Tesi sul tema "Optical fibered networks"
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1
May, Alix. "Novel receiver-based techniques for the monitoring of physical parameters in optical fiber networks". Electronic Thesis or Diss., Institut polytechnique de Paris, 2023. http://www.theses.fr/2023IPPAT013.
Abstract (sommario):
Dans les réseaux à fibre optique, le monitoring massif a suscité un intérêt important pour leur permettre d'être plus autonomes et élastiques. Au fil des années, diverses techniques de monitoring basées sur le traitement numérique du signal côté récepteur ont été proposées. Ces techniques sont particulièrement intéressantes car elles ne nécessitent pas de matériel supplémentaire et sont moins coûteuses. Dans ma thèse, je me suis concentrée sur les techniques de monitoring de la puissance longitudinale d'un lien optique, basées sur l'analyse des effets de propagation non linéaires. Dans un premier temps, j'ai proposé d'utiliser une technique existante pour estimer la valeur d'une perte de puissance dans une liaison optique point à point et je l'ai validée expérimentalement. Ensuite, j'ai généralisé la méthode d'estimation des pertes de puissance et l'ai appliquée à un réseau maillé. L'utilisation de différents trajets lumineux sur ce réseau m'a permis de montrer une augmentation de la précision de l'estimation des valeurs de perte. Afin d'élargir les possibilités de mise en œuvre de cette méthode, j'ai étudié ensuite expérimentalement l'application de la technique d'estimation du profil de puissance sur une longue liaison optique pour valider son utilisation pour les systèmes sous-marins. Enfin, je propose d'utiliser cette technique pour surveiller un autre type de pertes de puissance, la perte dépendante de la polarisation (PDL). La PDL est présente dans les composants optiques tels que les commutateurs et les amplificateurs. Habituellement, seul le montant cumulé est surveillé. J'ai proposé d'utiliser une méthode similaire à celle des pertes de puissance, permettant de localiser un élément PDL variable et d'estimer sa variation. Ce dernier travail nous permet de nous rapprocher du type d'événement, ce qui est important pour prendre des solutions intelligentes et efficacesIn optical fibered networks, massive monitoring generated significant interest to allow them to be more autonomous and elastic. Over the years, various monitoring techniques based on the digital signal processing at the receiver side have been proposed. Those techniques are particularly interesting since they do not require additional hardware and are less costly. In my PhD, I focused on techniques to monitor the longitudinal power of an optical link, based on the analysis of non-linear propagation effects. First, I proposed to use an existing technique to estimate the value of a power loss in a point-to-point optical link and validated it experimentally. Then, I generalized the power losses estimation method and applied it to a meshed network. Using various lightpaths on this network allowed me to show experimentally an increase of the accuracy of the estimation of loss values. To broaden the possibilities of implementation of this method, I then investigate experimentally the application of the power profile estimation technique on a long optical link to validate its use for submarine systems. Finally, I propose to use this technique to monitor another type of power losses, polarization-dependent loss (PDL). PDL is present in optical components such as switches and amplifiers. Usually, only the accumulated amount is monitored. I proposed to use a similar method as with the power losses, allowing the location of a varying PDL element and the estimation of its variation. This latest work allows us to get closer to the type of event, which is important to take smart and effective solutions
2
Boiyo, Duncan Kiboi, e Romeo Gamatham. "Optimization of flexible spectrum in optical transport networks". Thesis, Nelson Mandela Metropolitan University, 2017. http://hdl.handle.net/10948/14609.
Abstract (sommario):
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.
3
Bignell, Allan M. "Photonic bus and photonic mesh networks : design techniques in extremely high speed networks /". *McMaster only, 1997.
4
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.
Abstract (sommario):
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.
5
Tariq, Sana. "Inside all-optical networks /". Online version of thesis, 2009. http://hdl.handle.net/1850/10960.
6
Dods, Sarah D. "Homodyne crosstalk in wavelength-division multiplexed ring and cus networks /". Connect to thesis, 2000. http://eprints.unimelb.edu.au/archive/00000597.
7
Zhang, Jian-Guo, e Zheng Li. "FIBER-OPTIC NETWORKS FOR TELEMETRY APPLICATIONS". International Foundation for Telemetering, 1992. http://hdl.handle.net/10150/608907.
