Search results for "Optique non-Linéaire"
showing 7 items of 17 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.
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 …
Caractérisation d'une fibre optique ultra non-linéaire en verre de chalcogénure
2009
session orale 3 « Effets nonlinéaires » [Ma1.4], http://optiquelille2009.univ-lille1.fr/; National audience; Nous présentons les résultats expérimentaux concernant la caractérisation d'une fibre optique microstructurée en verre de chalcogénure de composition AsSe. Ces mesures concernent l'atténuation, la dispersion, l'aire effective et le coefficient non-linéaire du troisième ordre. Cette fibre présente un fort potentiel pour des applications non-linéaires avec un coefficient non-linéaire Kerr de 15 400 W-1m-1.
Fiber-based light source for biomedical applications
2013
This manuscript presents the work done concerning the development of a light source used for biomedical imaging and more particularly for coherent Raman scattering imaging. In fact an efficient broadcasting of these ones is hampered by the need of two synchronized and wavelength shifted pulses. As so, the handiness and frequency conversion capabilities of nonlinear fiber optics are used to circumvent this technological lock. First of all, an easy wavelength tunable source is set by the use of the self-shifting in optical frequency of a soliton. A study of the main fiber parameters lead to shifts of 320 to more than 500 nm which allows interesting molecular resonances imaging (≈ 1000-4000 cm…
Polarisation attraction and incoherent modulation instability in optical fibers
2006
This thesis, entitled « Polarisation attraction and incoherent modulation instability in optical fibers », presents a theoretical and experimental study of two new processes from the nonlinear optic in optical fibers domain. We introduce in the first chapter some theoretical notions useful for the comprehension of this work. Then, we demonstrate in the second chapter that it is possible to generate some modulation instability in optical fibers using a partially coherent optical beam. We highlight and observe the main properties of the phenomenon. We study the polarisation attraction in isotropic fibers process in the third chapter. Our work proves the existence of the phenomenon, and permit…