{"id":1280,"date":"2020-05-07T11:16:00","date_gmt":"2020-05-07T09:16:00","guid":{"rendered":"https:\/\/samovar2022.int-evry.fr\/index.php\/2020\/05\/07\/des-solutions-a-de-nouveaux-defis-dans-les-reseaux-optiques-modernes-avec-perte-dependant-de-la-polarisation\/"},"modified":"2020-09-04T18:45:17","modified_gmt":"2020-09-04T16:45:17","slug":"des-solutions-a-de-nouveaux-defis-dans-les-reseaux-optiques-modernes-avec-perte-dependant-de-la-polarisation","status":"publish","type":"post","link":"https:\/\/samovar.telecom-sudparis.eu\/index.php\/2020\/05\/07\/des-solutions-a-de-nouveaux-defis-dans-les-reseaux-optiques-modernes-avec-perte-dependant-de-la-polarisation\/","title":{"rendered":"Des solutions \u00e0 de nouveaux d\u00e9fis dans les r\u00e9seaux optiques modernes avec perte d\u00e9pendant de la polarisation"},"content":{"rendered":"

L’Ecole doctorale : Ecole Doctorale de l’Institut Polytechnique de Paris
\net le Laboratoire de recherche SAMOVAR
\npr\u00e9sentent l\u2019AVIS DE SOUTENANCE de Monsieur Arnaud DUMENIL
\n<\/strong><\/p>\n

Autoris\u00e9 \u00e0 pr\u00e9senter ses travaux en vue de l\u2019obtention du Doctorat de l’Institut Polytechnique de Paris, pr\u00e9par\u00e9 \u00e0 T\u00e9l\u00e9com SudParis en :
\nElectronique et Opto\u00e9lectronique
\n\u00ab Des solutions \u00e0 de nouveaux d\u00e9fis dans les r\u00e9seaux optiques modernes avec perte d\u00e9pendant de la polarisation \u00bb<\/p>\n

le vendredi 15 mai 2020 \u00e0 14h00<\/p>\n

SOUTENANCE EN WEBCONFERENCE<\/p>\n

Dispositions exceptionnelles durant la crise sanitaire li\u00e9e au Covid19 : ordonnance n\u00b0 2020-351 du 27 mars 2020 – Arr\u00eat\u00e9 du 21 avril 2020 –<\/p>\n

NOR : ESRS2009945A<\/p>\n


\nMembres du jury :<\/strong><\/p>\n

M. Badr-Eddine BENKELFAT , Professeur, T\u00e9l\u00e9com SudParis, FRANCE – Directeur de th\u00e8se
\nM. Magnus KARLSSON, Professeur, Chalmers University of Technology, SU\u00c8DE – Rapporteur
\nM. Darko ZIBAR, Associate Professor, Technical University of Denmark, DANEMARK – Rapporteur
\nMme Iryna ANDRIANOVA , Professeure, ENSEA, FRANCE – Examinatrice
\nMme Ghaya REKAYA-BEN OTHMAN, Professeure, T\u00e9l\u00e9com Paris, FRANCE – Examinatrice
\nM. Elie AWWAD, Ma\u00eetre de Conf\u00e9rences, T\u00e9l\u00e9com Paris, FRANCE – Encadrant de th\u00e8se<\/p>\n

