Download or read book Performance Improvement of SS WDM Passive Optical Networks Using Semiconductor Optical Amplifiers Modeling and Experiment written by Walid Mathlouthi and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les sources incohérentes sont proposées comme alternatives aux lasers stabilisés en longueur d'onde pour réduire le coût des réseaux optiques passifs utilisant le multiplexage par longueur d'onde découpée dans le spectre (SS-WDM PONs). À cause de leur nature incohérente, ces sources génèrent au récepteur un large bruit d'intensité. Ce bruit limite l'efficacité spectrale et/ou le taux binaire pouvant être achevé. Cette thèse étudie l'utilisation des amplificateurs optique à semi-conducteur SOAs pour nettoyer le bruit d'intensité. De plus, lors de cette thèse, nous explorons les outils numériques et expérimentaux qui nous permettent d'analyser les performances des SOAs dans le cadre de systèmes de communication multi-canaux, incluant le SS-WDM. Nous présentons des modèles mathématiques pour le bruit d'intensité, ce bruit étant celui qui limite les performances des systèmes de communication utilisant des sources incohérentes. Nous discutons les dynamiques complexes des SOAs et présentons les équations qui gouvernent l'évolution des porteurs de charges dans ces amplificateurs. Nous identifions et soulignons l'effet des paramètres les plus importants, qui affectent le processus ainsi que la dynamique de nettoyage du bruit d'intensité. Nous passons en revue, les différentes techniques de nettoyage de bruit avec les SOAs, qui ont démontré les meilleurs résultats connus. De plus, nous effectuons une revue de littérature poussée pour ce qui a attrait au problème de post-filtrage lorsque le SOA est placé au transmetteur, avant la modulation. Notre première contribution pendant ce travail de recherche est de démontrer, en utilisant l'intermodulation de gain d'un SOA au récepteur pour convertir le signal incohérent en laser cohérent, une amélioration significative du taux d'erreur binaire BER. Cette méthode est spectralement efficace, d'autant plus qu'elle ne souffre point la limitation occasionnée par le post-filtrage au récepteur. En contre partie elle nécessite un ample budget de puissance qui doit assurer une saturation suffisante de l'amplificateur au récepteur. Une source laser est aussi nécessaire au récepteur. Ceci est un inconvénient, même si une telle source n'ait pas besoin d'une quelconque stabilisation. Pour contourner le problème causé par le post-filtrage quand le SOA est au transmetteur, nous proposons un nouveau récepteur pour les systèmes de communication WDM, qui permet de mieux garder le nettoyage de bruit, et ce malgré le filtrage optique au récepteur. La nouvelle méthode consiste en un détecteur balancé utilisé au récepteur: d'un bord, tous les canaux sont détectés sans distinction. De l'autre, le signal désiré est bloqué pendant que tous les autres canaux sont détectés. Avec cette méthode, il est facile de saturer l'amplificateur pour une meilleure suppression de bruit tout en évitant en grande partie la dégradation causé par le post-filtrage. Nous avons expérimentalement démontré un système WDM dense de 8 x 10 Gbps avec une source incohérente et un SOA en saturation. Une autre contribution originale de ce travail est le développement d'un outil de simulation pour les SOAs qui est numériquement plus efficace et léger que les modèles connus à ce jour. Nous avons donc développé un modèle théorique simple, pouvant être implémenté par diagramme block, dans le but de simuler les performances des hens de communications WDM. Notre modèle démontre une bonne concordance avec les résultats expérimentaux ainsi qu'une diminution de temps de calcul de l'ordre de 20 fois. Finalement, lors de la dernière partie de ces travaux, nous nous sommes occupés de mesurer, de façon précise, le temps de recouvrement du gain dans un SOA. Le temps de recouvrement des porteurs dans un SOA est un des paramètres les plus importants qui sont à l'origine du phénomène de nettoyage de bruit et qui régissent le comportement ainsi que les dynamiques de l'amplificateur. Nous avons étudié en particulier, la dépendance de ce temps de recouvrement r de la longueur d'onde. Pour le SOA utilisé lors de notre étude expérimentale, nous avons démontré que r dépendait de la longueur d'onde de façon similaire au spectre de gain. Ces mesures ont été possibles grâce au développement d'un nouveau dispositif de mesure pompe/sonde, qui permettait de mesurer le recouvrement du gain pour une pompe et une sonde à la même longueur d'onde et ayant le même état de polarisation.

