Στις μέρες μας, οι αυξανόμενες απαιτήσεις για υπηρεσίες υψηλού φασματικού εύρους ζώνης επιβάλλουν την ανάπτυξη νέων τεχνολογιών στο σχεδιασμό των δικτύων νέας γενιάς, ικανές να προσφέρουν α) χαμηλό κόστος κατά το σχεδιασμό του συστήματος, β) μεγάλη απόσταση μετάδοσης, γ) πολλοί χρήστες και δ) υψηλό εύρος ζώνης στην πλευρά του χρήστη για την παροχή των νέων υπηρεσιών. Ωστόσο, τα οπτικά δίκτυα λόγω των αναλογικών χαρακτηριστικών των οπτικών σημάτων τους, υποφέρουν από γραμμικές και μη γραμμικές παραμορφώσεις. Αυτές οι παραμορφώσεις επηρεάζουν άμεσα την απόδοση των συστημάτων και η επίδραση τους αυξάνει με την αύξηση του ρυθμού μετάδοσης. Παραδοσιακά χρησιμοποιούνται οπτικοί τρόποι για την εξομάλυνση των παραμορφώσεων. Ωστόσο, η ραγδαία ανάπτυξη στον τομέα των ηλεκτρονικών αναδεικνύει την ηλεκτρονική εξομάλυνση των παραμορφώσεων ως μία ευέλικτη, χαμηλού κόστους ολοκληρωμένη και βιώσιμη λύση που αποφεύγει τις επιπρόσθετες οπτικές απώλειες. Σκοπός της διδακτορικής διατριβής είναι η εξομάλυνση με αποδοτικό τρόπο των πιο σημαντικών παραμορφώσεων (χρωματική διασπορά, αυτοδιαμόρφωση φάσης και φαινόμενο αλληλουχίας φίλτρων) που δημιουργούνται στα οπτικά δίκτυα και ειδικότερα στα μητροπολιτικά δίκτυα, στα δίκτυα πρόσβασης, και στα παθητικά δίκτυα. Από σχεδιαστικής πλευράς του συστήματος, αυτή η διατριβή προτείνει τη βέλτιστη χρησιμοποίηση λύσεων χαμηλού κόστους, ικανές να επεκτείνουν (σε ρυθμό μετάδοσης και απόσταση) την χρησιμοποίησή τους σε οπτικά δίκτυα νέας γενιάς. Πιο συγκεκριμένα, η απόδοση της ηλεκτρονικής αντιστάθμισης μελετάται για συστήματα που χρησιμοποιούν χαμηλού κόστους, συμβατικούς πομπούς laser άμεσης διαμόρφωσης (DML), που οδηγούνται στα 10 Gb/s. Σκοπός σε αυτήν την περίπτωση είναι η αύξηση της απόστασης και του ρυθμού μετάδοσης που μπορεί να επιτευχθεί, εξομαλύνοντας τις παραμορφώσεις που δημιουργούνται εξαιτίας των χαρακτηριστικών των πομπών και αυτών που δημιουργούνται κατά τη μετάδοση του σήματος (χρωματική διασπορά, αυτοδιαμόρφωση φάσης και φαινόμενο αλληλουχίας φίλτρων) με την βέλτιστη χρησιμοποίηση ηλεκτρονικού εξισωτή. Επιπλέον, όσον αφορά τα παθητικά δίκτυα πρόσβασης νέας γενιάς, μελετάται μία αποδοτική και χρήσιμη τεχνική, χρησιμοποιώντας τα πλεονεκτήματα της χρήσης του ηλεκτρονικού εξισωτή στην πλευρά του δέκτη (OLT). Η πειραματική μελέτη εστιάζει στα παθητικά οπτικά δίκτυα (PON) στα 10 Gb/s χρησιμοποιώντας χαμηλού κόστους, χαμηλού εύρους ζώνης RSOA στην πλευρά του χρήστη (ONU), και ηλεκτρονικό εξισωτή στην πλευρά του δέκτη (OLT). Αυτή η τεχνική προσφέρει την απαιτούμενη ευελιξία για την προσαρμογή στις καινούργιες συνθήκες του συστήματος και την υλοποίηση των απαιτήσεων (πολύ μεγάλες αποστάσεις μετάδοσης, αριθμό χρηστών και ρυθμό μετάδοσης), ενώ ταυτόχρονα μπορεί και εκπληρώνει τις απαιτήσεις χαμηλού κόστους στην ανάπτυξη των μελλοντικών δικτύων πρόσβασης νέας γενιάς. / Nowadays, the rapid increase in bandwidth demanding services imposes new technological directions in the design of next generation optical networks with the purpose to achieve: a) reduced cost, b) larger transmission distances, c) larger number of users and d) higher bandwidth connectivity to the end user. However, due to the analogue nature of the optical signals, the optical networks suffer from a variety of linear and non-linear impairments. These impairments have a direct impact in the signal’s bit error rate performance, while their effect increases as bit