R\u00e9sum\u00e9 :<\/strong><\/p>\n

La demande de d\u00e9bit en augmentation constante requiert des canaux de communication fiables et robustes. Les r\u00e9seaux optiques terrestres ainsi que les liens sous-marins repr\u00e9sentent le c\u0153ur de l’infrastructure des t\u00e9l\u00e9communications au niveau mondial, et transportent des centaines de canaux fr\u00e9quentiels modul\u00e9s \u00e0 haut d\u00e9bit. Ces liens se composent non seulement de kilom\u00e8tres de fibre mais aussi de composants optiques comme les amplificateurs \u00e0 fibre dop\u00e9e \u00e0 l’erbium (EDFA) pour relever r\u00e9guli\u00e8rement la puissance des signaux att\u00e9nu\u00e9s, ou encore des commutateurs s\u00e9lectifs en longueur d’onde (WSS) qui routent le signal vers leur destination. Dans cette th\u00e8se, nous nous int\u00e9ressons \u00e0 une p\u00e9nalit\u00e9 sp\u00e9cifique qui survient dans ces syst\u00e8mes et qui r\u00e9duit le d\u00e9bit d’information dans une propagation optique. Les composants optiques discrets pr\u00e9sentent typiquement une anisotropie en polarisation : un d\u00e9s\u00e9quilibre de perte (ou gain) appara\u00eet entre les deux polarisations d’un signal optique multiplex\u00e9 en polarisation. Cet effet non unitaire appel\u00e9 pertes d\u00e9pendant de la polarisation (abr\u00e9g\u00e9 PDL en anglais) d\u00e9grade la qualit\u00e9 de transmission dans les syst\u00e8mes optiques actuels et futurs. Dans le cadre des transmissions multiplex\u00e9s en polarisation, nous caract\u00e9risons la perte de capacit\u00e9 induite par la PDL. Pour commencer, des mod\u00e8les de canal sont attentivement \u00e9tudi\u00e9s et deux approches sont pr\u00e9sent\u00e9es : un canal avec des \u00e9l\u00e9ments PDL distribu\u00e9s avec un bruit \u00e9galement distribu\u00e9, ou alors un canal \u00e9quivalent simplifi\u00e9 en un seul \u00e9l\u00e9ment. Nous analysons les limites fondamentales de communication associ\u00e9es \u00e0 ces mod\u00e8les. Nous montrons en outre que la capacit\u00e9 d’un canal PDL d\u00e9pend en pratique de l’orientation de l’\u00e9tat de polarisation du signal incident. Nous passons ensuite en revue l’\u00e9tat de l’art de sch\u00e9mas de modulation att\u00e9nuant l’effet de PDL puis nous proposons deux nouveaux sch\u00e9mas de modulation multi-dimensionnels qui augmentent la performance minimum et moyenne du canal. Ces deux modulations sont des transformations unitaires de symboles M-QAM qui n’utilisent pas de degr\u00e9s de libert\u00e9 autres que les quatre d\u00e9j\u00e0 utilis\u00e9s pour chaque longueur d’onde (encodage en phase et quadrature de phase sur les deux \u00e9tats de polarisation). Nous proposons succinctement une extension de ces premiers r\u00e9sultats \u00e0 des communications optiques plus g\u00e9n\u00e9ralement multiplex\u00e9s en dimension spatiale et impact\u00e9es par des pertes d\u00e9pendantes de mode, qui pr\u00e9sentent un d\u00e9s\u00e9quilibre de gain identique. Au-del\u00e0 de la construction de modulations au niveau du transmetteur, nous \u00e9tudions la perte de performance en pr\u00e9sence de PDL d’une cha\u00eene de traitement de signal conventionnelle et s\u00e9quentielle par comparaison avec une \u00e9galisation et d\u00e9codage joint. Cette perte additionnelle de capacit\u00e9 r\u00e9sultant du traitement s\u00e9quentiel non optimal est \u00e9valu\u00e9e pour diff\u00e9rents formats de modulations ainsi que diff\u00e9rents points de fonctionnement. Enfin, nous exposons une validation exp\u00e9rimentale des deux sch\u00e9mas de modulation propos\u00e9s, aussi bien sur un \u00e9l\u00e9ment de PDL seul ou sur un canal PDL distribu\u00e9, et montrons comme attendu une robustesse augment\u00e9e vis-\u00e0-vis de la PDL.<\/p>\n

Abstract :<\/strong><\/p>\n

Large amounts of ever-increasing global data traffic require sound and reliable communication channels. Optical terrestrial networks and submarine links are at the very heart of the global telecom infrastructure, and carry hundreds of frequency channels modulated at very high rates. These links include not only kilometers of fiber but also optical elements such as Erbium-Doped Fiber-Amplifiers (EDFA) to amplify periodically the attenuated signals and Wavelength Selective Switches (WSS) to route the signals to their assigned destinations. In this thesis, we explore a specific rate-degrading impairment of the optical propagation that raises in those systems. Discrete optical elements often exhibit a polarization anisotropy that emerges as a gain or loss imbalance between the two polarization tributaries of the polarization-multiplexed optical signals. This non-unitary effect called Polarization Dependent Loss (PDL) impairs the quality of transmission in current and next-generation optical systems. In the context of polarization-multiplexed signals, we assess the capacity loss induced by PDL. First, channel models are carefully studied and two approaches are described: a channel with distributed PDL elements and distributed noise or a simplified single-element equivalent channel. Making use of these models, we then analyze their fundamental limits of communications. We show that the PDL channel capacity depends in practice on the state-of-polarization orientation of the incident signal. We then review the state-of-the art of PDL-mitigating modulation schemes and propose two new multi-dimensional signaling schemes that enhance worst-case and average performance. These two modulations are unitary transforms of M-QAM symbols and do not make use of additional degrees of freedom apart from the four already-used dimensions per wavelength (in-phase and quadrature channels of two polarization states). We briefly extend these first results to space-division-multiplexed optical communications impaired by mode dependent loss (MDL) that present a similar gain imbalance. Beyond signal shaping at the transmitter side, we study the performance loss of a conventional, sequential signal processing chain at the receiver side in presence of PDL, in comparison with a joint equalization-decoding scheme. The additional capacity loss due to the mismatch sequential processing is evaluated for several modulation formats and at different operating points. Finally, we report an experimental validation of the two proposed signaling schemes, both on a single PDL element and on a distributed PDL channel, demonstrating the predicted enhanced robustness to PDL.<\/p>\n","protected":false},"excerpt":{"rendered":"

L’Ecole doctorale : Ecole Doctorale de l’Institut Polytechnique de Paris et le Laboratoire de recherche SAMOVAR pr\u00e9sentent l\u2019AVIS DE SOUTENANCE de Monsieur Arnaud DUMENIL Autoris\u00e9 \u00e0 pr\u00e9senter ses travaux en vue de l\u2019obtention du Doctorat de l’Institut Polytechnique de Paris, pr\u00e9par\u00e9 \u00e0 T\u00e9l\u00e9com SudParis en : Electronique et Opto\u00e9lectronique \u00ab Des solutions \u00e0 de nouveaux 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