Semiconductor optical amplifiers for ultra-wideband optical systems

• Main Author: Carbó Meseguer, Alexis
• Other Authors: Evry, Institut national des télécommunications
• Language: en
• Published: 2018
• Subjects: Système de transmission optique; Communications cohérentes; Amplification optique; Systèmes à très large bande; Amplificateur optique à semi-conducteurs; Optical transmission system; Coherent communications; Optical amplification; Ultra wideband systems; Semiconductor optical amplifier
• Online Access: http://www.theses.fr/2018TELE0010/document

Au cours des dernières décennies, le monde a subi une révolution majeure qui a profondément affecté comment on utilise les réseaux de communication. De nouveaux services et applications ont été apparus, tels que les réseaux sociaux, les jeux en ligne ou le streaming en direct, qui exigent une augmentation constante de la capacité des systèmes optiques. La motivation de ce travail est donc d'étudier la mise en œuvre d'un nouvel amplificateur SOA à très large bande avec une bande passante de plus de 100 nm afin d’étendre la capacité du système. L'utilisation de l'amplification SOA change complètement le paradigme dans la conception d'un système optique puisque toutes les dégradations ajoutées par la SOA doivent être considérées. Ainsi, la recherche d'un modèle analytique ou numérique capable de caractériser la nature non linéaire de ce dispositif est d'abord étudiée. Ensuite, on montre comment un SOA bien conçu peut non seulement amplifier un signal à large bande, mais également surmonter certains des principaux inconvénients du SOA devant EDFA. Finalement, on évalue la capacité de ce nouveau UWB SOA pour les applications d'interconnexion de centres de données avec deux expériences en transmettant jusqu'à 115 Tbps de données dans une liaison à bande passante continue de 100 nm sur 100 km de fibre et en testant la stabilité du système avec cartes de ligne en temps réelle entre deux points de présence (POP) de Facebook déployés dans la région parisienne === 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