Abstract (sommario):
International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, CaliforniaIn this paper, we investigate high-capacity fiber-optic networks for real-time telemetry applications. The network topologies and related network components are analyzed for telemetry fiber-optic Local Area Network (LAN) and Metropolitan Area Network (MAN) as well as MAN internetworking with LANs. Two types of multiplexing techniques, namely, Wavelength Division Multiplexing and Time Division Multiplexing, are proposed to support real-time high-capacity telemetry applications, and the perspective of such networks is also considered. Finally, the optical modulation technique and the choice of optical devices are discussed, which are based on improving the reliability of fiber-optic LANs and MANs.
8
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.
Abstract (sommario):
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.
9
Mysore, Sudhesh M. "Advances in optical power budgets and bandwidth capacity of broadband networks /". free to MU campus, to others for purchase, 1999. http://wwwlib.umi.com/cr/mo/fullcit?p9953885.
10
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/.
11
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.
Abstract (sommario):
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.
12
West, Lamar. "Analysis and simulation of reverse path laser clipping in subcarrier multiplexed hybrid fiber coax networks". Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/13301.
13
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.
Abstract (sommario):
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.
14
Kelly, Anthony Edward. "Optimisation of semiconductor optical amplifiers for optical networks". Thesis, University of Strathclyde, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366966.
15
Gamatham, Romeo Reginald Gunther. "Nonlinear effects with a focus on cross phase modulation and its impact on wavelength division multiplexing optical fibre networks". Thesis, Nelson Mandela Metropolitan University, 2013. http://hdl.handle.net/10948/6302.
Abstract (sommario):
The demand for faster data transmission is ever increasing. Wavelength division multiplexing (WDM) presents as a viable solution to increase the data transmission rate significantly. WDM systems are based on the ability to transmit multiple wavelengths simultaneously down the fibre. Unlike time division multiplexing (TDM) systems, WDM systems do not increase the data transfer by increasing the transmission rate of a single channel. In WDM systems the data rate per channel remains the same, only multiple channels carry data across the link. Dense wavelength division multiplexing (DWDM) promises even more wavelengths packed together in the same fibre. This multiplication of channels increases the bandwidth capacity rapidly. Networks are looking into making use of technology that will ensure no electronic signal regeneration at any point within the DWDM network. Examples are; reconfigurable optical add/drop multiplexers (ROADM) and optical cross connect (OXC) units. These components essentially enable network operators to split, combine and multiplex optical signals carried by optical fibre. WDM allows network operators to increase the capacity of existing networks without expensive re-cabling. This provides networks with the flexibility to be upgraded to larger bandwidths and for reconfiguration of network services. Further, WDM technology opens up an opportunity of marketing flexibility to network operators, where operators not only have the option to rent out cables and fibres but wavelengths as well. Cross phase modulation (XPM) poses a problem to WDM networks. The refractive index experienced by a neighbouring optical signal, not only depends on the signal’s intensity but on the intensity of the co-propagating signal as well. This effect leads to a phase change and is known as XPM. This work investigates the characteristics of XPM. It is shown that, in a two channel WDM network, a probe signal’s SOP can be steered by controlling a high intensity pump signal’s SOP. This effect could be applied to make a wavelength converter. Experimental results show that the degree of polarization (DOP) of a probe signal degrades according to a mathematical model found in literature. The pump and probe signals are shown to experience maximum interaction, for orthogonal probe-pump SOP vector orientations. This may be problematic to polarization mode dispersion compensators. Additionally, experimental results point out that the SOP of a probe signal is much more active in the presence of a high intensity pump, as compared to the single signal transmission scenario.
16
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.
Abstract (sommario):
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.
17
Xiao, Chunpeng. "Advanced link and transport control protocols for broadband optical access networks". Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-11082006-183908/.
Abstract (sommario):
Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2007.Chang, Gee-Kung, Committee Chair ; Zhou, G.Tong, Committee Member ; Copeland, John, Committee Member ; Riley, George, Committee Member ; Ingram, Mary Ann, Committee Member ; Ammar, Mostafa, Committee Member.
18
Smith, Craig Scott. "Implementing pipelined circuit switching on the PICA aligned offset cube topology". Thesis, Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/13362.
19
Liu, Feng. "Symmetrically multi-connected optical fiber wide area networks". Thesis, University of Ottawa (Canada), 1994. http://hdl.handle.net/10393/6704.
Abstract (sommario):
Self-routing all-optical WAN design is becoming more and more important in broadband communications. However, little has been done in this field. In this thesis, we propose a Multi-Dual Ring Connected Shuffle Network and a Multi-Shuffle Connected Shuffle Network for a WAN environment. The performance of the proposed architectures is studied under a uniform traffic pattern analytically and numerical results are provided. The Multi-Dual Ring Connected Shuffle Connected Networks are studied under the nonuniform traffic patterns with an analytical method 'extreme value analysis' and a simulation method 'random load generation'. All of the studies are done with respect to the Perfect Shuffle Networks. The proposed architectures outperform the conventional Perfect Shuffle Network proposed in the literature.
