Dissertations / Theses on the topic 'New Generation Passive Optical Network'

Mestrado em Engenharia Electrónica e Telecomunicações
A Internet está a ter um papel cada vez mais activo no quotidiano actual. As exigências de tráfego estão a aumentar consideravelmente mais do que a receita disponivel, sendo que se torna visível a extrema necessidade por servicos de banda larga. Recentemente, os operadores de telecomunicações tem demonstrado um vasto interesse em providenciar serviços a clientes residenciais, usando Redes Ópticas Passivas (PON). Este forte investimento levou ao desenvolvimento de vários standards, estando actualmente a ser desenvolvida a nova geracão da rede. O novo objectivo é bastante claro – NGPON2 deve superar as tecnologias anterioes relativamente à compatibilidade ODN, capacidade, largura de banda e custo-eficiência. Após vários estudos, em Abril de 2012, FSAN ((Full Service Access Network) definiu TWDM (Time- Wavelength Division Multiplexing) como sendo a solução mais atractiva para preencher os requisitos necessários. Em Março de 2013, foi aprovada a norma ITU-T G.989.1 endereçando novos planos de comprimentos de onda, de acordo com as exigências dos operadores. O requisito mais importante para esta nova rede de acesso centra-se em garantir uma possível co-existência com as redes PON já desenvolvidas. Para esse efeito, torna-se essencial uma nova alocação de espectro e posteriores estudos de interferência, garantindo, assim, a preservação de todos os sistemas. No âmbito do referido acima, o presente documento expôe inicialmente um estudo acerca da nova tecnologia TWDM, incluindo caracteristicas gerais e suas limitações. Foram obtidos, para tal, resultados experimentais e simulados. Posteriormente, é efectuado um estudo da tecnologia TWDM em co-existência com redes PONs anteriores e, também, com sinais modulados com diferente formatos. Estes cenários tem o propósito de observar os efeitos gerados no seu desempenho. Alguns parâmetros, como espaçamento entre canais, potência de transmissão e taxas de transmissão de bits foram tidos em consideração. O objectivo é criar uma única rede heterogénea onde vários formatos de alta transmissão de dados co-existem, por forma a optimizar e definir a máxima ocupação da rede de acesso de nova geração.
The Internet is increasingly becoming part of everyday life. Once the traffic demands are growing much more rapidly than the available revenue, it is visible the gradual increase of the need for broadband services. In recent years, telecom operators have shown a great interest in providing various services to residential customers, using the Passive Optical Network (PON) topology. This strong investment has led to several standards in order to achieve the potential subscribers and nowadays is being developed the next generation. The future goal is clear - NGPON2 must overcome previous technologies in ODN compatibility, capacity, bandwidth and cost-efficiency. After several studies, in April 2012, FSAN (Full Service Access Network) defined TWDM (Time-Wavelength Division Multiplexing) as the more attractive solution to fulfill the necessary requirements. On March 2013, was approved the ITU-T G.989.1 recommendation addressing possible wavelength plans, according operator’s needs. The most important requirement for this new access generation is to provide an environment of coexistence with the legacy PON and others. In this order, it is necessary new allocation in the spectrum and further interference studies, to preserve all the systems intact. In this scope, the following document presents a study over the new technology TWDM separately, including general features and limitations. Both simulated and experimental results were obtained. Afterward, it is introduced within several coexistence scenarios, with the legacy and signals with different modulation formats, to observe the effect created on its performance. Were taken into account some parameters as channel spacing, transmitted power and high bit rates. The aim is to create a heterogeneous network with high data rate formats coexisting in the same access network to study and help defining the next generation max occupancy of a given network.

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)

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.

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.

