting factors for broadband connections, especially attenuation of fibre optics and dispersion. It is also dealing with most commonly used standards of passive optic networks. It clarifies the issue of wavelength-division multiplexing, its advantages and disadvantages, used standards, various types of components for the WDM-networks, their characteristics, application etc. In the practical part of the work you can find the measuring and diagnostics of the passive optic network EPON. It contains measuring by the direct method OLTS, measuring by the Pon Power Meter and optic reflectometer OTDR. At the end I am dealing with the measuring of splitter in the rate of 1:16.

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Kondicz, Dávid. "Optický přenos informací - bezpečnost přenosu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2015. http://www.nusl.cz/ntk/nusl-220547.

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The submitted work deals with issues of optical transmissions and its security. We will become familiar with a variety of transferability of information, based on which we can assess the advantages and disadvantages of each technology as compared to optical information transmission. Based on acquired information we will try to implement interception of optical communication of cable TV provider.

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31

SATO, Ken-ichi, Hiroshi HASEGAWA, Yoshiyuki YAMADA, and Fumisato NARUSE. "Virtual Fiber Networking and Impact of Optical Path Grooming on Creating Efficient Layer One Services." 電子情報通信学会, 2012. https://search.ieice.org/.

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Abbasi, Hoseini Afshin. "Experimental study of turbulent flow with dispersed rod-like particles through optical measurements." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-24956.

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The knowledge of the behavior of non-spherical particles suspended in turbulent flows covers a wide range of applications in engineering and science. Dispersed two-phase flows and turbulence are the most challenging subjects in engineering, and when combined it gives rise to more complexities as the result of the inherent stochastic nature of the turbulence of the carrier-phase together with the random distribution of the dispersed phase. Moreover, for anisotropic particles the coupling between the translation and rotation of particle increases the complication. Because of the practical importance of prolate particleladen turbulent flows, the plenty of numerical and experimental works have been conducted to study such suspensions. Numerical approaches have given valuable insight of turbulent suspension flows, although the computation has been only carried out at the macro scale and models, not including flow distortion around the particle, comprise the detail of the flow in the order of a particle size. In addition, the model of the forces imposed on the particle by the fluid and mass point treatment are strictly valid for infinitely small particle having size less than all scales of the fluid turbulence. Fully resolved solution at the scale of the dispersed phase in turbulent flows for high Reynolds number has been recently performed but is still a challenge. On the other hand, the presence of particle as the dispersed phase makes experimental measurements much more complicated than those with single phase as a result of particles interference. The area of considerable difficulty with this type of experiments is the measurement of the fluid-phase velocity remarkably close to the particle surface. Generally, experimental researches have been concentrated on measuring the mean velocity and Reynolds stresses of the carrier-phase, and the mean velocity, fluctuations, orientation and accumulation of the non-spherical particles. Higher-order quantities, including Lagrangian particle velocity correlations, the carrier-phase turbulence modulation, and two-particle and particlefluid velocity correlations are also of interest. It has been found that the rotational and translational movements of the fibershaped particle depend on the nature of carrier-phase field and fiber characteristics such as aspect ratio, fiber Stokes number, fiber Reynolds number, and the ratio of fiber to flow length scale. With the development of PIV (Particle Image Velocimetry) and PTV (Particle Tracking Velocimetry) techniques, it has been appeared that combined PIV/PTV will be the best available choice for the experimental study of dispersed two-phase flows. The purpose of combined PIV/PTV measurement of two-phase systems is simultaneous measurements of fluid and suspended objects, where the PIV measurement of the fluid phase are combined with PTV measurement of the dispersed phase. The objective of this doctoral thesis is to study the behavior of rod-like particles suspended in wall-bounded turbulent flow through simultaneous PIV/PTV measurements of the velocity of the flow field and particle motion. As a representative of rod-like particles, I have employed cellulose acetate fibers with the length to diameter ratio (aspect ratio) larger than one. Here, It has been considered only dilute suspensions with no flocculation; thus fiber-fiber interaction is negligible. The measurements have been conducted within the parallel planes (2D view) illuminated by laser in the streamwise direction in thin film suspension flowing on the water table setup at Linné FLOW Centre, KTH Mechanics Lab. It is shown that this setup is a well-behaved experimental model of half channel flows often used in Direct Numerical Simulation (DNS) investigations. Therefore, the experimental results are comparable to their DNS counterpart where it is convenient. A single camera PIV technique has been used to measure flowing suspension. Therefore, it has been needed to preprocess images using a spatial median filter to separate images of two phases, tracer particles as representative of fluid and fibers suspended. The well-known PIV processing algorithms have been applied to the phase of fluid. I have also introduced a novel algorithm to recognize and match fibers in consecutive images to track fibers and estimate their velocity. It is not feasible to study all relevant aspects of particle-laden turbulent flows in a single study. In this study, I present the statistics of the rotational and translational motion of fiber-like particles and the surrounding fluid velocity. To the author’s knowledge, remarkably little experimental work has been published to date on simultaneous measurement of fiber motion and turbulence field in a turbulent fiber suspension flow to reveal dynamics of fibers in this regime. Therefore, the results of this work will be profitable in better understanding of such multiphase flows. The statistical analysis of the translational motion of fibers shows that the size of fiber is a significant factor for the dynamical behavior of the fiber near the wall. It has been observed that, in the region near the wall, the probability of presence of the long fibers is high in both the high-speed and low-speed streaks of flow, and the mean velocity of fibers almost conforms to the mean velocity of flow; whereas the short fibers are mostly present in the low-speed areas, and the fiber mean velocity obey the dominant flow velocity in these areas. In the far-wall regions, the translation of fibers is practically unaffected by the aspect ratio, whereas it depends crucially on the wall-normal distance. Moreover, it was found that in the case of long fibers near the wall, the low speed fibers mostly are orientated in streamwise direction. On the other hand, there is no preferential orientation for fast long fibers. Although wall-normal velocities were not measured in this study, it is hypothesized that this behavior is a result of fibers being affected by the sweep and ejection events known to occur in wall-bounded turbulent flow. The fast fibers are in sweep environment and comes from the upper layer. The low speed fibers are into ejection areas in the vicinity of the wall, and the wall has a stabilizing effect on them. The short fibers are still oriented mostly in streamwise direction for a certain range of low velocity. Furthermore, since a considerable change of the fiber behavior is observed in a certain ratio of the fiber length to the fiber distance from the solid wall, it is supposed that this ratio is also a prominent parameter for the behavior of fiber near the wall. The results presented are in terms of viscous wall units wherever are denoted by superscript “+”.