20
Ferreira, João Carlos de Melo. "Fiber amplifiers in transparent and dynamic optical networks". Doctoral thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/14090.
Abstract (sommario):
Doutoramento em Engenharia EletrotécnicaIn this thesis a study of optical fiber amplifiers in the context of transparent and dynamic optical networks is performed. We propose and validate a simplified model to estimate the gain profile and amplified spontaneous emission (ASE) noise of broadband counterpumped Raman fiber amplifiers (RFAs). The proposed model requires very low computational resources and it is suitable to be used in network planning tools. Based on the proposed model, we also present an algorithm to design flat gain counter-pumped RFAs for the extended C-band with low computational requirements. We experimentally verify that the pump-reflecting RFA presents a higher transient response due to channels add/drop, when compared to the conventional counter-pumped RFA. This makes this amplifier configuration unsuitable for transparent and dynamic optical networks. To mitigate the transient response due to channel add/drop, a pumpcontrolled gain-locked system based on the monitorization of the reflected pump power is proposed and validated numerically and experimentally. Following this approach, an efficient low-cost RFA suitable for dynamic optical networks is proposed. The dependence of the dynamical response of erbium-doped fiber amplifiers (EDFAs) on the pump wavelength, pump power, and temperature due to spectral hole burning (SHB) and site dependent pumping (SDP) is experimentally investigated. A dependence of the dynamic response on the pump wavelength, for amplifiers pumped around 1480 nm, is shown. In order to explain this dependence, the impact of SDP on the performance of EDFAs pumped at wavelengths around 1480 nm is investigated, both experimentally and numerically. As a result, an improved model incorporating the SDP effect for twolevel EDFAs is derived and experimentally validated.
Nesta tese é feito um estudo sobre amplificadores de fibra ótica no contexto de redes óticas transparentes e dinâmicas. Propomos e validamos um modelo simplificado para estimar o perfil do ganho e do ruído de emissão espontânea amplificada (ASE), para amplificadores de Raman (RFAs) contra propagantes. O modelo proposto requer baixos recursos computacionais e é adequado para ser usado em ferramentas de planeamento da rede. Com base no modelo proposto, apresentamos também um algoritmo com requisitos computacionais baixos para desenhar RFAs contra propagantes com ganho constante para a banda C estendida. Verificamos experimentalmente que um RFA contra propagante com reflexo da potência da bomba devido à adição/remoção de canais apresenta uma resposta transiente mais elevada, quando comparado com um RFA contra propagante convencional. Isto torna esta configuração inadequada para redes óticas transparentes e dinâmicas. Para mitigar a resposta transitória devido à adição/remoção de canais, um sistema de controlo do ganho baseado na monitorização da potência da bomba refletida é proposto e validado numérica e experimentalmente. Seguindo esta abordagem, um RFA contra propagante eficiente e de baixo custo adequado para redes óticas dinâmicas é proposto. A dependência da resposta dinâmica dos amplificadores de fibra dopada com érbio (EDFAs) em função do comprimento de onda da bomba, da potência da bomba e da temperatura devido ao spectral hole burning (SHB) e site dependent pumping (SDP) é investigada experimentalmente. Nos resultados obtidos é mostrada a dependência da resposta dinâmica em função do comprimento de onda da bomba, para amplificadores bombeados em torno de 1480 nm. Para explicar esta dependência, o impacto do SDP no desempenho de EDFAs bombeados em comprimentos de onda em torno de 1480 nm é investigado, tanto experimental como numericamente. Como resultado, um modelo mais completo, incorporando o efeito SDP para EDFAs de dois níveis é derivado e validado experimentalmente.
21
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.
Abstract (sommario):
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.
22
Gest, Johann. "Discrete fiber Raman amplifiers for agile all-photonic networks". Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103199.
Abstract (sommario):
This thesis is dedicated to the study of gain transients of discrete fiber Raman amplifiers and to the all-optical gain-clamping technique which is used to mitigate those transients.First, we study the standing-wave and the traveling-wave gain-clamping techniques when applied to a single discrete fiber Raman amplifier in the context of WDM channel add and drop. We take into account the operational regime of the amplifier and the location of the surviving channel in the amplification band. We demonstrate that the gain-clamped amplifier has to be operated in a regime below the critical regime to ensure that gain-clamping will be in effect. The efficiency of gain-clamping also depends on the feedback level of the lasing signal and on the implementation.