Doutoramento em Engenharia Eletrotécnica - Telecomunicações
The work presented herein, studies Next Generation Optical Access Networks (NG-OAN) economically (e.g. energy consumption) and technologically (e.g. rate, reach and dedicated/shared bandwidth). The work is divided into four main topics: energy efficiency in optical access architectures, novel spectrally efficient Long-Reach Passive Optical Networks (LR-PON), crosstalk impacts in heterogeneous and homogenous access networks and hybrid optical wireless transmissions. We investigate the impact of user profiles, optical distribution network topologies and equipment characteristics on resource sharing and power consumption in LR-PON. To have a clear vision on the energy consumption evolution of each part of NG-OAN, a model is proposed to evaluate the energy efficiency of optical access technologies. A spectrally efficient bidirectional Ultra-Dense Wavelength Division Multiplexing (UDWDM) PON architecture is developed using Nyquist shaped 16-ary quadrature amplitude modulation, offering up to 10 Gb/s service capabilities per user or wavelength. Performance of this system in terms of receiver sensitivity and nonlinear tolerance under different network transmission capacity conditions are experimentally optimized. In bi-directional transmis-sion, using frequency up/down-shifting of Nyquist pulse shaped signal from optical carrier, a full bandwidth allocation and easy maintenance of UDWDM networks as well as reduction of Rayleigh back-scattering are achieved. Moreover, self-homodyne detection is used to relax the laser linewidth requirement and digital signal processing complexity at the optical network unit. Simplified numerical model to estimate the impact of Raman crosstalk of multi-system next generation PONs in video overlay is proposed. Coexistence of considered G.98X ITU-T series and coherent multi-wavelength systems is considered and assessed. Additionally, the performances of bidirectional hybrid optical wireless coherent PONs over different optical distribution network power budgets and hybrid splitting ratios are evaluated.
O trabalho aqui apresentado estuda redes óticas de acesso de próxima geração (NG-OAN) nas vertentes económica (consumo de energia) e tecnológica (taxa, alcance e largura de banda dedicada/partilhada). O trabalho está dividido em quatro grandes temas de investigação: a eficiência energética em arquiteturas de acesso ótico, as redes óticas passivas de longo alcance (LR-PON) com nova eficiência espetral, o impacto da diafonia em redes de acesso heterogéneas e homogéneas e as transmissões ópticas híbridas com tecnologias sem fio. Investiga-se o impacto dos perfis dos utilizadores, as tipologias da rede de distribuição ótica, as características do equipamento de partilha de recursos e o consumo de energia em LR-PON. Para se ter uma visão clara sobre o consumo de energia de cada parte das NG-OAN, é proposto um modelo para avaliar a eficiência energética das tecnologias de acesso óticas. Desenvolve-se uma arquitetura PON bi-direcional com elevada eficiência espetral, recorrendo a multiplexagem por divisão de comprimento de onda ultra-densa (UDWDM), modulação de amplitude em quadratura com formato de impulso de Nyquist, oferecendo até 10 Gb/s por utilizador/comprimento de onda. O desempenho deste sistema em termos de sensibilidade do recetor e da tolerância à resposta não linear do canal de comunicação, sob diferentes condições de transmissão, é avaliado experimentalm-ente. Em transmissão bi-direcional, utilizando desvio de frequência (cima/baixo) do impulso com formato de Nyquist relativo à portadora ótica conseguiu-se uma alocação de largura de banda completa e uma manutenção mais simplificada de redes UDWDM, bem como a redução do espalhamento de Rayleigh. Além disso, a deteção auto-homodina é usada para relaxar o requisito de largura de linha do laser e a complexidade do processamento digital de sinal nas unidades da rede ótica. Propõe-se um modelo numérico simplificado para estimar o impacto da diafonia de Raman em sistemas PON de próxima geração, com sobreposição do sinal de vídeo. É analisada a coexistência da série G.98X ITU-T e são considerados e avaliados sistemas coerentes multi-comprimento de onda. Adicionalmente avaliam-se os desempenhos de PONs bi-direcionais híbridas, considerando tecnologia coerente e propagação por espaço livre, para diferentes balanços de potência e taxas de repartição na rede ótica de distribuição.