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33

Gossage, Steven A. "Delivery of Very High Bandwidth with ATM Switches and SONET." International Foundation for Telemetering, 1993. http://hdl.handle.net/10150/608861.

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International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada
To deliver high bandwidth, a ubiquitous inter-/intra-building cable plant consisting of single mode and multimode fiber as well as twisted pair copper is required. The selection of the "glue" to transport and interconnect distributed LANs with central facility resources over a pervasive cable plant is the focus of this paper. A description of the traditional problems that must be overcome to provide very high bandwidth beyond the narrow confines of a computer center is given. The applicability of Asynchronous Transfer Mode (ATM) switching (interconnection) and Synchronous Optical NETwork (SONET) (transport) for high bandwidth delivery is described using the environment and requirements of Sandia National Laboratories. Other methods for distributing high data rates are compared and contrasted. Sandia is implementing a standards based foundation utilizing a pervasive single mode fiber cable plant, SONET transport, and ATM switching to meet the goals of gigabit networking.

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Angilella, Vincent. "Design optimal des réseaux Fiber To The Home." Thesis, Evry, Institut national des télécommunications, 2018. http://www.theses.fr/2018TELE0004/document.

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Pour les opérateurs, les réseaux FTTH représentent à la fois la solution de référence pour répondre à la demande croissante de trafic fixe, et un investissement considérable dû à leur mise en place. Le but de ces travaux est d'assurer le déploiement de réseaux de qualité à moindre coût. Nous commençons à présenter les différents aspects de la planification de ces réseaux qui en font un problème complexe. La littérature concernée est abordée afin d'exhiber les nouveaux défis que nous relevons. Puis nous élaborons des stratégies permettant de trouver la meilleure solution dans différents contextes. Plusieurs politiques de maintenance ou d'utilisation du génie civil sont ainsi explorées. Les problèmes rencontrés sont analysés à la lumière de divers outils d'optimisation (programmation entière, inégalités valides, programmation dynamique, approximations, complexités, inapproximabilité...) que nous utilisons et développons selon nos besoins. Les solutions proposées ont été testées et validées sur des instances réelles, et ont pour but d'être utilisées par Orange
For operators, FTTH networks are the most widespread solution to the increasing traffic demand. Their layout requires a huge investment. The aim of this work is to ensure a cost effective deployment of quality networks. We start by presenting aspects of this network design problem which make it a complex problem. The related literature is reviewed to highlight the novel issues that we solve. Then, we elaborate strategies to find the best solution in different contexts. Several policies regarding maintenance or civil engineering use will be investigated. The problems encountered are tackled using several combinatorial optimization tools (integer programming, valid inequalities, dynamic programming, approximations, complexity theory, inapproximability…) which will be developed according to our needs. The proposed solutions were tested and validated on real-life instances, and are meant to be implemented in a network planning tool from Orange

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Angilella, Vincent. "Design optimal des réseaux Fiber To The Home." Electronic Thesis or Diss., Evry, Institut national des télécommunications, 2018. http://www.theses.fr/2018TELE0004.

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Pour les opérateurs, les réseaux FTTH représentent à la fois la solution de référence pour répondre à la demande croissante de trafic fixe, et un investissement considérable dû à leur mise en place. Le but de ces travaux est d'assurer le déploiement de réseaux de qualité à moindre coût. Nous commençons à présenter les différents aspects de la planification de ces réseaux qui en font un problème complexe. La littérature concernée est abordée afin d'exhiber les nouveaux défis que nous relevons. Puis nous élaborons des stratégies permettant de trouver la meilleure solution dans différents contextes. Plusieurs politiques de maintenance ou d'utilisation du génie civil sont ainsi explorées. Les problèmes rencontrés sont analysés à la lumière de divers outils d'optimisation (programmation entière, inégalités valides, programmation dynamique, approximations, complexités, inapproximabilité...) que nous utilisons et développons selon nos besoins. Les solutions proposées ont été testées et validées sur des instances réelles, et ont pour but d'être utilisées par Orange
For operators, FTTH networks are the most widespread solution to the increasing traffic demand. Their layout requires a huge investment. The aim of this work is to ensure a cost effective deployment of quality networks. We start by presenting aspects of this network design problem which make it a complex problem. The related literature is reviewed to highlight the novel issues that we solve. Then, we elaborate strategies to find the best solution in different contexts. Several policies regarding maintenance or civil engineering use will be investigated. The problems encountered are tackled using several combinatorial optimization tools (integer programming, valid inequalities, dynamic programming, approximations, complexity theory, inapproximability…) which will be developed according to our needs. The proposed solutions were tested and validated on real-life instances, and are meant to be implemented in a network planning tool from Orange

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Winkler, Aleš. "Parametry sítí FTTx - kvalita služeb." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219697.

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The main subject of this diploma thesis is to make a proposal to improve the optical access network for the transmission of Triple play services. I would here to the reader clarify method of proposal of optical network. There are described the kinds of optical access networks with parameters, for which we must look by their construction. There are described the modern methods of construction optical network too. In the theoretical part are discussed used architecture of networks too. I met here known standards, which I compared for big importance by their choice. A reason of construction of optical network are services known like Triple play. These services together with their problems and parameters are here discussed too. At the end of theoretical part I listed here measuring method for getting negative attribute distorting the led signal. In practical part the locality witch use the optical signal as the source of information is ordered. These network use unfit connections and has less possibilities than usual and this is the reason, why is the network not able to supply Triple play in requested quality. At first the analysis of ordered network was needed. Situation was complicated by the fact, that it has been prohibited entrance to me. The structure of network and network parts was known and documented by me. I made the proposals to improve this network in practical part. By the first proposal remained original kind of access network FTTB, but used new parts with higher performance. By the second proposal I made the network FTTH, by which it was possible to use the last haul optical cables with treatment and using new elements. It was needed to create solution by flat units. The resulting proposals are here evaluated, compared and cost evaluated. For rejection of access to optical network I did not make measuring, so I made simulation for variant FTTH for getting some parameters negative acting transmission.