Next, we investigate the dynamic behaviour of a single discrete fiber Raman amplifier fed by multi-channel packet traffic. Our study shows that the efficiency of the gain-clamping technique to reduce the gain transients is dependent upon the operational regime of the amplifier and the packet duration. However, we also demonstrate that gain-clamping is not required to control the gain transients as the gain variations of the unclamped amplifier are small enough to be neglected.
We then theoretically analyse the dynamic response of cascades of discrete fiber Raman amplifiers subject to WDM channel add and drop. We consider cascades of mixed unclamped and gain-clamped amplifiers, varying the number and the position of the gain-clamped amplifiers in the cascade and taking into account the location of the surviving channel and the operational regime of the amplifiers. Our results show that the location of the gain-clamped amplifiers in a mixed cascade affects the transient characteristics and that it is possible to control the transients within tolerable limits.
Finally, we investigate the gain transients that occur in hybrid amplifiers in the presence of channel add and drop. We demonstrate that the gain-clamping technique can be used to mitigate the gain transients in hybrid amplifiers and that the surviving channel location does not influence the transient characteristics, contrary to the case of single and cascaded fiber Raman amplifiers.
23
Kalogerakis, Georgios. "Fiber optical parametric amplifiers and wavelength converters for next-generation optical networks /". May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
24
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.
Abstract (sommario):
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.
25
Maamoun, Khaled M. "Deploying Monitoring Trails for Fault Localization in All-optical Networks and Radio-over-Fiber Passive Optical Networks". Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23195.
Abstract (sommario):
Fault localization is the process of realizing the true source of a failure from a set of collected failure notifications. Isolating failure recovery within the network optical domain is necessary to resolve alarm storm problems. The introduction of the monitoring trail (m-trail) has been proven to deliver better performance by employing monitoring resources in a form of optical trails - a monitoring framework that generalizes all the previously reported counterparts. In this dissertation, the m-trail design is explored and a focus is given to the analysis on using m-trails with established lightpaths to achieve fault localization. This process saves network resources by reducing the number of the m-trails required for fault localization and therefore the number of wavelengths used in the network. A novel approach based on Geographic Midpoint Technique, an adapted version of the Chinese Postman’s Problem (CPP) solution and an adapted version of the Traveling Salesman’s Problem (TSP) solution algorithms is introduced. The desirable features of network architectures and the enabling of innovative technologies for delivering future millimeter-waveband (mm-WB) Radio-over-Fiber (RoF) systems for wireless services integrated in a Dense Wavelength Division Multiplexing (DWDM) is proposed in this dissertation. For the conceptual illustration, a DWDM RoF system with channel spacing of 12.5 GHz is considered. The mm-WB Radio Frequency (RF) signal is obtained at each Optical Network Unit (ONU) by simultaneously using optical heterodyning photo detection between two optical carriers. The generated RF modulated signal has a frequency of 12.5 GHz. This RoF system is easy, cost-effective, resistant to laser phase noise and also reduces maintenance needs, in principle. A revision of related RoF network proposals and experiments is also included. A number of models for Passive Optical Networks (PON)/ RoF-PON that combine both innovative and existing ideas along with a number of solutions for m-trail design problem of these models are proposed. The comparison between these models uses the expected survivability function which proved that these models are liable to be implemented in the new and existing PON/ RoF-PON systems. This dissertation is followed by recommendation of possible directions for future research in this area.
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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.
Abstract (sommario):
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.
27
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.
28
Ito, Christopher Joshua Shiro. "All-optical 3R regeneration for agile all-photonic networks". Thesis, Kingston, Ont. : [s.n.], 2007. http://hdl.handle.net/1974/508.
29
Vilar, Mateo Ruth. "Optical performance monitoring in optical packet-switched networks". Doctoral thesis, Universitat Politècnica de València, 2010. http://hdl.handle.net/10251/8926.