Orientador: Rangel Arthur
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Tecnologia
Made available in DSpace on 2018-08-22T06:36:42Z (GMT). No. of bitstreams: 1 Hoshino_FelipeKojiGodinho_M.pdf: 3730881 bytes, checksum: d6cd57d6d8286fe95b3166c35de77d73 (MD5) Previous issue date: 2013
Resumo: O aumento exponencial no tráfego mundial de dados tem imposto inúmeros desafios para os sistemas de telecomunicações. Há um compromisso entre o interesse das operadoras de telecomunicações, de aumentar a receita líquida, e dos clientes, de aumentar a taxa de transmissão de dados. Com isso, diversas soluções têm sido discutidas no âmbito das comunicações ópticas. Uma das propostas estudadas é a aplicação mais intensa do processamento digital de sinais. Dessa forma, neste trabalho foi estudado e simulado o uso da modulação OFDM (Orthogonal Frequency Division Multiplexing) nas redes ópticas de nova geração. Também foi simulado um modem OFDM em linguagem VHDL (Very High Speed Integrated Circuit Hardware Description Language) sendo esta uma etapa do projeto de novos equipamentos. Como prova de conceito, analisou-se o desempenho de redes ópticas por meio do software OptiSystem. De maneira geral, os resultados obtidos foram satisfatórios para demonstrar a viabilidade da modulação OFDM em redes ópticas de nova geração
Abstract: The exponential increase in global data traffic has imposed many challenges for telecommunication systems. There is a trade-off between the interest of telecom operators to increase the net revenue and the customers to increase the transmission data rate. Several solutions have been discussed in optical communications field. One approach is the more intense application of the digital signal processing. Thus, in this work is presented a review and simulations of OFDM modulation (Orthogonal Frequency Division Multiplexing) in the next generation networks. It was also simulated a OFDM modem in VHDL (Very High Speed Integrated Circuit Hardware Description Language) which for a new equipment design. The performance of optical networks has been examinated with OptiSystem software as o proof of concept. In general, the results obtained were satisfactory to show the feasibility of OFDM modulation in the next generation networks
Mestrado
Tecnologia e Inovação
Mestre em Tecnologia

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.