rate increases. The compensation of impairments has been traditionally performed by optical means. However, the rapid increase in available electronic processing power has made electronic mitigation of impairments a viable option, leading to an adaptive, low cost and integrated solution which avoids additional optical losses. The goal of this thesis is to study the effective mitigation by electronic means of the most important impairments (i.e. chromatic dispersion, self phase modulation and filter concatenation) that are related with optical networks and particularly metropolitan, access and passive optical networks. From the network (and system) design point of view, this study proposes the optimum use of certain low cost solutions able to extend (in bit rate and coverage) the applicability of next generation optical networks. More specifically, the effectiveness of electronic equalization is examined for systems utilizing low cost, conventional directly modulated laser (DML) sources that are operated at 10 Gb/s. The purpose in this case is to extend the reach and operating data rate of these systems by mitigating the transmission limiting effects due to the source characteristics and the link impairments (dispersion, self-phase modulation, and filter concatenation) with the optimum use of electronic equalization. Moreover, with respect to next generation optical access networks an effective and useful design approach on PON systems is fully investigated, by using the benefits of electronic equalization at the receiver side (ΟLT). This experimental system studies are focusing on PON systems operated at 10 Gb/s by using low cost and low bandwidth RSOAs at the ONU side assisted by electronic equalization at the receiver (ΟLT). This technique offers the required flexibility for the optimum adaptation on the specific network characteristics (in terms of covered distance, number of users and bit rate) and additionally meets the requirements for the development and further extension of future low cost optical access networks.

The main goal of this diploma thesis is to design of high-speed optical network. The first part deals with theoretical knowledge in the field of optical transmissions, especially principle of wavelength division multiplexing. Generally speaking, this part is dedicated to optical connections over long distances. It will concentrate on different types of wavelength division multiplexing, optical fiber amplifiers and other basic optical components. Then it discusses influence of negative effects acting on optical transmission and discusses how to reduce or suppress their influence. Subsequently, there is designed backbone network in the Czech Republic in OptiSystem 7.0 software and are verified some mentioned theoretical knowledge. One of chapters also presents results of measurements of real optical routes in our state. The second part of the diploma thesis moves its attention on that part of optical network, which provides data connectivity to end users, that means it is focused on optical access network. There are described the most common topologies, standards and components. Based on these findings, in the last chapter, there is worked out design of optical access network FTTH (more precisely FTTD) in the selected location. Afterwards, the design is transferred to the OptiSystem 7.0 software, where is verified its functionality.