Abstract (sommario):
Para poder satisfacer la demanda de mayores anchos de banda y los requisitos de los nuevos servicios, se espera que se produzca una evolución de las redes ópticas hacia arquitecturas reconfigurables dinámicamente. Esta evolución subraya la importancia de ofrecer soluciones en la que la escalabilidad y la flexibilidad sean las principales directrices. De acuerdo a estas características, las redes ópticas de conmutación de paquetes (OPS) proporcionan altas capacidades de transmisión, eficiencia en ancho de banda y excelente flexibilidad, además de permitir el procesado de los paquetes directamente en la capa óptica. En este escenario, la solución all-optical label switching (AOLS) resuelve el cuello de botella impuesto por los nodos que realizan el procesado en el dominio eléctrico. A pesar de los progresos en el campo del networking óptico, las redes totalmente ópticas todavía se consideran una solución lejana . Por tanto, es importante desarrollar un escenario de migración factible y gradual desde las actuales redes ópticas basadas en la conmutación de circuitos (OCS). Uno de los objetivos de esta tesis se centra en la propuesta de escenarios de migración basados en redes híbridas que combinan diferentes tecnologías de conmutación. Además, se analiza la arquitectura de una red OPS compuesta de nodos que incorporan nuevas funcionalidades relacionadas con labores de monitorización y esquemas de recuperación.
Las redes ópticas permiten mejorar la transparencia de la red, pero a costa de aumentar la complejidad de las tareas de gesión. En este escenario, la monitorización óptica de prestaciones (OPM) surge como una tecnología capaz de facilitar la administración de las redes OPS, en las que cada paquete sigue su propia ruta en la red y sufre un diferente nivel de degradación al llegar a su destino. Aquí reside la importancia de OPM para garantizar los requisitos de calidad de cada paquete.Vilar Mateo, R. (2010). Optical performance monitoring in optical packet-switched networks [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/8926
Palancia
30
Stark, Andrew Joseph. "16QAM for next-generation optical transport networks". Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47732.
Abstract (sommario):
Fiber-optic networks are continually evolving to accommodate ever-increasing data transport rates demanded by modern applications, devices, and services. Network operators are now beginning to deploy systems with 100 Gb/s per-wavelength data rates while maintaining the 50 GHz dense wavelength division multiplexing grid that is (generally) standard for 10 Gb/s systems. Advanced modulation formats incorporating both amplitude- and phase-based data symbols are necessary to meet the spectral efficiency requirements of fiber-optic data transport. These modulation formats require coherent detection, enabling future networks to take advantage of advances in silicon CMOS via digital signal processing algorithms and techniques.
The primary challenge for future networks is the fiber nonlinear response; changes in the intensity of the propagating optical signal induce changes in the optical fiber refractive index. Limiting the allowed propagation intensity will reduce these nonlinear effects and correspondingly limit the total available signal-to-noise ratio (SNR) within the channel. Predicting the nonlinear SNR limits of fiber-optic transport for data rates 100 Gb/s and beyond is a primary purpose of this research.
This dissertation expressly matches several novel expressions for nonlinear interference accumulation to experimental data and demonstrates robust theoretical prediction of nonlinear transmission penalties. The experiments were performed to isolate the transmission performance of the fiber medium in the highly dispersive regime -- no dispersion compensation or Raman amplification was employed and all other hardware was kept static. These results are the first experimental validation of the nonlinear interference expressions on a fiber-type basis.
Second, this dissertation moves to data transport beyond per-wavelength rates of 100 Gb/s by employing 16QAM at baud rates as high as 32 GHz. It examines signal processing strategies for 16QAM transport and extends the nonlinear interference prediction techniques to 16QAM. The results reveal that the SNR requirements of 16QAM as limited by nonlinear interference will likely limit deployments to high-density regional and metro networks.
31
Hausien, H. H. "Pulse position modulation for optical fiber local area networks". Thesis, University of Bath, 1991. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292804.
32
Chen, David Yong. "The effects of noise in CATV distribution networks with star couplers and fiber amplifiers". Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-11102009-020312/.
33
Balon, Jiří. "Měřící metody klíčových parametrů v optických sítích". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2010. http://www.nusl.cz/ntk/nusl-218247.
Abstract (sommario):
The main goal of the master’s thesis was to familiarize with optical networks dilemma and its measuring during fabrication. The whole thesis is divided into several parts where the first part deals with optic fiber dilemma. It describes its kinds, properties and also suggests a basic principle of optic signal dispersion using these fibers. It describes also optical network FTTx architecture (Fiber To The x). The second part of the thesis focuses on methods of measuring key parameters of optical networks. Is brings out the methods of measuring optical loss and dispersive influences. The last and final part in focused on creating a methodical manual for measuring these networks during its fabrication and verifying measuring methods stated in the theoretical part inside a real network. Measuring was implemented on an optical network of Masaryk University in Brno.
34
Vasseur, Jerome. "Multiwavelength laser sources for broadband optical access networks". Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11462.
Abstract (sommario):
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.
35
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.
Abstract (sommario):
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.
36
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.
Abstract (sommario):
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.