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Gajdoš, Jaroslav. "Metodika měření optických sítí FTTH." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218131.

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The main topic of this master thesis is a FTTH measurement methodology of optical networks and its specific features 9 compared with other measurement methodologies. Also, the use of the FTTH measurement methodology: an example of measurements of a passive network with splitter 1:8 and analysis of the results of these experimental measurements. The first part of the thesis concerns itself with the description of optical networks and characteristics and features of the FTTH networks. A detailed description of the passive optical networks is provided: e.g. the optical network unit ONU, the optical line termination OLT, and, most importantly, the passive optical splitter. The wavelength division multiplex 9 WDM 9 which is used in passive optical networks is also described in detail. The chapter on measurement methodologies focuses in detail and provides many examples of currently used measurement methodologies of these networks. The best results are currently achieved with the OTDR methodology. The second part of the thesis concentrates on the description of the measurement of a passive optical network with splitter 1:8 using the methods described in previous chapters. As conclusion, a detailed analysis, assessment of the results and their usefulness when put into practice is provided.

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Chen, Jiajia. "Design, analysis and simultion for optical access and wide-area networks." Doctoral thesis, KTH, Mikroelektronik och tillämpad fysik, MAP, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10348.

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Due to the tremendous growth of traffic volume caused by both exponential increase of number of Internet users and continual emergence of new bandwidth demanding applications, high capacity networks are required in order to satisfactorily handle the extremely large amount of traffic. Hence, optical fiber communication is the key technology for the network infrastructure. This thesis addresses design, analysis and simulation of access and core networks targeting important research problems, which need to be tackled for the effective realization of next generation optical networks. Among different fiber access architectures, passive optical network (PON) is considered as the most promising alternative for the last mile connection due to its relatively low cost and resource efficiency. The inherent bursty nature of the user generated traffic results in dynamically changing bandwidth demand on per subscriber basis. In addition, access networks are required to support differentiated quality of service and accommodate multiple service providers. To address these problems we proposed three novel scheduling algorithms to efficiently realize dynamic bandwidth allocation in PON, along with guaranteeing both the priority and fairness of the differentiated services among multiple users and/or service providers. Meanwhile, because of the increasing significance of reliable access to network services, an efficient fault management mechanism needs to be provided in PON. In addition, access networks are very cost sensitive and the cost of protection should be kept as low as possible. Therefore, we proposed three novel cost-effective protection architectures keeping in mind that reliability requirement in access networks should be satisfied at the minimal cost. Regarding the optical core networks, replacing electronic routers with all-optical switching nodes can offer significant advantages in realizing high capacity networks. Because of the technological limitations for realizing all-optical nodes, the focus is put on the ingenious architecture design. Therefore, we contributed on novel switching node architectures for optical circuit and packet switching networks. Furthermore, we addressed different aspects of routing and wavelength assignment (RWA) problem, which is an important and hard task to be solved in wavelength routed networks. First, we proposed an approach based on the information summary protocol to reduce the large amount of control overhead needed for dissemination of the link state information in the case of adaptive routing. In addition, transparency in optical networks may cause vulnerability to physical layer attacks. To target this critical security related issue, we proposed an RWA solution to minimize the possible reachability of a jamming attack. Finally, in order to evaluate our ideas we developed two tailor-made simulators based on discrete event driven system for the detailed studies of PON and switched optical networks. Moreover, the proposed tabu search heuristic for our RWA solution was implemented in C++.
QC 20100707

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Guillory, Joffray, and Joffray Guillory. "Radio over Fiber (RoF) for the future home area networks." Phd thesis, Université Paris-Est, 2012. http://tel.archives-ouvertes.fr/tel-00786479.

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The evolution of the Home Area Network (HAN) is lead by the proliferation of connected devices inside the home and the deployment of high broadband access network which now allows the delivery of services that can exceed 1Gbit/s. To ensure efficient in-house exchanges, the HAN has to move rapidly toward multi-Gigabit/s connections, in particular the wireless connectivity generally preferred by the customers. Current wireless systems have limited capacities, but new radio standards delivering data-rates up to 7Gbit/s are emerging. Nevertheless, as they address the unlicensed millimeter-wave band, from 57 to 66 GHz, their radio coverage is limited to a single room. Indeed, at such frequencies, the free-space losses are high and the waves do not cross the walls. This thesis proposes to solve this problem by means of the Radio over Fiber (RoF) technology. This consists in capturing the 60GHz radio signals emitted in one room, converting them into optical signals for transmission through optical fibers, and reemitting them in another room. Thus, several RoF transducers will be installed in the home and interconnected by a suitable optical infrastructure to create systems acting at the same time as repeaters and as distribution systems. From the viewpoint of the HAN market, such systems will be competitive only if they are low cost. As a consequence, this work focuses on direct modulation with direct detection (IM-DD) at Intermediate Frequency (IF). In other words, the 60GHz signal is down-converted at a lower frequency around 5GHz before the laser modulation and up-converted to 60GHz after the photodetection. Concerning the optical fiber, silica multimode fiber (MMF) is privileged as it allows the use of low cost and largely available optoelectronic devices working at 850nm.The thesis proposes different RoF architectures, from point-to-point interconnecting two rooms to multipoint-to-multipoint acting as logical buses. After an analog characterization of the optoelectronic components, the RoF link and the domestic cable, these architectures are designed, built and characterized step by step using OFDM modulation according to existing wireless 60GHz standards. Real-time transmissions between commercial devices have also been performed to validate these architectures. Moreover, advanced RoF infrastructures are proposed. First, the RoF systems can be easily improved if the access to their optical media is managed by the radio MAC layer. This approach is therefore studied showing its feasibility. Secondly, an optical system, seen by users as a premium product, has to support the legacy home services commonly used as well as the new ones that could emerge in the future. Thus, innovative multiservice and multiformat infrastructures conveying on a unique optical cable wired IP data, broadcast terrestrial or satellite television, the 60GHz wireless connectivity, and specific formats as HDMI signals are proposed and tested

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Frank, Florian. "Hybrid analogue & digital access network architectures for the mobile/fixe infrastructure convergence." Phd thesis, Université Paris-Est, 2011. http://tel.archives-ouvertes.fr/tel-00665650.