O presente trabalho descreve o desenvolvimento e implementação de duas configurações distintas de um receptor optoeletrônico integrado. A primeira configuração é similar a um projeto encontrado na literatura mas apresenta diversas modificações que lhe conferiram melhor desempenho em comparação ao projeto original. A segunda configuração é uma nova proposta deste trabalho. O receptor foi desenvolvido e implementado visando sua aplicação em redes de comunicações ópticas passivas (PONs) de alta velocidade comutadas a pacote, para possibilitar a utilização da técnica de multiplexação em comprimento de onda (WDM), aumentando assim a capacidade de transmissão da rede, em particular no ramo de ligação da rede de serviços com o usuário final, denominado rede de acesso. O principal objetivo do receptor aqui desenvolvido foi proporcionar uma sintonia rápida entre os canais disponíveis na rede, possibilitando sua seleção num tempo inferior àquele necessário para a transmissão de um único pacote de informação, diminuindo assim o atraso de sintonia e, por conseguinte, a perda de informação. Para tanto, os circuitos integrados implementados e caracterizados referem-se aos circuitos de chaveamento eletrônico e do amplificador de transimpedância das duas configurações investigadas. Os dados experimentais obtidos para as duas configurações confirmaram a previsão de chaveamento dos canais de entrada num intervalo de tempo da ordem de alguns nanosegundos, o que é totalmente compatível com a velocidade de transmissão das aplicações a que se destina este receptor (aproximadamente 5 Gbits/s). Adicionalmente, são apresentados os dados experimentais relativos à freqüência de corte, ganho direto, isolação, relação on/off e características de ruído dos circuitos implementados. / The present work describes the design and implementation of two configurations of an integrated optoelectronic receiver. The first one is similar to a previously reported design but with some modifications to improve its performance. The second one is a new proposal of this work. The goal of the receiver design and implementation was its application in high bit rate packet-switched passive optical networks (PONs) employing the wavelength division multiplexing (WDM) technique to increase the network capacity, in particular on the connection branch of the network core with the final user, the access network. The main goal of the receiver design was to achieve a fast channel tuning, allowing a tuning time smaller than the required for the transmission of a single information packet, decreasing the tuning latency and, therefore, the rate of information packet loss. In order to accomplish this goal, the implemented and tested integrated circuits include the electronic switching circuit and the transimpedance amplifier for both configurations investigated. The measured data for both configurations confirm the expected input channel switching time results, of about a few nanoseconds, which is certainly useful for the expected bit rate of operation (approximate 5 Gbps). Additionally, experimental results concerning cutoff frequency and bandwidth, direct gain, isolation, on/off ratio, and noise characteristics of both implemented circuits are presented.

Η παρούσα διδακτορική διατριβή πραγματεύεται την ανάλυση και προσομοίωση τηλεπικοινωνιακών δικτύων πολυδιάστατης κίνησης, ενώ δίνεται ιδιαίτερη έμφαση στα οπτικά δίκτυα. Βασικός σκοπός της διατριβής αποτελεί η ανάπτυξη αναλυτικών μοντέλων για τον υπολογισμό παραμέτρων απόδοσης του δικτύου, όπως η πιθανότητα απώλειας σύνδεσης, πιθανότητα απώλειας κλήσης, η καθυστέρηση μετάδοσης και το ποσοστό χρησιμοποίησης του καναλιού μετάδοσης. Τα προτεινόμενα αναλυτικά μοντέλα διαφοροποιούνται ανάλογα με την τεχνολογία δικτύου. Οι τεχνολογίες αυτές είναι: Α) Οπτικά δίκτυα δρομολόγησης μήκους κύματος. Β) Οπτικά δίκτυα πρόσβασης. Γ) Ασύρματα δίκτυα πρόσβασης στο Διαδίκτυο. Για οπτικά δίκτυα δρομολόγησης μήκους κύματος αρχικά μελετάται η περίπτωση απλής οπτικής ζεύξης, ενώ στη συνέχεια εξετάζεται δίκτυο πολλαπλών κόμβων τυχαίας τοπολογίας. Επίσης, προτείνονται αναλυτικά μοντέλα