37
Abu-Romoh, Mohanad. "Equalization in Optical Fiber Communication Using Model-based Neural Networks". Electronic Thesis or Diss., Institut polytechnique de Paris, 2023. http://www.theses.fr/2023IPPAT037.
Abstract (sommario):
Répondre à la demande croissante de transmission de données à haute vitesse nécessite des solutions efficaces pour atténuer la non linéarité dans les systèmes de communication optique.Les méthodes traditionnelles telles que la rétropropagation numérique (DBP) sont confrontées à d’importants défis computationnels, les rendant impraticables pour les systèmes du monde réel.Les modèles de réseaux neuronaux ont émergé comme une approche prometteuse pour résoudre ce problème. Deux approches principales existent pour la conception de réseaux neuronaux : les méthodes agnostiques au modèle et les méthodes basées sur le modèle. Les techniques agnostiques au modèle offrent de la flexibilité en termes de taille et d’hyper paramètres et peuvent être placées à différentes positions dans la chaîne de traitement du signal numérique (DSP) du récepteur. Cependant, elles exigent une taille substantielle et des données d’entraînement ´étendues pour fonctionner efficacement. En revanche, les approches basées sur le modèle emploient des réseaux neuronaux guidés par le modèle physique de la propagation du signal. Ces approches ont tendance à être plus compactes mais nécessitent une initialisation soigneuse pour une généralisation correcte. Une technique basée sur le modèle de premier plan est la rétropropagation numérique apprise (LDBP), qui optimise les paramètres DBP à l’aide de réseaux neuronaux.LDBP promet des performances améliorées ou une complexité réduite par rapport à DBP. Cette étude se concentre principalement sur LDBP, introduisant des simplifications par le biais du ”partage de paramètres” pour réduire les paramètres entraînables.De plus, nous proposons de réaffecter les systèmes hérités à gestion de la dispersion (DM) en incorporant des formats de modulation d’ordre supérieur tels que 16-QAM et 64-QAM pour améliorer les débits de données au sein de ces systèmes. Une analyse approfondie des performances et de la complexité démontre que les algorithmes proposés surpassent l’égalisation linéaire et DBP dans divers systèmes de transmissionMeeting the increasing demand for highspeed data transmission requires effective solutions for mitigating nonlinearity in optical communication systems. Traditional methods like Digital Backpropagation (DBP) face significant computational challenges,rendering them impractical for real-world systems. Neural network models have emerged as a promising approach to address this issue. Two primary approaches exist for designing neural networks: model-agnostic and model-based methods. Modelagnostictechniques offer flexibility in terms of size and hyperparameters and can be placed at various positions in the receiver’s Digital Signal Processing (DSP) chain. However, they demand substantial size and extensive training data in order to operate effectively.In contrast, model-based approaches employ neuralnetworks guided by the physical model of signal propagation. These approaches tend to be more compactbut require careful initialization for proper generalization. One prominent model-based technique isLearned Digital Backpropagation (LDBP), which optimizes DBP parameters using neural networks. LDBPoffers the promise of improved performance or reduced complexity compared to DBP. This study primarilyfocuses on LDBP, introducing simplifications through ”parameter sharing” to reduce trainable parameters.Additionally, we propose repurposing the legacy Dispersion-Managed (DM) systems, by incorporatinghigher-order modulation formats such as 16- QAM and 64-QAM, to enhance data rates within these systems. A comprehensive analysis of the performance and complexity demonstrates that the proposed algorithms outperform linear equalization andDBP in various transmission systems
38
Čičmanský, Tomáš. "Možnosti zvýšení propustnosti optovláknové průmyslové sítě". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2015. http://www.nusl.cz/ntk/nusl-220387.
Abstract (sommario):
Diploma thesis deals with problems of industrial networks using optical fiber as the main transmission lines. The task of the diploma work is to study and summarize the issues of industrial networks as well as the ways to increase their transmission capacity. In telecommunications and computer networks are generally used multiplexes, thanks to which we are able to achieve the desired transmission capacity. Consequently, the following work deals with the selection of the adequate solutions using described multiplexes as well as other transmission methods. The aim of the diploma work is to compare various renovation techniques of an old industrial network. Using this network as an example the work should demonstrate the individual problems and their solutions while considering different types of methods used. Based on the price, the performance and the difficulty to install other devices and transmission media we are able to select the appropriate solution for optical link.
39
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.
Abstract (sommario):
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.
40
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.
41
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.
Abstract (sommario):
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.
42
Savage, Shelby Jay 1978. "All-optical interferometric switches for data regeneration in fiber optic networks". Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40509.
Abstract (sommario):
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.Includes bibliographical references.