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In order to realize the convergence of the optical infrastructure of fixed and mobile access networks, the objective of this thesis is to study the solutions for distributing native radio carriers through typical optical access networks.The first Part describes the contexts and the main physical properties of the optical and radio access networks: from nowadays deployed Fiber To The Home (FTTH) systems, and their expected evolutions, to the current radio system Universal Mobile Telecommunications System (UMTS) towards the expected requirements of modern mobile radio systems. This allows to settle the optical environment in which the Radio over Fiber(RoF)-functionalities will have to be integrated, and to know on which radio systems'figures of merits to focus on when implementing it. The second Part shows the benefit and possibilities of re-using the optical infrastructure of the fixed access networks for distributed radio systems. Then a review of the analog and digital RoF techniques is proposed, and their feasibility of integration into legacy FTTH systems is discussed. The third part deals with the computing and simulations of an analog RoF-system where the optical link is either passive or optically pre-amplified, and even boosted. The goal is to provide numerical results to the practical lab. results of the second half of the fourth part where the Signal to Noise Ratio (SNR) matters. Therefore successively formal expressions, numerical results for simple 2-tone signals and more realistic UMTS signals are considered. The fourth and last part deals with the obtained practical results. These can be split into two main categories : Error Vector Magnitude (EVM)-oriented results where an Avalanche Photo-Detector (APD) is used for legacy and extended-reach PON architectures using a direction shared Semiconductor Optical Amplifier (SOA) ; and an Adjacent/Alternate Channel power Leakage Ratio (ACLR)-driven part where the focus is seton a very critical figure of merit of radio systems, especially in the downlink. The latter part turned out to be mandatory and prevailing over the initially considered EVM concerns. Hence several RoF architectures, compatible with PONs, are introduced in order to overcome the non-linearities undergone by the RoF-signals, induced by the chromatic dispersion of the PON's fiber and the laser chirp, and degrading the ACLR performances

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Mustafa, Haithem A. "Opto-VLSI-based adaptive optical power splitter/combiner for next generation dynamic optical telecommunication networks." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2013. https://ro.ecu.edu.au/theses/923.

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The demand for optical power splitters is growing globally, due to the rapid deployment of fibre-to-the-premises, optical metropolitan area network (MAN), and active optical cables for TV/Video signal transport. Optical splitters play an important role in passive optical network (PON) technology by enabling several hundred users to share one optical line terminal. However, current PONs, which use fixed optical power splitters, have limited reconfigurability particularly in adding/dropping users to/from an optical network unit. An adaptive optical power splitter (OPS) can dynamically reallocate the opticalpower in the entire network according to the real-time distribution of users and services, thus providing numerous advantages such as improve an optical network efficiency, scalability, and reliability. An adaptive OPS is also important for realizing self-healing ring-to-ring optical MAN, thus offering automatic communication recovery when line break occurs. In addition, future optical line protection systems will require adaptive optical splitters to switch optical signals from faulty lines to active power lines, avoid the use of optical attenuators and/or amplifiers, and achieve real time line monitoring. An adaptive OPS can also be incorporated in tunable optical dispersion compensators, optical attenuator and optical gain equalizer, and reconfigurable optical switches. This thesis proposes and demonstrates the principle of a novel Opto-VLSI-based adaptive optical splitter/combiner for next generation dynamic optical telecommunication networks. The proposed splitter structure enables an input optical power to be split adaptively into a larger number of output fibre ports, through optimized phase holograms driving the Opto-VLSI processor. The new adaptive optical splitter has additional advantages including lossless operation, adequate inter-port crosstalk, compressed hardware and simple user interface. This thesis demonstrates, in particular, the concept of an adaptive optical power splitter employing an Opto-VLSI processor and a 4-f imaging system experimentally in three stages as follow: (i) a 1×2 adaptive optical power splitter based on an Opto-VLSI processor, a fibre collimator array and 4-f imaging systems (single lens), (ii) a 1×4 adaptive optical power splitter based on an Opto-VLSI processor, a fibre array and 4-f imaging systems (single lens), and (iii) a 1×N lossless adaptive optical power splitter structure integrating an Opto-VLSI processor, optical amplifiers, a fibre array, and an array of 4-f imaging systems (lens array). The thesis also demonstrates the concept of an adaptive optical signal combiner which enables multiple signals to be combined with user-defined weight profiles into a single fibre port. Experimental results demonstrate that an input optical signal can arbitrarily be split into N signals and coupled into optical fibre ports by uploading optimized multicasting phase holograms onto the Opto-VLSI processor. They also demonstrate that N input optical signals can be dynamically combined with arbitrary weights into a single optical fibre port. Excellent agreement between theoretical and experimental results is demonstrated. The total insertion loss of the optical power splitter is only 5 dB. Results also show that the optical amplifiers can compensate for the insertion and splitting losses, thus enabling lossless splitter operation. A crosstalk level around -25 dB and a wavelength spectral range exceeding 40 nm is experimentally realized. In addition, a novel broadband adaptive RF power splitter/combiner based on Opto-VLSI processor is proposed and experimentally demonstrated. By uploading optimized multicasting phase holograms onto the software-driven Opto-VLSI processor, the input RF signal is dynamically split and directed to different output ports, with userdefined splitting ratios. Also, multiple input RF signals can be dynamically combined with arbitrary user-defined weights. As a proof-of-concept demonstration, two input RF signals are dynamically combined with different user-defined weight profiles. We also propose and demonstrate a photonic microwave filter based on the use of an Opto-VLSI-based adaptive optical combiner. The experimental results demonstrate that the developed Opto-VLSI-based adaptive optical combiner can dynamically route multiple input optical signals to a single output, with user-defined weight profiles, thus realising a tunable microwave filter. Overall this Opto-VLSI-based adaptive optical power splitter should allow as many as 32 output ports to be supported while achieving high splitting resolution and dynamic range. This will greatly enhance the efficiency of optical communication networks.