για την περίπτωση της μεταγωγής οπτικών πακέτων με την αποτίμηση της απόδοσης ενός οπτικού διακόπτη, αλλά και δικτύου μεταγωγής οπτικών πακέτων τυχαίας τοπολογίας. Ακολούθως, προτείνονται αναλυτικά μοντέλα για την αποτίμηση της απόδοσης παθητικών οπτικών δικτύων, τα οποία υλοποιούν διαφορετικές μεθόδους πολλαπλής πρόσβασης. Για την περίπτωση της πολλαπλής πρόσβασης με διαίρεση χρόνου μελετάται το παθητικό οπτικό δίκτυο Ethernet, το οποίο υποστηρίζει πολυδιάστατη κίνηση. Αναφορικά με την πολυπλεξία με διαίρεση μήκους κύματος μελετάται ένα υβριδικό παθητικό οπτικό δίκτυο σε επίπεδο κλήσεων. Οι κλήσεις διακρίνονται ανάλογα με τη διαδικασία άφιξης σε τυχαίες και ψευδοτυχαίες κλήσεις, ανάλογα με τις απαιτήσεις σε εύρος ζώνης σε κλήσεις με σταθερές και ελαστικές απαιτήσεις και ανάλογα με τη συμπεριφορά τους κατά την παραμονή τους στο δίκτυο σε κλήσεις σταθερού ρυθμού μετάδοσης και σε κλήσεις οι οποίες εναλλάσσονται μεταξύ ενεργών περιόδων μετάδοσης και περιόδων σιγής. Τέλος, προτείνονται αναλυτικά μοντέλα υπολογισμού απωλειών για την περίπτωση της πολλαπλής πρόσβασης με διαίρεση οπτικού κώδικα, τα οποία λαμβάνουν υπ’όψιν πολλαπλές υπηρεσίες, την παρουσία προσθετικού θορύβου, αλλά και τη δραστηριότητα του χρήστη. Για την αποτίμηση της απόδοσης ασύρματων δικτύων πρόσβασης στο Διαδίκτυο προτείνονται αναλυτικά μοντέλα, τα οποία υλοποιούν το πρωτόκολλο ΙΕΕΕ 802.11 ή το πρωτόκολλο ΙΕΕΕ 802.11e. Η προτεινόμενη ανάλυση υπολογίζει τόσο τη διεκπεραιωτική ικανότητα του δικτύου, όσο και τη συνολική καθυστέρηση μετάδοσης πακέτου ως συνάρτηση της καθυστέρησης στο ασύρματο μέσο και της καθυστέρησης στην ουρά αναμονής. Σε όλες τις περιπτώσεις η ακρίβεια των προτεινόμενων μοντέλων πιστοποιείται/ελέγχεται με την προσομοίωση του δικτύου στον υπολογιστή. / In this PhD dissertation multi-rate models are examined for the performance analysis of telecommunication networks through mathematical analysis and simulation. Particular emphasis is given to optical networks. The main goal is the development of analytical models for the calculation of network performance metrics, such as blocking probabilities, transmission delay and utilization of the common channel. The proposed analytical models are distinguished according to the network technologies. Three different technologies are considered: A) Wavelength routed optical networks. B) Optical access networks. C) Wireless Internet access networks. Multi-rate loss models are proposed for the performance evaluation of wavelength routed optical networks. Firstly, the case of a single link is considered and then a mesh all-optical network is examined. In addition, analytical models are proposed for Optical Packet Switching (OPS) networks, for the case of an all-optical OPS switch and of an OPS mesh network. Multi-rate analytical models are proposed for the evaluation of the performance of Passive Optical Networks (PONs) implementing different multiple access methods. For the case of Time Division Multiple Access (TDMA) the Ethernet PON is studied, which supports multiple service-classes. Regarding the Wavelength Division Multiplexing (WDM) PONs a hybrid WDM-TDMA PON is considered and the call-level performance is evaluated. Calls are distinguished by their arrival process, which can be random or quasi random, by their bandwidth requirements, which can be fixed of elastic and by their behavior during their service, which can be calls of fixed transmission rate or calls that alternate between ON and OFF periods. Finally multi-rate loss models are proposed for the case of Optical Code Division Multiple Access (OCDMA) PONs that take into account the user activity and the presence of additive noise in the transmission channel. For the performance analysis of wireless Internet access networks analytical models are proposed, which implement the IEEE 802.11 protocol or the IEEE 802.11e protocol. The proposed analysis calculated the saturation throughput and the end-to-end packet delay as a function of the Medium Access Control (MAC) delay and the queueing delay. In all cases the accuracy of the proposed models is validated through simulation.