Download or read book Numerical Study of Semiconductor Optical Amplifiers for Passive Optical Networks written by Lin Liu and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The motivation of this thesis is to better understand the characteristics of Semiconductor Optical Amplifiers (SOAs) and their use in the Passive Optical Networks (PON), particularly in packet equalisation. Following an introduction to physical principles and structure of SOAs the architecture of optical communication system especially PON is explained. The basic characteristics and key applications of SOAs are then discussed. In this study, the modelling of SOAs has been achieved at both system and device levels. In terms of high efficient system level SOA model, both co-propagation and counter-propagation models are employed to study the cross gain modulation of SOAs. The co-propagation system model has also been used to study the gain compression effect of SOAs. The direct modulation frequency response of a SOA is also investigated numerically. Alternatively, the detailed device level SOA model, which includes a wideband material gain coefficient taking the intraband relaxation effect into account and an efficiency-improved steady state algorithm, is proposed to study the DC characteristics of SOAs. Based on the detailed device level SOA model, the numerical model for the adjustable gain-clamped SOA (AGC-SOA) has been proposed to investigate both the steady state operation and the case where the gain of the AGC-SOA is dynamically modulated. Through theoretical analysis and experimental investigation, this study demonstrated that the gain of AGC-SOA would be dynamically modulated in response to the changes in packet amplitude in PONs.

Download or read book Advances in Optical Amplifiers written by Paul Urquhart and published by BoD – Books on Demand. This book was released on 2011-02-14 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical amplifiers play a central role in all categories of fibre communications systems and networks. By compensating for the losses exerted by the transmission medium and the components through which the signals pass, they reduce the need for expensive and slow optical-electrical-optical conversion. The photonic gain media, which are normally based on glass- or semiconductor-based waveguides, can amplify many high speed wavelength division multiplexed channels simultaneously. Recent research has also concentrated on wavelength conversion, switching, demultiplexing in the time domain and other enhanced functions. Advances in Optical Amplifiers presents up to date results on amplifier performance, along with explanations of their relevance, from leading researchers in the field. Its chapters cover amplifiers based on rare earth doped fibres and waveguides, stimulated Raman scattering, nonlinear parametric processes and semiconductor media. Wavelength conversion and other enhanced signal processing functions are also considered in depth. This book is targeted at research, development and design engineers from teams in manufacturing industry, academia and telecommunications service operators.

Download or read book Optically Amplified WDM Networks written by John Zyskind and published by Academic Press. This book was released on 2011-01-26 with total page 483 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the advent of wavelength routing and dynamic, reconfigurable optical networks, new demands are being made in the design and operation of optical amplifiers. This book provides, for the first time, a comprehensive review of optical amplifier technology in the context of these recent advances in the field. It demonstrates how to manage the trade-offs between amplifier design, network architecture and system management and operation. The book provides an overview of optical amplifiers and reconfigurable networks before examining in greater detail the issues of importance to network operators and equipment manufacturers, including 40G and 100G transmission. Optical amplifier design is fully considered, focusing on fundamentals, design solutions and amplifier performance limitations. Finally, the book discusses other emerging applications for optical amplifiers such as optical networks for high data rate systems, free space systems, long single span links and optical digital networks. This book will be of great value to R&D engineers, network and systems engineers, telecommunications service providers, component suppliers, industry analysts, network operators, postgraduate students, academics and anyone seeking to understand emerging trends in optical networks and the consequent changes in optical amplifier design, features and applications. Provides an in depth and focused review of the new reconfigurable network architecture and its impact on optical amplifiers Addresses 40G and 100G transmission and networking Written by experts in the field with deep technical knowledge and practical experience of commercial practice and concerns

Download or read book Semiconductor Optical Amplifiers written by Niloy K. Dutta and published by World Scientific. This book was released on 2013 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: This invaluable look provides a comprehensive treatment of design and applications of semiconductor optical amplifiers (SOA). SOA is an important component for optical communication systems. It has applications as in-line amplifiers and as functional devices in evolving optical networks. The functional applications of SOAs were first studied in the early 1990''s, since then the diversity and scope of such applications have been steadily growing. This is the second edition of a book on Semiconductor Optical Amplifiers first published in 2006 by the same authors. Several chapters and sections representing new developments in the chapters of the first edition have been added. The new chapters cover quantum dot semiconductor optical amplifiers (QD-SOA), reflective semiconductor optical amplifiers (RSOA) for passive optical network applications, two-photon absorption in amplifiers, and, applications of SOA as broadband sources. They represent advances in research, technology and commercial trends in the area of semiconductor optical amplifiers.Semiconductor Optical Amplifier is self-contained and unified in presentation. It can be used as an advanced text by graduate students and by practicing engineers. It is also suitable for non-experts who wish to have an overview of optical amplifiers. The treatments in the book are detailed enough to capture the interest of the curious reader and complete enough to provide the necessary background to explore the subject further.