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Kužela, Jan. "Návrh, realizace a měření pasivní optické sítě." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-317033.

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The aim of this thesis is to formulate the design of optical access network in designated area. The design is focused on the physical network layer and it covers optical fibers, cable protectors and links, optical hubs, racks and active components. The thesis also docu- ments network architecture, the configuration of active components and provides results from monitoring of selected network segments. The thesis consists of the theoretical part and practical part. In the theoretical part, there is an introduction to optical networks, their configurations (FTTH, FTTB, FTTC, FTTN), relevant networking standards and technologies. The practical part of the thesis covers design proposal of a network located in Slavičín. The design reuses infrastructure and technologies of existing network. The proposed design follows FTTH architecture which has benefits of low maintenance cost and it also fulfills GPON standard.

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Girard-Jollet, Joana. "Subsea optical links characterization assisted by machine learning." Electronic Thesis or Diss., Institut polytechnique de Paris, 2024. http://www.theses.fr/2024IPPAT048.

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Face à la demande croissante en bande passante Internet, disposer de systèmes de communication optique robustes est plus crucial que jamais.Au-delà des avancées dans les technologies et composants individuels, la performance du système de communication dépend également de la façon dont ces composants sont utilisés et combinés pour que la configuration globale soit optimisée. Souvent, la performance du réseau est limitée par les prédictions qu’on peut en faire avant que le réseau soit déployé.Cela rend la précision de notre prédiction de performance essentielle pour l’optimisation du réseau. L’objectif de cette thèse est de caractériser et de contrôler les principales sources de distorsion du signal optique dans les liaisons sous-marines, principalement pour prédire la performance future du réseau avec des marges minimales. Nous avons concentré notre étude sur deux distorsions physiques : les effets non linéaires de Kerr et les pertes dépendantes de la polarisation. Cette thèse aborde les défis liés a l’estimation de la performance et au contrôle du réseau afin de proposer de nouveaux outils de surveillance et des lignes directrices pour optimiser les systèmes de transmission
With the growing demand for internet bandwidth, having robust optical communication systems is more crucial than ever. Beyond the advances in individual technologies and components, the performance of the communication system also depends on how intelligently these components are used and combined so that the overall configuration is optimized. Often, network performance is limited by predeployment predictions, making accurate estimation essential for optimization. The objective of this thesis is to characterize and monitor key sources of distortion in subsea links, primarily to predict the network’s future performance with minimal margins. We focused on two physical impairments: nonlinear Kerr effects and polarizationdependent loss. The thesis addresses the challenges of performance estimation and network monitoring to introduce novel monitoring tools and provide guidelines for optimizing transmission systems

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Chang, Ching-Hung. "Dynamic bandwidth allocation MAC protocols for gigabit-capable passive optical networks." Thesis, University of Hertfordshire, 2008. http://hdl.handle.net/2299/2452.

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The research initiatives addressed in this thesis are geared towards improving the performance of passive optical networks (PONs) through the development of advanced dynamic bandwidth allocation (DBA) protocols. In particular, the aim of the research undertaken is to enhance the quality of service (QoS) offered by standard PONs by means of providing subscribers with service level agreement (SLA) to fulfil applications and associated bandwidth requirements on demand. To accomplish the research objectives, a novel service and bandwidth focused DBA protocol is developed for standard time division multiplexing (TDM), gigabit-capable PONs (GPONs) by flexibly assigning a guaranteed minimum bandwidth to each optical network unit (ONU),terminated at subscribers premises. Modelling and simulation of the developed algorithms have displayed a tenfold enhancement in network performance, showing a superior performance to other published DBA protocols, in terms of mean packet delay. To accomplish protocol optimisation, the ONU upstream transmission properties of TDM-PONs have been further analysed and subsequently the ONU data transfer order in each communication cycle has been dynamically configured to increase the network upstream throughput by overlapping the upstream transmission period with parts of the bandwidth request-allocation process between OLT and ONUs. In addition, with the objective of extending the application of the developed protocol to long-reach PONs by means of reducing the augmented propagation delays due to the network’s extensive reach, the concept of virtual communication cycles has been incorporated into the optimised DBA algorithm. This approach demonstrates comparable transmission efficiency in the context of subscriber throughput and packet delay as in a standard PON but at much longer distances from the network exchange. To overcome the inevitably limited communication capacity of single wavelength TDM protocols and with the transportation of the ever increasing, time-sensitive, multi-media services in mind, a novel multi-wavelength DBA protocol is then developed to be applied to a wavelength division multiplexing–PON. With this protocol, both the downstream and upstream network capacity is dynamically adjusted according to subscribers’ service level and bandwidth demand in each polling cycle as opposed to a fixed upstream network capacity in TDM-PONs. It therefore also demonstrates improved upstream transmission efficiency.

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Hsueh, Yu-Ting. "Frontiers of optical networking technologies: millimeter-wave radio-over-fiber and 100g transport system for next-generation high-data-rate applications." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43681.

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The enabling technologies and the issues of next-generation millimeter-wave wireless access network and 100G long-haul optical transport network were developed and identified. To develop a simple and cost-effective millimeter-wave optical-wireless system, all-round research on the technical challenges of optical millimeter-wave generation, transmission impairments compensation, and simple base station design were discussed. Several radio-over-fiber systems were designed to simultaneously deliver multi-band wireless services on a single optical infrastructure, enabling converged system control and quality maintenance in central office. For the 100G optical transport network, the issues related to successful implementations of transmitter, fiber link, and receiver of a 112-Gb/s polarization-division multiplexing-quadrature phase shift keying (PDM-QPSK) system were comprehensively explored. The experimental results based on the constructed 112-Gb/s testbed indicated that careful dispersion management can effectively increase nonlinearity tolerance. Furthermore, the special emphasis on the two impairments of the 100G network with reconfigurable optical add-drop multiplexers: passband narrowing and in-band crosstalk, was studied. The results demonstrated that these impairments can be readily predicted with proper experimental and simulation efforts.