The continuous evolution of the optical communication technology in the last few years has allowed the growing users demand for higher bandwidth to be satisfactorily attended. This new demand is mainly attributed to the growing popularity of bandwidth-intensive networking applications, such as Internet protocol television (IPTV), high-definition television (HDTV), e-learning, e-health, super high-definition (SHD) class digital movies, and e-culture based on 3-D full-HD video. These applications will eventually require differentiated service types and diversified data rates. As a result, capability of supporting differentiated-quality of service (QoS) and multirate transmission are becoming a challenge for future optical networks. Among many multiplexing techniques, optical code-division multiple-access (OCDMA) constitutes a potential candidate for next generation optical networks, particularly due to features like asynchronous operation, simplified network control, easy addition of new users, and possibility of differentiated-QoS at the physical layer. The performance of this access technique is mainly limited by multiple-access interference (MAI). Although in multirate, multiservice OCDMA systems MAI is considered to be binomially distributed, others probability distributions for the MAI analyzes and consequently the bit error rate (BER) have been used as an approximation. In this context, this dissertation proposes a new formalism to evaluate the BER performance of 1-D and 2-D multirate, multiservice OCDMA systems considering MAI as binomially distributed, resulting in a more accurate BER expression. Also, the proposed approach does not require knowledge a priori of the generated code sequences themselves, which means that the system performance analysis is achieved more easily using only the code parameters. Furthermore, a multirate OCDMA system employing 1-D optical orthogonal code (OOC) and 2-D optical fast frequency hopping (OFFH) codes is also investigated. A performance comparison in terms of BER for the OOC-based system assuming both Poisson and binomial distribution for the MAI is investigated. A further comparison of an OFFH-based multirate system assuming both gaussian and binomial distribution for the MAI is also analyzed. It is shown that BER performance in multirate scenarios can be overestimated or underestimated by many orders of magnitude depending on the assumed distribution for the MAI and on the number of simultaneous users. Moreover, it is presented for the first time a hybrid OCDM/WDM optical packet switch capable of supporting multirate and differentiated-QoS transmission. The architecture of the proposed multirate switch and its performance in terms of packet loss probability are also presented. Finally, it is shown that using a gaussian or Poisson distribution for the MAI might not be appropriate for a reliable BER estimate, since they are not acceptable approximations to assess the performance of multirate, multiservice systems with good accuracy.
A contínua evolução da tecnologia de comunicações ópticas observada nos últimos anos vem possibilitando atender a crescente demanda dos usuários por maior largura de banda. Esta nova demanda é atribuída principalmente à popularidade crescente de aplicações de banda larga, tais como TV por protocolo de Internet (IPTV), televisão de alta definição (HDTV), ensino online, e-saúde, filmes digitais de super alta definição (SHD) e e-cultura baseado em vídeo 3-D full-HD. Esta vasta gama de aplicações acabará por necessitar de tipos de serviços diferenciados e taxas de transmissão de dados diversificadas. Como resultado, capacidades de suportar diferenciamento de qualidade de serviço (QoS) e transmissão de múltiplas taxas estão se tornando um desafio para as redes ópticas futuras. Dentre muitas técnicas de multiplexação existentes, OCDMA constitui-se em um candidato potencial para as redes ópticas de próxima geração, particularmente devido a características como operação assíncrona, controle de rede simplificada, fácil adição de novos usuários, e também possibilidade de QoS diferenciado na camada física. O desempenho desta técnica de acesso múltiplo é limitado principalmente por interferência múltipla de acesso (MAI). Embora em sistemas OCDMA de múltiplas taxas e multiserviços a MAI deva ser considerada binomialmente distribuída, outras distribuições de probabilidade para a análise da MAI e, consequentemente, da BER têm sido utilizadas como uma aproximação. Neste contexto, este trabalho propõe um novo formalismo para avaliar o desempenho da BER de sistemas OCDMA 1-D e 2-D de múltiplas taxas e multisserviços considerando a MAI como binomialmente distribuída, o que resulta em uma expressão mais precisa para a BER. Além disso, o método proposto neste trabalho não requer conhecimento, a priori, das sequências de códigos geradas, o que significa que a análise do desempenho do sistema é obtida mais facilmente utilizando apenas os parâmetros do código. Um sistema OCDMA de múltiplas taxas empregando códigos 1-D OOC e 2-D OFFH será também investigado. Uma comparação do desempenho em termos de BER para o sistema baseado em OOC supondo tanto a distribuição de Poisson quanto a binomial para a MAI é investigada. De forma análoga, uma comparação para o sistema de múltiplas taxas baseado em OFFH supondo desta vez tanto a distribuição gaussiana quanto a binomial para a MAI também é analisada. É mostrado que a BER em cenários de múltiplas taxas pode ser superestimada ou subestimada em várias ordens de grandeza, dependendo da distribuição suposta para a MAI e do número de usuários simultâneos no sistema. Além disso, é apresentado pela primeira vez um switch óptico híbrido de pacotes OCDM/WDM capaz de prover transmissões de múltiplas taxas e serviços diferenciados. A arquitetura do switch proposto e seu desempenho em termos de probabilidade de perda de pacotes também são apresentados. Finalmente, é mostrado que o uso da distribuição gaussiana ou poissoniana para a MAI pode não ser apropriado para uma estimativa confiável de BER, uma vez que não são aproximações aceitáveis para avaliar o desempenho de sistemas de múltiplas taxas e multiserviços com boa precisão.

碩士
國立交通大學
顯示科技研究所
100
In my thesis, we had studied three issues which are significant for passive optical network (PON). They are protection PON, radio over fiber and the power consumption respectively. In the chapter two, we propose two self-healing fiber protection PON and show up our scheme and the experiment result. We also calculate the reliability and compare it with other protection system. In the chapter three, we use three Mach-Zehnder modulators to create the optical wire and wireless signal with a high spatial efficiency, explaining the principle of our architecture and how we demodulate the signal with the arranged eye diagram. In chapter four, based on the Ethernet PON, we do the power consumption simulation about the future 40Gb/s PON transmission and calculate the power consumption. The final chapter is my conclusion and the future work.

