Search results for "fibre optique"
showing 10 items of 19 documents
Collision de similaritons optiques dans un amplificateur optique fibré Raman
2005
National audience; Nous abordons les aspects théoriques et expérimentaux de la génération et propagation de deux similaritons optiques de fréquences centrales différentes dans un amplificateur optique fibré Raman à dispersion normale. Nous observons les effets intervenant durant la collision des deux similaritons: un battement sinusoïdal apparaît dans la zone de recouvrement temporel des impulsions et des effets de la modulation de phase croisée modifient le spectre des similaritons. Les similaritons retrouvent néanmoins, après collision, leurs caractéristiques paraboliques.
Ondes scélérates et statistiques extrêmes dans les systèmes optiques fibrés
2011
This thesis deals with extremes statistics which has become an attractive subject in optics since a comparison with oceanic rogue waves has been proposed at the end of 2007. We report some potential mechanisms stimulating the rogue wave formation in the context of guided propagation of light in optical fibers. In a first part, we explore optical rogue waves in supercontinuums generated by fourth-order modulation instability and we propose a stabilization method based on the use of two continuous seeds. Then, we present a detailed study on Raman fiber amplifiers where we determine the conditions of emergence of giant structures : in presence of a partially incoherent pumping wave, a quasi-in…
Fourth-order cascaded Raman shift in AsSe chalcogenide suspended-core fiber pumped at 2 μm
2011
International audience; Cascaded Raman wavelength shifting up to the fourth order ranging from 2092 to 2450nm is demonstrated using a nanosecond pump at 1995nm in a low-loss As38Se62 suspended-core microstructured fiber. These four Stokes shifts are obtained with a low peak power of 11W, and only 3W are required to obtain three shifts. The Raman gain coefficient for the fiber is estimated to (1.6 +-0.5)x 10e−11 m/W at 1995nm. The positions and the amplitudes of the Raman peaks are well reproduced by the numerical simulations of the nonlinear propagation.
Suspended core tellurite glass optical fibers for infrared supercontinuum generation
2011
International audience; We report the fabrication and characterization of tellurite TeO(2)-ZnO-Na(2)O (TZN) microstructured suspended core optical fibers (MOFs). These fibers are designed for infrared supercontinuum generation with zero dispersion wavelength (ZDW) at 1.451 mu m. The measured losses at this wavelength are approximately 6 dB/m for a MOF with a 2.2 mu m diameter core. The effective area of a particular fiber is 3.5 mu m(2) and the nonlinear coefficient is calculated to be 437 W(-1)km(-1). By pumping a 20 cm long fiber at 1.56 mu m with a sub-nj femtosecond laser source, we generate a supercontinuum (SC) spanning over 800 nm in the 1-2 mu m wavelength range.
Elaboration of multimaterial optical fibers with electro-optical functionalities
2022
The emergence of multimaterials optical fibers is of tremendous technological interest in photonics to combine the remarkable properties of glasses with those of other materials such as metals or polymers in order to form a fully integrated fiber optical system with multiple functionalities. Among these hybrid fibers, the development of fibers combining both optical signal and simultaneous electrical transport function could bring alternative interesting solution in many fields such as telecommunications, medicine or sensing. The drawing of architectures merging electrical and optical features in a unique elongated wave-guiding structure will enable to develop electro-optical functionalitie…
ultra-short pulse propagation at 160-Gb/s in dispersion managed optical fiber lines
2004
This thesis presents a study on ultra-short pulse propagation at 160-Gb/s in dispersion managed optical fiber lines. In a first part, we describe the experimental design of a SHG-FROG setup able to characterize high repetition rate pulse trains. Secondly, we demonstrate the efficiency of multiple four wave mixing phenomenon for the generation of a 160-GHz pulse train through the compression of a sinusoidal beat-signal. Then, in order to compare the experimental and theoretical results, we present the development of an optical fiber characterization benchtop based on modulational instability. In the last part of this thesis, we built and compare several recirculating loop setups. On the one …
Evolutionary algorithm for fiber laser in ultrashort pulse regime
2016
This thesis deals with the generation of ultrashort pulses within a fiber laser cavity through the automatic optimization of its parameters by an evolutionary algorithm. The interest of this subject comes from the difficulty to systematically explore dynamics in a large domain of experimental parameters. We have shown that it is possible to implement an evolutionary algorithm on fiber laser cavity with appropriate precautions. We have experimentally demonstrated for the first time the mode locking of a laser cavity only using the optimization of polarization controllers through an automatic and self-learning procedure. We also have demonstrated that selecting the mode locking from it radio-…
CARACTÉRISATION ET MODÉLISATION DE PEIGNES DE FRÉQUENCES KERR DANS DES CAVITÉS LASER BRILLOUIN À FIBRE
2022
Nous étudions une cavité en anneau non réciproque simple et reconfigurable pour générer des peignes de fréquences optiques accordables. Nous démontrons que des peignes cohérents peuvent être obtenus en exploitant finement la rétrodiffusion Brillouin stimulée et le mélange à quatre ondes en cascade dans la cavité à fibre non-linéaire.
Similaritons in optical fiber Raman amplifiers
2005
This thesis presents the generation of optical similaritons in a normally dispersive Raman amplifier at telecom wavelengths. The pulses experimentally characterized by FROG technique exhibit a parabolic intensity profile with a linear chirp, in good agreement with results of numerical simulations.Several theoretical features of the similaritons have been experimentally studied. The dynamics of two similaritons with same or different central wavelengths is also investigated: similaritons are robust against collisions, whereas the interaction of similaritons leads to the generation of high-repetition rate dark soliton train.The similariton properties have been finally applied into three field…
Supercontinuum generation in chalcogenides : application to gas spectroscopy in atmospheric band III
2023
This thesis work aims to contribute to the development of new fiber sources emitting over a wide range of wavelengths in the IR, in particular to detect greenhouse gases in the mid-infrared range. Our spectroscopy results with nitrous oxide N2O and methane CH4 are obtained in band III. To achieve this, the generation of supercontinuum (SC) covering band III was made possible by using chalcogenide optical fibers, purified and free of highly toxic elements according to REACH regulations, in particular arsenic and antimony. The fibrable vitreous composition belonging to the Ge-Se-Te ternary system fits perfectly into the context of sustainable development, it is the one that has been identifie…