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Kalfas, Georgios. "Medium-transparent MAC protocols for converged optical wireless networks." Doctoral thesis, Universitat Politècnica de Catalunya, 2017. http://hdl.handle.net/10803/406358.

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In order to address the explosive demand for high-capacity and omnipresent wireless access, modern cell-based wireless networks are slowly adopting two major solution roadmaps. The first is the employment of small-cell formations in order to increase the overall spectral efficiency, whereas the second is the employment of higher frequency bands, such as the mm-wave 60GHz band, that offers vast amounts of bandwidth. Depending on the specific application, the above solutions inevitably require the installation and operational management of large amounts of Base Stations (BSs) or Access Points (APs), which ultimately diminishes the overall cost-effectiveness of the architecture. In order to reduce the system cost, Radio over Fiber (RoF) technology has been put forward as an ideal candidate solution, due to the fact that it provides functionally simple antenna units, often termed as Remote Antenna Units (RAUs) that are interconnected to a central managing entity, termed as the Central Office (CO), via an optical fiber. Although extensive research efforts have been dedicated to the development of the physical layer aspects regarding RoF technologies, such as CO/RAU physical layer design and radio signal transport techniques over fiber, very limited efforts have con-centrated on upper layer and resource management issues. In this dissertation, we are concerned with access control and resource management of RoF-based mm-wave network architectures targeting the exploitation of the dual medium and its centralized control properties in order to perform optimal optical/wireless/time resource allocation. In this dissertation, we propose a Medium-Transparent MAC (MT-MAC) protocol that concurrently administers the optical and wireless resources of a 60GHz RoF based network, seamlessly connecting the CO to the wireless terminals through minimal RAU intervention. In this way, the MT-MAC protocol forms extended reach 60GHz WLAN networks offering connectivity amongst wireless devices that are attached to the same or different RAUs under both Line of Sight (LOS) and non LOS conditions. The notion of medium-transparency relies on two parallel contention periods, the first in the optical domain and the second in the wireless frequency and time domains, with nested dataframe structures. The MT-MAC operation is based on a proposed RAU design that allows for wavelength selectivity functions, thus being compatible with completely passive optical distribution network implementations that are predominately used by telecom operators today. Two variants of the MT-MAC protocol are considered. The first offers dynamic wavelength allocation with fixed time windows, whereas the second targets fairness-sensitive applications by offering dynamic wavelength allocation with dynamic transmission opportunity window sizes, based on the number of active clients connected at each RAU. Both variants of the protocol are evaluated by both simulation and analytical means. For the latter part, this thesis introduces two analytical models for calculating saturation throughput and non-saturation packet delay for the converged MT-MAC protocol. Finally, this thesis presents an extensive study regarding the network planning and formation of 60GHz Gigabit WLAN networks when the latter are deployed over existing Passive Optical Network (PON) infrastructures. Three possible architectures where studied: i) the RoF approach, ii) the Radio & Fiber approach and iii) the hybrid RoF-plus-R&F approach that combines the properties of both the aforementioned architectures. During the elaboration of this thesis, one major key conclusion has been extracted. The work proposed in this thesis considers that there is a fundamental requirement for implementing new converged optical/wireless MAC protocols, that have the complete overview of both available resources in order to effectively administer the hybrid Radio-over-Fiber networks.
A fin de atender la demanda explosiva de alta capacidad y acceso inalámbrico omnipresente, las redes inalámbricas basadas en celdas están poco a poco adoptando dos principales guías de solución. La primera es el empleo de formaciones de celdas pequeñas con el fin de aumentar la eficiencia espectral global, mientras que la segunda es el empleo de bandas de frecuencia superior, como la banda de 60GHz, la cual ofrece una gran cantidad de ancho de banda. Dependiendo de la aplicación en específico, las soluciones anteriores inevitable-mente requieren de una instalación y una gestión operativa de grandes cantidades de Estaciones Base o Puntos de Acceso, que en última instancia disminuye la rentabilidad de la arquitectura. Para reducir el coste, la tecnología radioeléctrica por fibra (RoF) se presenta como una solución ideal debido al hecho de que proporciona unidades de antenas de sim-ple funcionamiento, a menudo denominadas Unidades de Antenas Remotas (RAUs), las cuales están interconectadas a una entidad central de gestión, denominada Oficina Central (CO), a través de la fibra óptica. A pesar de que se han dedicado muchos esfuerzos de investigación al desarrollo de varios aspectos de las capas física con respecto a las tecnologías RoF, muy pocos esfuerzos se han concentrado en la capa superior y cuestiones de gestión de recursos. En esta tesis, nos enfocando en el control de acceso y gestión de recursos de arquitecturas RoF y comunicaciones milimétricas, con el fin de aprovechar y explotar el medio dual y las propiedades para realizar una óptima asignación de los recursos ópticos, inalámbricos y temporales. Nosotros proponemos un protocolo Transparente al Medio MAC (MT-MAC) que simultáneamente administre los recursos ópticos e inalámbricos de una red RoF a 60GHz, conectando a la perfección el CO a los terminales inalámbricos a través de una mínima intervención RAU. El protocolo MT-MAC forma unas redes WLAN 60GHz de alcance extendido, ofreciendo así conectividad entre los dispositivos inalámbricos que están conectados al mismo o diferentes RAUs bajo con o sin Línea de Vista (condiciones LOS o NLOS) respectivamente. La noción de transparencia al medio se basa en dos períodos de contención para-lelos, el primero en el dominio óptico y el segundo en la frecuencia inalámbrica y dominio del tiempo, con estructuras de datos anidados. La operación MT-MAC se basa en proponer un diseño RAU que permita la selectividad de funciones de longitud de onda. Dos variantes del protocolo MT- MAC son considerados; el primer ofrece asignación de longitud de onda dinámica con ventanas de tiempo fijo, mientras que la segunda tiene como objetivo entornos de aplicaciones sensibles ofreciendo asignación de longitud de onda con tamaño de ventana de oportunidad de transmisión dinámico, basado en el número de clientes conectados en cada RAU. Ambas variantes del protocolo están evaluadas tanto por medios analíticos como de simulación. En la segunda parte, esta tesis introduce dos modelos analíticos para calcular el rendimiento de saturación y no saturación del retardo de paquetes para el protocolo MT-MAC convergente. Finalmente, esta tesis presenta un extenso estudio de la planificación de red y la formación de redes 60GHz Gigabit WLAN cuando esta se encuentra desplegada sobre las ya existente infraestructuras de Redes Ópticas Pasivas (PONs). Tres posibles arquitecturas han sido estudiadas: i) el enfoque RoF, ii) el enfoque Radio y Fibra , y iii) el enfoque híbrido, RoF más R&F el cual combina las propiedades de ambas arquitecturas anteriormente mencionadas. Durante la elaboración de esta tesis, se ha extraído una importante conclusión: hay un requerimiento fundamental para implementar nuevos protocolos ópticos/inalámbricos convergentes, que tengan una completa visión de ambos recursos disponibles para poder administrar efectivamente las redes de tecnología RoF.