碩士
國立交通大學
光電工程研究所
101
In order to meet the demand of broadband multimedia services in the near future, FSAN (Full Service Area Network) selected TWDM as a primary solution to next-generation passive optical network (NGPON), named NGPON2, which can provide 40Gbps capacity to support 1-Gbps data rate for each optical network unit (ONU). After NG-PON2, 100Gbps capacity is most likely seen as the next generation standard. And Optical OFDM PON with intensity modulation and direction (IMDD), which offer high spectral efficiency and flexible bandwidth allocation, is very suitable for 100-Gbps system. A cost-effective 10-GHz IMDD OFDM system has already achieved 40-Gbps capacity over 100km SSMF transmission. However, it needs to further improve the data rate to 100-Gbps. This thesis presents a cost-effective system combining multicarrier with IMDD OFDM system, and theoretically compares the multicarrier conversion efficiency of PM and MZM. We demonstrate a multicarrier IMDD OFDM system using phase modulator and successfully reach 100-Gbps over 20-km SSMF transmission.

碩士
國立中山大學
電機工程學系研究所
95
Due to the advances in content distribution and data center technologies, the traffic inside metropolitan area network (MAN) becomes more and more distributed. The current MAN architecture that only plays the role of bridge becomes insufficient to handle such new traffic patterns. Hence, the demand for a new MAN architecture is inevitable. It is expected to be both efficient and cost-effective. In this thesis, we proposed Optical Buffer Ring (OBR) as the solution of next generation MAN. It combines both OBS''s low end-to-end delay and RPR''s low loss rate. And compared to more advanced network architectures based on optical packet switching, OBR is of lower cost and thus more feasible in the near future. To evaluate the performance of OBR, we conducted simulation study over large set of parameters. According to the results, the performance of OBR indeed coincides with our expectation. Furthermore, OBR scales better than both OBS and RPR in that the end-to-end delay of OBR decreases as network size increases while the loss rate increases little with network size. Index Terms－MAN, WDM, OBS, OBR, RPR, HORNET, LightRing, Diffserv, optical packet switching.

碩士
國立中興大學
電機工程學系所
99
Due to the ever increasing demands on data communication bandwidth for services such as High Definition video and audio broadcast, on-line gaming, distance learning, and so on, traditional wired networks have failed to provide satisfactory services. In face of these emerging applications requiring high-data rate, real-time and multi-users services, Next-generation passive optical networks (NG-PONs), due to its spectral efficiency and cost effective implementation, is regarded as a promising solution. 　　In this thesis, the baseband transceiver design for the NG-PON is investigated. The NG-PON platform can be divided into the electrical and the optical sections. For the optical section, we assume an IMDD (intensity modulation and direct detection) optoelectronics architecture is adopted. No optical amplification and chromatic dispersion compensation measures are employed to reduce the system cost on the optical section. Instead, the optical network impairments are tackled in the electrical domain where the DSP solution is considered much less expensive than the counterpart in the optical domain. To further reduce the bandwidth, which is proportional to the cost of the opto-electrical conversion devices such as laser diode and photon detector, we adopt an OFDM architecture to enhance the spectrum efficiency. The OFDM architecture also provides an easy solution to the effects of chromatic dispersion, polarization mode dispersion and other fiber distortion. A uniform 64QAM modulation format is used in each tone and a data rate as high as 8.667Gbps can be delivered occupying a frequency bandwidth less than 2GHz. Starting with a network specs, the link budget is first calculated and baseband performance specs are derived accordingly. The system operates at a sampling frequency of 4GHz and an 8-way parallel baseband architecture working at 500MHz is developed to meet the computing demands. In the baseband module designs, we develop efficient parallel synchronization schemes covering packet detection, FFT boundary detection, sampling frequency offset compensation. A 8-way parallel 64-point FFT processor and a simple one-tap equalizer performed in the frequency domain using zero forcing strategy are also developed. The developed baseband transceiver design is implemented on a Xilinx Virtex 5 LTX rapid prototyping platform equipped with high speed serial links RocketIO. The implementation results show that the design can operate at 331MHz and the critical path delay is bounded by the FFT module. As FFT is the most computation intensive module in the baseband design, it is further implemented in chip using UMC 90nm process. The design occupies a 1.64 x 1.64 mm2 chip area and consumes 54 mW at the clock rate of 500 MHz.