Download or read book Linear and Nonlinear Semiconductor Optical Amplifiers for Next Generation Optical Networks written by René Bonk and published by KIT Scientific Publishing. This book was released on 2014-05-12 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, semiconductor optical amplifiers (SOAs) are studied with a view to linear and nonlinear applications in next-generation optical networks. Quantum-dot SOAs can be optimized for linear amplification of signals with different modulation formats and multiplexing techniques. Conversely, bulk SOAs can be easily optimized for operation in the nonlinear regime. However, due to the fast carrier recovery times in QD SOAs we also look into nonlinear applications with these devices.

Download or read book Improved Techniques for Passive Optical Networks written by Douglas Ryan Tourtillott Jorgesen and published by . This book was released on 2010 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work in this thesis introduces a variety of techniques that can be used to improve the performance of previous state of the art passive optical networks (PONs). These networks will be of increasing importance as increasing bandwidth demand drives the penetration of optical fiber into access networks. PONs require novel design techniques due to their bidirectional nature and tight cost requirements. In this thesis improvements are proposed in three categories: filtering of bidirectional noise; novel modulation techniques; and use of non-traditional low cost devices (specifically vertical cavity surface emitting lasers (VCSELs)). High pass filtering (HPF) is shown to reduce the impact of bidirectional Rayleigh noise, which is dominant in PONs. It is demonstrated that under certain circumstances Rayleigh noise immunity is improved by up to 10 dB with proper selection of an HPF. A model to predict the effects of baseline wander caused by HPF is developed and experimentally validated. This model is combined with an existing Rayleigh noise model, which is experimentally validated. This model is extended to predict the performance of a bidirectional on-off keyed (OOK) PON and experimentally verified. Three methods are investigated to improve the ONU modulator. First it is shown that transmitter pre-distortion can provide a doubling of the non-equalized datarate of a low modulation bandwidth ONU modulator. Next a four level intensity modulation format is demonstrated. It is shown that while this method is possible, it provides no improvement over OOK modulation. A novel method for modulating the orthogonal phases of an intensity modulated microwave subcarrier, similar to quadrature amplitude modulation (QAM), is demonstrated. Significant performance improvement is realized with this scheme. Finally the use of a VCSEL in PONs is evaluated. It is predicted that using a VCSEL as central office (CO) laser will offer minor benefits and some moderate challenges. Use of a vertical cavity semiconductor optical amplifier (VCSOA) as an ONU modulator is prevented by a dispersive nonlinearity. This nonlinearity leads to bistability. First demonstration of butterfly bistability in a 1550 nm VCSOA and record low power bistability are demonstrated.

Download or read book Semiconductor Optical Amplifiers written by Michael J. Connelly and published by Springer Science & Business Media. This book was released on 2007-05-08 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: The semiconductor optical amplifier has emerged as an important component in many optical fibre communication, switching and signal processing systems. This invaluable information source provides a comprehensive and detailed treatment of the design and applications of SOAs.

Download or read book Efficient Design of Wavelength Division Multiplexing WDM Based Optical Networks written by Byravamurthy Ramamurthy and published by . This book was released on 1998 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applications of Semiconductor Optical Amplifiers written by Kyriakos E. Zoiros and published by MDPI. This book was released on 2018-10-11 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Applications of Semiconductor Optical Amplifiers" that was published in Applied Sciences