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Guillory, Joffray. "Radio over Fiber (RoF) for the future home area networks." Thesis, Paris Est, 2012. http://www.theses.fr/2012PEST1083/document.

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L'évolution des Réseaux Locaux Domestiques (RLD) est influencée par l'augmentation irréfrénée du nombre de terminaux connectés dans nos domiciles et par le déploiement de réseaux d'accès optiques haut débit qui délivrent désormais des services dépassant le Gigabit/s. Pour continuer à échanger efficacement les données, les RLD doivent évoluer vers le multi-Gigabit/s, et plus particulièrement la très appréciée connectivité sans fil. Les systèmes radio actuels ont des capacités limitées, néanmoins de nouveaux standards dont le débit excède 7Gbit/s voient le jour. Mais comme ces derniers exploitent la bande millimétrique, entre 57 et 66 GHz, leur couverture radio est limitée à la taille d'une pièce. En effet, à de telles fréquences, les pertes en espace libre sont très élevées et les ondes ne traversent pas les murs. Cette thèse propose de résoudre cette limitation au moyen de solutions Radio sur Fibre (RoF pour Radio over Fiber). Cette technique consiste à capturer les signaux radio émis dans une première pièce, puis à les convertir en signaux optiques pour les transmettre par fibre optique jusqu'à une seconde pièce où ils seront réémis. Plusieurs transducteurs RoF seront donc installés dans le domicile et interconnectés entre eux au moyen d'une infrastructure optique adaptée, créant ainsi des systèmes se comportant à la fois comme répéteurs and comme système de distribution. Pour le marché du RLD, de telles solutions sont compétitives que si elles sont bas coût. Par conséquent, ce travail se focalise sur la modulation directe avec détection directe (IM-DD) en Fréquence Intermédiaire (FI). En d'autres termes, le signal radio à 60GHz est translaté à une plus faible fréquence, autour de 5GHz, pour moduler directement un laser, puis il est restitué à 60GHz après la détection directe. Concernant la fibre optique, la multimode silice (MMF) est privilégiée puisqu'elle permet l'utilisation de composants optoélectroniques bas coût et largement disponible. Cette thèse propose différentes architectures RoF, de la point-à-point reliant deux pièces à la multipoint-à-multipoint agissant comme un bus logique. Après une caractérisation analogique des composants optoélectroniques, du lien RoF et du câble domestique, ces architectures sont construites et caractérisées étape par étape sur la base d'une modulation OFDM conforme aux standards radio 60GHz. Des transmissions temps réel entre terminaux commerciaux sont également réalisées afin de valider ces architectures. Pour finir, des infrastructures RoF avancées sont proposées. Premièrement, les systèmes RoF peuvent être améliorés si l'accès à leur couche optique est contrôlé par la couche MAC radio. Cette approche est donc étudiée, démontrant ainsi sa faisabilité. Deuxièmement, les systèmes optiques, perçus par les utilisateurs comme des produits premium, doivent supporter aussi bien les services de base du RLD que ceux qui vont émerger dans les années à venir. Ainsi, des infrastructures multiservice and multiformat innovantes transportant sur un unique câble optique des données IP, la télévision hertzienne et satellite, les signaux radio 60GHz et d'autres formats spécifiques tels que l'HDMI sont proposées puis testées
The evolution of the Home Area Network (HAN) is lead by the proliferation of connected devices inside the home and the deployment of high broadband access network which now allows the delivery of services that can exceed 1Gbit/s. To ensure efficient in-house exchanges, the HAN has to move rapidly toward multi-Gigabit/s connections, in particular the wireless connectivity generally preferred by the customers. Current wireless systems have limited capacities, but new radio standards delivering data-rates up to 7Gbit/s are emerging. Nevertheless, as they address the unlicensed millimeter-wave band, from 57 to 66 GHz, their radio coverage is limited to a single room. Indeed, at such frequencies, the free-space losses are high and the waves do not cross the walls. This thesis proposes to solve this problem by means of the Radio over Fiber (RoF) technology. This consists in capturing the 60GHz radio signals emitted in one room, converting them into optical signals for transmission through optical fibers, and reemitting them in another room. Thus, several RoF transducers will be installed in the home and interconnected by a suitable optical infrastructure to create systems acting at the same time as repeaters and as distribution systems. From the viewpoint of the HAN market, such systems will be competitive only if they are low cost. As a consequence, this work focuses on direct modulation with direct detection (IM-DD) at Intermediate Frequency (IF). In other words, the 60GHz signal is down-converted at a lower frequency around 5GHz before the laser modulation and up-converted to 60GHz after the photodetection. Concerning the optical fiber, silica multimode fiber (MMF) is privileged as it allows the use of low cost and largely available optoelectronic devices working at 850nm.The thesis proposes different RoF architectures, from point-to-point interconnecting two rooms to multipoint-to-multipoint acting as logical buses. After an analog characterization of the optoelectronic components, the RoF link and the domestic cable, these architectures are designed, built and characterized step by step using OFDM modulation according to existing wireless 60GHz standards. Real-time transmissions between commercial devices have also been performed to validate these architectures. Moreover, advanced RoF infrastructures are proposed. First, the RoF systems can be easily improved if the access to their optical media is managed by the radio MAC layer. This approach is therefore studied showing its feasibility. Secondly, an optical system, seen by users as a premium product, has to support the legacy home services commonly used as well as the new ones that could emerge in the future. Thus, innovative multiservice and multiformat infrastructures conveying on a unique optical cable wired IP data, broadcast terrestrial or satellite television, the 60GHz wireless connectivity, and specific formats as HDMI signals are proposed and tested

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48

Schwartz, Marlène. "Conception d'un réseau local à intégration de services : modélisation et évaluation de performances." Paris 6, 1986. http://www.theses.fr/1986PA066142.