[pt] Com a crescente demanda por maior capacidade na transmissão de dados, uma solução tem sido estudada para transmissão de rádio sobre fibra combinando múltiplos canais de dados sobre a portadora óptica na rede de acesso baseada em multiplexação por sub-portadoras. Ademais, essa rede de acesso é comumente ramificada na forma de uma rede óptica passiva. Monitoramento desses enlaces em fibra é, então, cada vez mais importante. A tecnologia atual de reflectometria óptica no domínio do tempo utilizada para monitoramento opera em um comprimento de onda óptico separado e possui ampla largura de banda de detecção, tornando-se relativamente cara. A busca por uma alternativa de monitoramento de alta precisão e baixo custo é de suma importância para a oferta de transmissão com garantia de qualidade de serviço. Neste trabalho, o uso de multiplexação por sub-portadoras é explorado, incorporando uma técnica de monitoramento de varredura de tom de baixa frequência na transmissão de dados. Um modelo matemático para a resposta em frequência do enlace foi derivado e a localização e a intensidade de uma falha são estimadas através da comparação com a amplitude e a fase detectadas da luz retroespalhadaa medida em que é feita uma varredura de frequência do sinal de monitoramento, aplicando-se um algoritmo de minimos quadrados. O modelo proposto considera que a medida do enlace antes da ocorrência de uma falha é conhecida. Uma única falha nova pode então ser detectada com precisão e sua posição e intensidade são estimadas da maneira descrita. / [en] With ever growing demand for higher capacity in data transmission, a solution has been proposed for analog Radio over Fiber transmission, combining several data channels over the optical carrier in the access network using Sub-Carrier Multiplexing (SCM). Furthermore, this access network is often branched in the form of a passive optical network (PON). Monitoring such fiber links is thus increasingly important. Current optical time domain reflectometry (OTDR) technology used for monitoring operates at a separate optical wavelength and has wide bandwidth detection, making it relatively costly. The pursuit of a low cost, high precision monitoring alternative is of paramount importance for cost effective quality of service (QoS) improvement. In this work employment of SCM for data multiplexing is exploited embedding a low frequency tone sweep monitoring technique into data transmission. A mathematical model for the frequency response of the link was derived and the fault location and intensity is estimated through comparison with acquired amplitude and phase of the backscattered light for the varying frequency by applying a simple least mean squared (LMS) algorithm. The modeling suggested requires that measurement of the link prior to the occurrence of a fault is known. A single new fault can then be accurately detected and its position and intensity estimated in the way described.

O presente trabalho descreve o desenvolvimento e implementação de duas configurações distintas de um receptor optoeletrônico integrado. A primeira configuração é similar a um projeto encontrado na literatura mas apresenta diversas modificações que lhe conferiram melhor desempenho em comparação ao projeto original. A segunda configuração é uma nova proposta deste trabalho. O receptor foi desenvolvido e implementado visando sua aplicação em redes de comunicações ópticas passivas (PONs) de alta velocidade comutadas a pacote, para possibilitar a utilização da técnica de multiplexação em comprimento de onda (WDM), aumentando assim a capacidade de transmissão da rede, em particular no ramo de ligação da rede de serviços com o usuário final, denominado rede de acesso. O principal objetivo do receptor aqui desenvolvido foi proporcionar uma sintonia rápida entre os canais disponíveis na rede, possibilitando sua seleção num tempo inferior àquele necessário para a transmissão de um único pacote de informação, diminuindo assim o atraso de sintonia e, por conseguinte, a perda de informação. Para tanto, os circuitos integrados implementados e caracterizados referem-se aos circuitos de chaveamento eletrônico e do amplificador de transimpedância das duas configurações investigadas. Os dados experimentais obtidos para as duas configurações confirmaram a previsão de chaveamento dos canais de entrada num intervalo de tempo da ordem de alguns nanosegundos, o que é totalmente compatível com a velocidade de transmissão das aplicações a que se destina este receptor (aproximadamente 5 Gbits/s). Adicionalmente, são apresentados os dados experimentais relativos à freqüência de corte, ganho direto, isolação, relação on/off e características de ruído dos circuitos implementados. / The present work describes the design and implementation of two configurations of an integrated optoelectronic receiver. The first one is similar to a previously reported design but with some modifications to improve its performance. The second one is a new proposal of this work. The goal of the receiver design and implementation was its application in high bit rate packet-switched passive optical networks (PONs) employing the wavelength division multiplexing (WDM) technique to increase the network capacity, in particular on the connection branch of the network core with the final user, the access network. The main goal of the receiver design was to achieve a fast channel tuning, allowing a tuning time smaller than the required for the transmission of a single information packet, decreasing the tuning latency and, therefore, the rate of information packet loss. In order to accomplish this goal, the implemented and tested integrated circuits include the electronic switching circuit and the transimpedance amplifier for both configurations investigated. The measured data for both configurations confirm the expected input channel switching time results, of about a few nanoseconds, which is certainly useful for the expected bit rate of operation (approximate 5 Gbps). Additionally, experimental results concerning cutoff frequency and bandwidth, direct gain, isolation, on/off ratio, and noise characteristics of both implemented circuits are presented.