碩士
國立臺灣海洋大學
光電科學研究所
106
Next generation technology, NG-PON2 , can provide integrated network services, for example, 5G the backhaul connection for wireless communication. However, NG-PON2 has not entered the commercial phase because of many technical problems. This thesis investigates related technical issues by prototyping of the NG-PON2 with focus on the thermally tuned mechanisms. For the case of transmitter, by controlling the temperature of the DFB LD, we successfully demonstrate the tuning of wavelength for C-band channels, 1532.68 nm, 1533.47 nm, 1534.25 nm, and 1535.04 nm, and for the receiver demonstrate, the pass-band transmission spectrum is adjusted to ITU-defined downstream wavelengths, i.e., 1959.34 nm, 1597.19 nm, 1598.04 nm, and 1598.89 nm, through controlling the temperature of the etalon filter integrated on the receiver. In the stability evaluation of the transceiver module operation, although the ambient temperature causes wavelength drift of the transceiver module, the wavelength drift can be compensated by adjusting the controlling temperature with additionl compensation temperature. After compensation, we achieve about ±1 GHz for the transmitter and ±5 GHz for the receiver in wavelength control under different operating temperatures. For the evaluation of NG-PON2 wavelength switching speed, this study attempts to achieve class 3 (25 ms~1 s) control by a modified PID algorithm. Switching time of the transmitter can reach about 300 ms (±5 GHz) . However, the receiver settling time is longer than 1 s (about 15 s) . Since the ramp-up time to the target temperature is less than 1 s, we believe further improvement to reach switching time less than 1 s is possible. In order to evaluate the wavelength drift of the transmitter under burst mode operation, we use a signal generator to simulate different burst periods and observes the wavelength drift of the transmitter within the burst transmission period. After the first sampling point (about 20 ns) , due to the thermal effect, the burst duration of 40 μs, 59 μs, 88 μs, the wavelength drifts 13 GHz, 11 GHz, 8 GHz, respectively.

This document presents the developed work, in the scope of the implementation of next generation passive optical networks (PON), options and feasibility assessment. With the development of the Fifth Generation of Mobile Networks (5G), new challenges arose for PON networks, namely: a cost competitive solution, with bit rates of 25 Gbps and 50 Gbps. Through time, the growth and increase of quality of service to the final consumer have been pushing the necessity of development of new solutions and technologies related to PON networks. Considering several aspects such as: increase of bit rates, cost minimization and coexistence with previous technologies, NG-PON2 (Next Generation Passive Optical Network 2) was created and developed. Therefore, this thesis focus on the study of proposed 25 Gbps implementations, simulating different technological approaches, for the transmitter, involving EML (Externally Modulated Laser) and DML (Directly Modulated Laser), and receivers, PIN (Positive Intrinsic Negative) and APD (Avalanche Photodiode). Thus, the limits and advantages of each solution were accessed. The modeling of real 25 Gbps receivers was made, with success. Additionally, a study of NG-PON2 was conducted and laboratory tests were done involving transceivers of this technology. Finally, a characterization of a SFP28 transceiver was made, this one with a characteristic bit rate of 25Gbps. This work, demonstrates the viability of the use of O-band wavelengths and DML transmitters with bit rate of 25 Gbps and SMF (Single Mode Fiber) reach of 40 km. Highlighting the importance of the biasing and modulation currents and ER (Extinction Ratio), in the performance optimization. Also the laboratory characterization of a SFP28 transceiver was done with success.
Este documento apresenta o trabalho realizado, no âmbito da implementação de redes óticas passivas (PON) de próxima geração, opções tecnológicas e avaliação de viabilidade. Com o desenvolvimento da Quinta Geração de Redes Móveis (5G), surgiram novos desafios para as redes PON, nomeadamente: uma implementação de custo competitivo, com ritmos de transmissão a tender para 25 Gbps e 50 Gbps. Ao longo do tempo, o crescimento e aumento da qualidade de serviços tem implicado a necessidade de desenvolvimento de novas soluções e tecnologias em redes PON. Tendo em vista vários aspetos como: o aumento do ritmo de transmissão, minimização do custo e coexistência com tecnologias anteriores, a norma NG-PON2 (Next Generation Passive Optical Network 2) foi criada e desenvolvida. No seguimento, esta dissertação foca-se no estudo de implementações de PON a 25 Gbps, com a simulação de diferentes tecnologias para os transmissores, nomeadamente EML (Externally Modulated Laser), DML (Directly Modulated Laser) e recetores, PIN (Positive Intrinsic Negative) e APD (Avalanche Photodiode). Desta maneira, pretendeu-se entender os limites e vantagens de cada opção. A modelização de recetores reais para 25 Gbps, foi feito com sucesso. Adicionalmente fez-se um estudo da tecnologia NG-PON2 e testes laboratoriais com transceivers da mesma. Por fim realizou-se a caracterização de um transceiver SFP28, com ritmo de transmissão de 25Gbps. Este trabalho demonstra a viabilidade do uso de comprimentos de onda da O-band e transmissores DML a velocidades de 25 Gbps com alcance de 40 km de SMF (Single Mode Fiber). Demonstrando a importância da escolha de parâmetros como as correntes de polarização e modulação e ER (Extintion Ratio), para otimização do desempenho do sistema. Também se caracterizou laboratorialmente, com sucesso, um transceiver SFP28.
Mestrado em Engenharia Eletrónica e Telecomunicações

As comunicações óticas têm demonstrado ser a tecnologia capaz de satisfazer a crescente procura do consumidor por serviços e produtos, através das redes de comunicação, procurando tecnologias com maior largura de banda. Desse modo, esta procura estimula o desenvolvimento de novas soluções eficientes e economicamente viáveis. As comunicações óticas na rede de acesso utilizam Passive Optical Network (PON), com fibra ótica desde o Optical Line Terminal (OLT) até aos consumidores finais (Optical Network Unit (ONU)). As redes óticas passivas de próxima geração pressupõem o uso de multiplexagem no comprimento de onda para aumentar a sua capacidade de transmissão. Neste cenário são requeridas funcionalidades de flexibilidade e ajuste dinâmico nas ONUs, sendo valorizadas abordagens de baixo custo. Para tal, as soluções de filtragem, a serem usadas nos transceptores das ONUs, desempenham um papel fulcral na execução desta funcionalidade. Nesse sentido, estas soluções de filtragem podem ser implementadas através de filtros de filme fino. Estes demarcam-se por permitirem implementar a resposta espetral desejada, e proceder à sintonia através da variação de temperatura e/ou pelo desvio do ângulo de incidência. Aliado às suas características, podem ser integrados oticamente com circuitos óticos integrados e produzidos em grande escala e a baixo custo. Desse modo, os principais objetivos desta dissertação são o estudo e modelização de TFF e o desenvolvimento de uma solução de filtragem TFF, conforme os requisitos impostos pela norma NG-PON2.
Optical communications have demonstrated to be the technology capable of satisfying the growing need of consumers for services and products, through communication networks, searching technologies with greater bandwidth. This search stimulates the development of new e_cient and economically viable solutions. The optical communications on the access network use PON, with optic _ber from the OLT to the _nal consumers (ONU). The next generation passive optic networks assume the usage of multiplexing on the wavelength to increase its transmission capacity. In this scenario, the functionalities of exibility and dynamic tuning of the ONUs are required, being low cost approaches preferable. To this end, the _lter solutions, to be used in the transceivers of the ONUs, play a major role in the execution of this functionality. For this goal, these solutions can be implemented through thin _lm _lters. These stand out for allowing the desired spectral response to be implemented and proceed to the tuning by the variation of temperature and/or deviation of the incidence angle. In combination with its characteristics, can be integrated optically with integrated optic circuits and be produced on a large scale and at a low cost. This way, the main goals of this dissertation are the study of the TFF modulation and the development of a TFF _lter solution, per the requirements imposed by the NG-PON2 standard.
Mestrado em Engenharia Eletrónica e Telecomunicações