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Le travail présenté à deux objectifs: - l'un est de mettre en évidence les problèmes auxquels se heurtent les concepteurs de réseaux locaux à intégration de services, et de tenter d'identifier les paramètres à prendre en compte lors de la conception d'un réseau local; - l'autre concerne plus particulièrement la recherche de modèles simples dans le but d'évaluer les performances d'une certaine catégorie de protocoles d'accès. On propose en effet un modèle simple permettant d'analyser les performances d'un réseau en anneau utilisant une méthode d'accès de type jeton. Dans la terminologie des files d'attente ce type de système se traduit par un ensemble de files servies cycliquement par un unique serveur.

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Boiyo, Duncan Kiboi, and Romeo Gamatham. "Optimization of flexible spectrum in optical transport networks." Thesis, Nelson Mandela Metropolitan University, 2017. http://hdl.handle.net/10948/14609.

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The ever-increasing demand for broadband services by end-user devices utilising 3G/4G/LTE and the projected 5G in the last mile will require sustaining broadband supply from fibre-linked terminals. The eventual outcome of the high demand for broadband is strained optical and electronic devices. The backbone optical fibre transport systems and techniques such as dense wavelength division multiplexing (DWDM), higher modulation formats, coherent detection and signal amplification have increased both fibre capacity and spectrum efficiency. A major challenge to fibre capacity and spectrum efficiency is fibre-faults and optical impairments, network management, routing and wavelength assignment (RWA). In this study, DWDM and flexible spectrum techniques such as wavelength assignment and adjustment, wavelength conversion and switching, optical add and drop multiplexing (OADM) and bitrate variable transmission have been experimentally optimized in a laboratory testbed for short- and long-haul optical fibre networks. This work starts by experimentally optimising different transmitters, fibre-types and receivers suitable for implementing cost effective and energy efficient flexible spectrum networks. Vertical cavity surface-emitting lasers (VCSELs) and distributed feedback (DFB) lasers have been studied to provide up to 10 Gb/s per channel in 1310 nm and 1550 nm transmission windows. VCSELs provide wavelength assignment and adjustment. This work utilises the non-return-to-zero (NRZ) on-off keying (OOK) modulation technique and direct detection due to their cost and simplicity. By using positive intrinsic negative (PIN) photo-receivers with error-free BER sensitivity of -18±1 dBm at the acceptable 10-9-bit error rate (BER) threshold level, unamplified transmission distances between 6 km and 76 km have been demonstrated using G.652 and G.655 single mode fibres (SMFs). For the first time, an all optical VCSEL to VCSEL wavelength conversion, switching, transmission at the 1550 nm window and BER evaluation of a NRZ data signal is experimentally demonstrated. With VCSEL wavelength conversion and switching, wavelength adjustments to a spectrum width of 4.8 nm (600 GHz) can be achieved to provide alternative routes to signals when fibre-cuts and wavelength collision occurs therefore enhancing signal continuity. This work also demonstrates a technique of removing and adding a wavelength in a bundle of DWDM and flexible channels using an OADM. This has been implemented using a VCSEL and a fibre Bragg grating (FBG) providing a wavelength isolation ratio of 31.4 dB and ~0.3 𝑑𝐵 add/drop penalty of 8.5 Gb/s signal. As a result, an OADM improves spectrum efficiency by offering wavelength re-use. Optical impairments such as crosstalk, chromatic dispersion (CD) and effects of polarization mode dispersion (PMD) have been experimentally investigated and mitigated. This work showed that crosstalk penalty increased with fibre-length, bitrate, interfering signal power and reduced channel spacing and as a result, a crosstalk-penalty trade-off is required. Effects of CD on a transmitted 10 Gb/s signal were also investigated and its mitigation techniques used to increase the fibre-reach. This work uses the negative dispersion fibres to mitigate the accumulated dispersion over the distance of transmission. A 5 dB sensitivity improvement is reported for an unamplified 76 km using DFB transmitters and combination of NZDSF true-wave reduced slope (TW-RS) and submarine reduced slope (TW-SRS) with + and – dispersion coefficients respectively. We have also demonstrated up to 52 km 10 Gb/s per channel VCSEL-based transmission and reduced net dispersion. Experimental demonstration of forward Raman amplification has achieved a 4.7 dB on-off gain distributed over a 4.8 nm spectral width and a 1.7 dB improvement of receiver sensitivity in Raman-aided 10 Gb/s per wavelength VCSEL transmission. Finally, 4.25-10 Gb/s PON-based point to point (P2P) and point to multipoint (P2MP) broadcast transmission have been experimentally demonstrated. A 10 Gb/s with a 1:8 passive splitter incurred a 3.7 dB penalty for a 24.7 km fibre-link. In summary, this work has demonstrated cost effective and energy efficient potential flexible spectrum techniques for high speed signal transmission. With the optimized network parameters, flexible spectrum is therefore relevant in short-reach, metro-access and long-haul applications for national broadband networks and the Square Kilometre Array (SKA) fibre-based signal and data transmission.

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Haris, Muhammad. "Advanced modulation formats for high-bit-rate optical networks." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24811.

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Thesis (Ph.D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008.
Committee Chair: Chang, Gee-Kung; Committee Co-Chair: Yu, Jianjun; Committee Member: Altunbasak, Yucel; Committee Member: Ji, Chunayi; Committee Member: Ralph, Stephen; Committee Member: Xu, Jun.

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Dissertations / Theses on the topic 'Optical fiber network'

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