[pt] Para suportar os requisitos das redes móveis de 5a geração (5G), os sistemas de comunicação óptica serão usados nas redes de acesso. Isso ocorre porque a evolução das RAN (Radio Access Networks) incluem a centralização do equipamento mais crítico para implantar pontos de acesso móveis de baixa potência, como DAS (Distributed Antenna Systems) e Small Cells. Os serviços emergentes solicitam a implantação de tecnologias de rádio sobre fibra com ênfase na eficiência de largura de banda, eficiência energética e alta confiabilidade. Neste âmbito, um monitoramento eficiente da camada física é imperativo para a operação dessas redes. O sistema de monitoramento deve fornecer uma localização de falhas em serviço, econômico, centralizado e com impacto mínimo para a transmissão de dados. Esta tese propõe vários sistemas de monitoramento incorporado no transceptor utilizando reflectometria óptica no domínio do tempo. Os sistemas de monitoramento são testados em diferentes sistemas de transmissão de dados e arquiteturas de rede, onde é apresentada uma validação simulada e outras experimentais. / [en] In order to support the requirements for 5th generation mobile networks (5G), optical communication systems will be used in the access part of the network. This is because the evolution of radio access networks includes the centralization of the most critical equipment in order to deploy low power mobile access points, like distributed antenna systems and small cells. The emerging services call for the deployment of radio over fibre technologies with emphasis on bandwidth efficiency, energy efficiency and high reliability. Within this scope, an efficient monitoring of the physical layer would become essential for the operation of these networks. The monitoring system should provide in-service, cost efficient and centralized fault localization with minimum impact on data transmission. This thesis proposes several transceiver-embedded optical time domain reflectometry monitoring systems. The monitoring systems are tested over different data transmission systems and network architectures, where one architecture was simulated and several others experimentally validated.

Initialement poussées par le marché résidentiel, les évolutions du réseau d’accès optique sont aujourd’hui également stimulées par l’expansion du réseau mobile. Comme le montre le premier chapitre de ce document, l’introduction d’un multiplexage en longueur d’onde dense constitue l’une des solutions privilégiées pour permettre la montée en débit dans les réseaux d’accès optique. Dans cette thèse, l’impact de l’introduction du multiplexage en longueur d’onde dense est étudié sous trois axes :• Une prochaine étape de l’évolution des technologies pour les réseaux d’accès passerait par une hybridation entre d’une part, un multiplexage temporel (hérité des précédentes générations), et d’autre part, un multiplexage en longueur d’onde dense. Cette technologie, appelée NGPON2-TWDM, permet aujourd’hui d’envisager des débits de 40Gb/s à 80Gb/s grâce à 4 ou 8 canaux. Les difficultés liées à la stabilité de la longueur d’onde lors de l’émission de données en mode paquet dans le sens montant du lien, ainsi que les solutions associées, sont étudiées dans le second chapitre.• L’importance du marché que représente le réseau d’accès optique (aussi bien pour les clients résidentiels que pour les réseaux mobiles), induit la nécessité pour les différentes générations de technologies de coexister au sein d’une même infrastructure. Du fait des fortes puissances optiques en jeu et des plages spectrales allouées à chaque technologie, cette coexistence peut induire des interactions entre technologies par émission Raman stimulée, dont le principe et les impacts sont décrits dans le troisième chapitre.• Enfin, la quatrième partie de ce document est dédiée à l’étude des limites et potentialités de la technologie self-seeded pour le multiplexage en longueur d’onde dense en bande O, capable de stabiliser automatiquement et passivement la longueur d’onde d’émission de chacun des émetteurs du système. / Initially led by the residential market, today’s optical access network evolutions are stimulated by mobile network expansion. As shown in the first chapter of this document, dense wavelength division multiplexing is one of the favorite solutions in order to increase optical access networks throughput. In this thesis, we propose a study of dense wavelength division multiplexing introduction according to three main topics :• Service providers and equipment suppliers have decided that the next step in residential market evolution will consist in a hybridization between, on one hand, a legacy time division multiplexing, and on the other hand, a dense wavelength division multiplexing. Named NG-PON2, this technology allows today 40Gb/s to 80Gb/s thanks to 4 to 8 channel pairs. Wavelength stability of the upstream emitter under burst mode operation, and related solutions, are studied in the second chapter.• Market importance (for both residential market and mobile networks) requires the different technologies generations to coexist on the same infrastructure. Due to the high optical power and the wavelength spans allocated to each technology, this coexistence can lead to technologies interactions by stimulated Raman scattering, as described in the third chapter.• Finally, the fourth part of this document describes the limits and potentialities of the self-seeded emitter technology for O-band dense wavelength division multiplexing, able to automatically and passively self-stabilize the wavelength of each emitter.