Download or read book Design and Performance Analysis of WDM Optical Networks written by Ye Tao and published by . This book was released on 2006 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Wavelength Division Multiplexing (WDM) is now being widely used in optical networks. WDM significantly increases the capacity of a single fiber by allowing it to simultaneously transmit multiple wavelengths. While such enormous capacity is very exciting, it has also led to the advent of drastically more complex WDM networks. In this work, we consider two architecture design problems for optical networks: (1) the optimal amplifier placement problem, and (2) the traffic grooming, routing, and protection problem for optical networks. In an optical network, optical signals from transmitters attenuate gradually as they propagate through optical fibers, therefore their strength needs to be restored by optical amplifiers before they become too weak to be detected by receivers. Optical amplifiers, however, also introduce the spontaneous emission noise, which is a major problem associated with them. In general, a long optical channel needs enough amplifiers in order to limit the cumulative spontaneous emission noise and attain adequate amplification gain. In our amplifier placement problem, the goal is to minimize the cost associated with optical amplifiers in an optical network subject to constraints on the cumulative spontaneous emission noise. The optical network can be a linear or a mesh network, and the locations of amplifiers can be arbitrary or pre-specified, which are referred as continuous and discrete case, respectively. We propose several different methods based on various optimization techniques and heuristics to solve the problem. In the second part of this work, we consider the traffic grooming, routing, and protection problem in optical networks. There are two basic architectures used in optical networks: ring and mesh. The ring architecture is relatively simple and easy to implement, and it also provides a straightforward way for traffic protection. On the other hand, the mesh architecture is more resilient to various network failures, but is much more complex. Recently, a hybrid architecture that is based on and takes advantage of both ring and mesh architectures has been proposed. We study the traffic grooming, routing, and protection problem for ring, mesh, and hybrid architectures, and use a two-step approach in conjunction with the linear programming technique to solve the problem. Numerical results are provided for a comprehensive comparison between these different architectures.

Download or read book Long Reach RSOA Based Passive Optical Networks written by Sourav Mondal and published by LAP Lambert Academic Publishing. This book was released on 2014-10-01 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present access services like video on demand, live streaming, online gaming etc. require enormous amount of bandwidth and traditional digital subscriber line technology fails to meet up this requirement. The next generation networks, in particular, hybrid WDM-TDM Long-Reach Passive Optical Networks provide the required bandwidth and reduce the operational expenditure. Laser sources used at the Optical Network Units increase the cost due the extra equipment required for stabilizing the operating wavelength. To overcome this, a centralized source is installed at the Optical Line Terminal and the signal is reflected and intensity-modulated at the ONU, by using a special optical device Reflective Semiconductor Amplifier (RSOA), thus making the end receiver unit "colourless." The analytical model for RSOA has been described in detailed in this book. The primary objective of this enitre work is to examine the feasibility of hybrid WDM-TDM LR-PON physical layer uplink setup consisting of reflective ONUs with due consideration to the BER performance in presence of realistic and non-ideal characteristics of optical and optoelectronic devices used in the setup.

Download or read book Semiconductor Optical Amplifier Modeling Analysis and Simulation written by Manisha V. Mayavanshi and published by LAP Lambert Academic Publishing. This book was released on 2015-02-04 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mathematical model are required to aid in design of Semiconductor Optical Amplifier (SOA) and to predict their operational characteristics. SOAs is used to amplify signals at different wavelengths need a wideband SOA model. SOA models require accurate values for parameters such as material loss and recombination coefficients need parameter extraction using model predictions and experimental results. Mathematical model for Polarization dependent gain, noise, second and third order harmonic distortion, four waves mixing are simulated. This work is useful to the researchers who are working in research and development of optical network and Fiber Optic Communication Engineering.

Download or read book Semiconductor Optical Amplifiers for Ultra wideband Optical Systems written by Alexis Carbó Meseguer and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last few decades the world has undergone a major revolution that has deeply affected the way we use communication networks. New services and applications have appeared demanding a constant increase of the channel capacity. In this period, optical systems have been upgraded at pair with advanced signal processing techniques which have permitted the increase of the spectral efficiency approaching the system capacity to the fundamental limit. It is because is becoming extremely challenging to keep growing the system capacity by this means. In this work, an orthogonal direction is studied to further increase the fibre capacity: extending the optical bandwidth. With this purpose, the use of semiconductor optical amplifiers (SOA) is investigated to be implemented in future ultra-wideband (UWB) systems. The use of SOA amplification changes completely the paradigm in the design of an optical system since all the impairments added by the SOA must be considered. In this work, we assess the reservoir model, a simple yet powerful model, to analyze numerically the nonlinear regime of the SOA for WDM systems. We also show for the first that the linewidth enhancement factor of an SOA can be estimated with a coherent receiver. Finally, it is also studied how the correlation between channels degrades significantly the performance of the SOA and the inclusion of a decorrelation fibre is investigated. The conception of a UWB system is then studied. We characterize a novel ultra-wideband SOA developed by the French project CALIPSO which presents high gain in a 100-nm optical bandwidth with high output saturation power and 6-8 dB of noise figure. We analyze its nonlinear regime for WDM systems and we show for QPSK and 16 QAM modulation formats that the input saturation power can be overtaken by serveral dBs without important nonlinear penalty. On the other hand, a novel technique is studied to compensate fibre nonlinearities in UWB systems: the multicarrier multiplexing, which tries to exploit the concept of symbol rate optimization. Finally, we assess the capabilities of this novel UWB SOA for data-centre interconnection applications with two experiments transmitting up to 113 Tbps data troughput in a 100-nm continuous bandwidth link over 100 km of fibre and then testings is stability with real-time line cards between two points of presence (POP)of Facebook deployed in the Paris area.