In the thirty years since the installation of the first fiber optic data link, data rates in installed fiber links have risen from a few Mb/s to tens of Gb/s. In the laboratory, data rates in a single optical fiber have already reached tens of Tb/s. These data rates greatly exceed electronic processing rates, so researchers have turned to all-optical signal processing to achieve many basic network tasks, like wavelength conversion, packet switching, and data regeneration. As data rates increase, the impairments caused by propagation through the glass of optical fiber become worse. Chromatic dispersion causes the temporal broadening of optical bits during propagation, leading to interference between neighboring bits. Nonlinear effects, like the nonlinear index of refraction and four-wave mixing, can cause interference between neighboring wavelength channels. The interaction of dispersion and nonlinearities can lead to variations in the timing of bits and the appearance of optical energy where there had been none. All these effects make 1-bits and 0-bits difficult to distinguish. Today, these distortions are overcome by electronic regenerators. Optical data streams are converted to electrical signals, processed electronically, converted back to an optical signal, and returned to the optical network. In this way, regenerators prevent the accumulation of noise and prevent noise from contributing to the production of more noise. The electronic solution is costly because of the extra hardware required for optical to electrical to optical conversions and performs poorly because of the losses incurred by those conversions. In this thesis, we investigate two regenerators that restore the data quality of ON/OFF keyed data without a conversion of the data to the electrical domain.
(cont..) Both regenerators are based on all-optical switches that take two inputs: the data pulses from the network, and a locally generated clock-pulse train. The all-optical switches then modulate the data pattern onto the clock-pulse train, which becomes the new data stream. The first switch we consider, the WMFUNI, uses the nonlinear properties of fiber to produce the switching action. Using the WMFUNI regenerator, we demonstrate the propagation of 10 Gb/s data over 20,000 km of commercial optical fiber. We also demonstrate the WMFUNI's ability to operate on 40-Gb/s data. Unfortunately, fiber has only a weak nonlinearity, so the WMFUNI is large (~40 cmx40 cm). The second switch uses the much stronger nonlinearity of a semiconductor optical amplifier (SOA). SOA-based switches can be integrated onto chip-scale optics. The switch we test, the SOA-MZI, fits on a ~0.5 cmxl cm chip. Using the SOA-MZI regenerator, we demonstrate the propagation of 10 Gb/s data over 10,000 km of commercial optical fiber. We also show in simulation that the SOA-MZI's operation may be extended to 40 Gb/s.
by Shelby Jay Savage.
Ph.D.
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Lee, Nancy Yushan. "Performance analysis of single mode optical fiber star networks with reflections". Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/14035.
Abstract (sommario):
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1990.Includes bibliographical references (leaves 53-54).
by Nancy Yushan Lee.
M.S.
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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.
Abstract (sommario):
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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Tebben, Daniel James. "Limitations and Improvement of Subcarrier Multiplexed Systems over Optical Fiber". Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/26968.
Abstract (sommario):
Optical coherent techniques are used to eliminate the power fading found in optical subcarrier multiplexed systems. In a double-side band optical subcarrier system the signal experiences a periodic power fading that is dependent on the fiber dispersion and subcarrier frequency. This power fading is manifested during the direct detection of the subcarrier system using a square-law photodetector. Using a modified optical local oscillator to coherently detect the subcarrier channel this power fading can be eliminated.
An optical local oscillator is centered at the optical carrier in order to perform homodyne detection. However, the local oscillator is modulated by a term equal the subcarrier frequency of interest. This is then a dual-frequency optical local oscillator. By controlling the phases of the local oscillator and the local subcarrier oscillator independently in the homodyne detection scheme, both the phase error and power fading of the detected subcarrier channel can be eliminated. This technique also allows the subcarrier to be selected optically, before the optical-to-electrical conversion.
Analytical and simulation results are given to show the benefits of optical coherent detection in double-sideband subcarrier systems. By eliminating the periodic power loss found in the double-sideband subcarrier system the signal becomes dispersion limited and not power limited. A comparison of double-sideband and single-sideband subcarrier systems is presented. Multiple subcarriers and subcarrier spacing are also investigated for both double sideband and single sideband subcarrier systems.
Optical phase and modulator noise are also considered in the analysis and simulation of coherent detection using a dual frequency optical local oscillator. Since the implementation used to eliminate the power fading is a phase correction based process, the phase noise of both the source and local oscillator lasers must be considered and the technique compared to typical direct and coherent detection techniques. Also, the effects of modulator nonlinearity are simulated for multichannel subcarrier multiplexed systems and comparisons made between the performance of using the dual-frequency local oscillator and typical detection techniques. It is shown that the advantages of the dual-frequency LO are retained in the presence of both phase noise and modulator nonlinearity.Ph. D.
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Tanir, Oryal. "The design and analysis of nodes in a fiber optic based star network (STARNET) /". Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61262.
Abstract (sommario):
STARNET is a fiber optic based network which facilitates the interconnection of distributed Local Area Networks. Configured as a sixteen pointed star topology with a multiprocessor based controller at the center of the star (named the Central Switch). STARNET is capable of scheduling calls from users connected to User Access Nodes located at the points of the star. Messages are passed from one node to another through the Central Switch via duplex fiber optic lines connecting each node to the center.This paper presents a multiprocessor based design of the User Access Node. The hardware and software structure is examined in depth, providing solid guidelines for the physical construction of the unit. The performances of statistical STARNET models using parameters obtained from the design (and three different Central Switch models) are plotted and compared for five different examples of external traffic. The model analysis gives an indication of the expected message delays, supporting the feasibility of the design.
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Zou, Ding, e Ding Zou. "FPGA-Based LDPC Coded Modulations for Optical Transport Networks". Diss., The University of Arizona, 2017. http://hdl.handle.net/10150/622985.
Abstract (sommario):
Current coherent optical transmission systems focus on single carrier solutions for 400Gb/s serial transmission to support traffic growth in fiber-optics communications, together with a few subcarriers multiplexed solutions for the 1 Tb/s serial data rates and beyond. With the advancement of analog-to-digital converter technologies, high order modulation formats up to 64-QAM with symbol rate up to 72Gbaud have been demonstrated experimentally with Raman amplification. To enable such high serial data rates, it is highly desirable to implement in hardware low complexity digital signal processing schemes and advanced forward error correction coding with powerful error correction capability. In this dissertation, to enable high-speed optical communications, we first proposed an efficient FPGA architecture of high-performance binary and non-binary LDPC engines that can support throughputs of multiple Gb/s, which have low power consumption, providing high net coding gains at a target bit-error rate of 10-15. Further, we implement a generalized LDPC coding based rate adaptive binary LDPC coding scheme and puncturing based rate adaptive non-binary LDPC coding scheme, where large number of parameters can be reconfigured in order to cope with the time-varying optical channel conditions and service requirements. Based on comprehensive analysis on complexity, latency, and power consumption we demonstrate that the proposed efficient implementation represents a feasible solution for the next generation optical communication networks. Additionally, we investigate the FPGA implementation of rate adaptive regular LDPC coding combined with up to six high-order modulation formats and demonstrate high net coding gain performance and demonstrated a bit loading algorithm for irregular LDPC coding. Lastly, we present the real-time implementation of a direct detection OFDM transceiver with multi Giga symbols/s symbol rates in a back-to-back configuration.
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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.
Abstract (sommario):
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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Lin, Changyu. "Non-Binary Coded Modulation for FMF-Based Coherent Optical Transport Networks". Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/613281.
Abstract (sommario):
The Internet has fundamentally changed the way of modern communication. Current trends indicate that high-capacity demands are not going to be saturated anytime soon. From Shannon's theory, we know that information capacity is a logarithmic function of signal-to-noise ratio (SNR), but a linear function of the number of dimensions. Ideally, we can increase the capacity by increasing the launch power, however, due to the nonlinear characteristics of silica optical fibers that imposes a constraint on the maximum achievable optical-signal-to-noise ratio (OSNR). So there exists a nonlinear capacity limit on the standard single mode fiber (SSMF). In order to satisfy never ending capacity demands, there are several attempts to employ additional degrees of freedom in transmission system, such as few-mode fibers (FMFs), which can dramatically improve the spectral efficiency. On the other hand, for the given physical links and network equipment, an effective solution to relax the OSNR requirement is based on forward error correction (FEC), as the response to the demands of high speed reliable transmission. In this dissertation, we first discuss the model of FMF with nonlinear effects considered. Secondly, we simulate the FMF based OFDM system with various compensation and modulation schemes. Thirdly, we propose tandem-turbo-product nonbinary byte-interleaved coded modulation (BICM) for next-generation high-speed optical transmission systems. Fourthly, we study the Q factor and mutual information as threshold in BICM scheme. Lastly, an experimental study of the limits of nonlinearity compensation with digital signal processing has been conducted.
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Li, Jonathan Chi Fai. "Eye closure penalty based signal quality metric for intelligent all-optical networks /". Connect to thesis, 2009. http://repository.unimelb.edu.au/10187/7047.