Search results for "linéaire"
showing 10 items of 78 documents
Impact du profil de phase initial sur l'évolution asymptotique d'impulsions dans un amplificateur à fibre
2009
National audience; Nous étudions numériquement l'impact d'une dérive de fréquence initiale ou d'un saut de phase initial sur la dynamique asymptotique d'une impulsion se propageant dans un amplificateur à fibre à dispersion normale. Nous montrons notamment que si l'enveloppe de l'impulsion reste correctement décrite par l'expression analytique d'un similariton parabolique, des structures sombres peuvent néanmoins se superposer à cette enveloppe.
Dispositif à base de fibre optique non-linéaire pour la mise en évidence de gigue d'amplitude ou d'erreurs
2010
National audience; Nous proposons un dispositif permettant la mesure optique de faibles gigues d'amplitude en augmentant les fluctuations du signal d'un ordre de grandeur. Suivant la puissance de fonctionnement utilisée dans ce montage exploitant la non-linéarité d'une fibre optique, il est également possible de mettre en évidence de potentielles erreurs dans un signal.
AMPLIFICATION ET CONTROLE TOUT-OPTIQUE DE LA POLARISATION D'UN SIGNAL TELECOM CADENCE A 10 GB/S AU SEIN D'UNE FIBRE OPTIQUE
2012
National audience; Nous démontrons la possibilité de combiner l'amplification Raman et l'attraction de polarisation d'un signal retour-à-zéro cadencé à 10 Gb/s au moyen d'une onde pompe laser contra-propagative dans un unique segment de fibre
Cross-phase modulation effects in normal dispersive fibers and their applications
2018
In this Ph.D., physical effects arising from cross-phase modulation between twoorthogonally polarized signals propagating in normal dispersion fibers arestudied and some of their applications investigated.First, a 40-GHz pulse generator is designed by sending two orthogonallypolarized out-of-phase sinusoidal waves in a normally dispersive optical fiber.A large power imbalance between the two waves induces a periodic phasepotential for the weak replica which turns the normal dispersive defocusingregime into a focusing dynamics, thus compressing the sinusoidal wave intoshort and well-separated pulses.A signal sampler and magnifier was then designed using the same principle,sending a high powe…
Étude et manipulation de modes résonants en champ proche optique
2010
Within the quick nano-fabrication techniques evolution and the increasing needs in low space and energy opto-electronic functions on-chip integration, studies and control of electromagnetic resonances of sub-micrometric objects are crucial issues. One aim of this work was then to improve our knowledge of the light-matter interaction. To this end, optical near-field experiments and complementary numerical development of models have been performed to study electromagnetic resonances due to light-matter interaction in sub-micrometric resonators. As an introduction, the first part of the manuscript presents the main phenomena involved in near-field optical microscopy and the used SNOM operation…
Différents régimes impulsionnels dans un laser Raman à fibre optique
2008
National audience; Nous rapportons différents régimes impulsionnels observés au sein d'une cavité laser Raman en anneau.
Chalcogenide microstructured optical fibers : from linear to nonlinear properties
2010
International audience; In this talk, we review the linear properties of chalcogenide microstructured optical fibers (MOFs) of several types. We mainly focus our talk on mid-infrared applications of such fibers. We start with the general properties of solid core MOFs made of these high index glasses and compare them with the ones of silica. Then, we give some details concerning a solid core MOF made of TAS glass. Next, we describe the first guiding suspended chalcogenide MOF and explain how it was designed for supercontinuum generation in the mid-infrared. Both linear and nonlinear properties of As2S3 suspended core MOFs are also numerically studied. In the next part, We describe the design…
Ultra-high repetition all optical picosecond pulsed sources : applications in optical telecommunications
2013
This thesis presents the work carried out on the realization of fibered 40-GHz picosecond optical pulse sources in the telecommunications C-band. In the first part, we present a numerical and experimental study of the generation of 40-GHz pulse trains thanks to the nonlinear compression of an initial beat-signal by multiple Four-Wave Mixing process. Enhanced temporal stability is achieved by generating the sinusoidal beating thanks to a Mach-Zehnder modulator driven at its zero-transmission working point. In order to improve the quality of the generated pulses, we also demonstrate the suppression of stimulated Brillouin back-scattering by inserting several optical isolators into the compres…
Complex rogue wave in the fiber optics
2016
This manuscript presents the generation of complex rogue waves related to nonlinear instabilities occurring through the propagation of light in standard optical fibers. Linear and nonlinear physical phenomena involved are first listed, in particular some of them by analogy with the field of hydrodynamics. The different forms of rogue waves induced by the modulation instability process are then presented. They are also known as "breathers", and they are obtained by solving the nonlinear Schrödinger equation. From these exact solutions, various experimental systems were designed by means of numerical simulations based on two rogue-wave excitation methods. The first one is an exact generation …
High bit rate optical pulses sources generation and microstructured chalcogenide fibers characterizations
2011
This memory of thesis s' registered voter in the context of the FUTUR project financed by l' ANR and concerning the development of optical functions for the high bit-rate transmissions in the Network heart and carries on very high rates optical fibers sources generation and the optical chalcogenide microstructured fiber characterization. For this purpose, we study the linear and non-linear characteristics of microstructured chalcogenide fibers conceived and realized in various collaborations within the framework of the ANR FUTUR project. For that a great number of characterizations methods were developed giving a comparison between a standard single mode fiber and these microstructured chal…