Download or read book Semiconductor Optical Amplifiers to Extend the Reach of Passive Optical Networks written by Jenny McGeough and published by . This book was released on 2012 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis reports on Semiconductor Optical Amplifiers (SOAs) and their use in optical communication systems; in particular improving the reach of Passive Optical Networks (PON). Following a comprehensive overview of the components of optical communication systems a PON is introduced and the standard of Gigabit-PON (GPON) explained. The concept of extending the reach of GPON through the introduction of amplification is presented and the business drivers of the telecommunication operators detailed. The physics of SOAs are described followed by the parameters used to characterise them. Carrier dynamics of SOAs are explained and the methods of measurement of the carrier dynamics are detailed including the spectrogram technique. This method simultaneously measures the gain and phase recovery which is desirable for applications in long range telecommunications which require unchirped signals with a fast response for both gain and phase. Parameters of commercially available SOAs are compared with the requirements to extend the reach of PONs. Following this the fabrication tolerances for SOAs insensitive to polarisation dependent gain (PDG) are modelled. Results from SOA modelling showed that the greatest contributing factor to PDG variation was the active region thickness error. In the context of bulk production this requires a realistic tolerance of ~10nm to maintain PDG of ~1dB. A polarisation insensitive high gain SOA is designed and experimentally measured. This SOA is measured in the context of GPON and shown to extend the reach of the current standard by a record margin of 28dB. The limitation of the improvement is attributed to gain modulation sourced intersymbol interference (the patterning effect). The patterning effect has been reported in literature to be reduced through the introduction of SOAs with an active region made from quantum dot (Qdot) material. A comparative study of the gain and phase recovery time and alpha factor of various dimensional SOAs is presented. Using the spectrogram method it is shown that reducing the power and increasing the bias of the SOA can reduce the carrier recovery time. A Qdot active region SOAs is shown to considerably reduce the gain recovery time compared to a bulk SOA of similar length. The active region of the Qdot SOA alludes to a faster carrier recovery time which could be beneficial to extend the reach of PONs without patterning. However as these are more difficult to fabricate in mass production it is unknown if they are a viable solution on a commercial scale. In the context of GPON a low alpha factor is desired for minimizing chirp and phase nonlinearities during amplification of short pulses. An alpha factor study is presented and the Qdot SOA was measured to have the lowest alpha factor which could be beneficial for reducing chirp in 10G-PON.

Download or read book Optically Amplified Scalable WDM Networks Using Acousto Optic Filters for Amplification Gain Equalization and Signal Routing written by David A. Smith and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This final report discusses development of Acousto Optic Tunable Filter (AOTF) technology for wavelength division multiplexing (WDM) in optical networks. The ability of tho AOTF to function as a digital or analog wavelength selective filter. with independent control of each wavelength channel or spectral window allows the AOTF to solve the seemingly unrelated problems of gain equalization and wavelength channel routing simultaneously. An AOTF with intrinsic gain als provides the capability for a lossless switch. Specific results of the effort include: packaged sidelobe suppressed AOTF's as hybrid polarization independent switches for gain equalization experiments requirements for passive and active filters for effective gain equalization in single and cascaded Erbium Doped Fiber Optic Amplifiers. single amplifier cascades delivery of a gain equalizer subsystem to ONTC, the development of a mathematical model for AOTFs with gain fabrication of waveguides in Er:Ti:LiNbO3, requirements for optimum pump and device packaging of AOTFs with gain. demonstration of the gain and noise properties of AOTFs with gain and determination of optimal system performance of an AOTF with gain.

Download or read book Optically amplified Scalable WDM Networks Using Acousto optic Filters for Amplification Gain Equalization and Signal Routing written by David A. Smith and published by . This book was released on 1997 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: