Search results for "Fibres optiques"
showing 10 items of 16 documents
Mid-infrared supercontinuum generation in chalcogenide and telluride fibers for sensor devices
2019
This thesis reports on the progress made during my PhD concerning supercontinuum generation and its application in two types of materials: chalcogenide and tellurite glasses. Concerning the chalcogenide axis, two new arsenic-free compositions are developed: Ge20Se60Te20 and Ge20Se70Te10. Thermal and optical properties of these two glasses are studied and two types of fibers are manufactured: a step-index fiber and a suspended core fiber. The generation of supercontinuum in these two fibres, pumped by an optical parametric amplifier, gives competitive results compared to the current state of the art of supercontinuum generation in chalcogenide fibres. Supercontinuums widening between 2 and 1…
Génération de supercontinuum infrarouge et enjeux de vieillissement au sein de fibres optiques à coeur suspendu hautement non linéaires en verre de c…
2014
The work reported in this thesis deals with the fabrication of suspended core chalcogenide microstructured optical fibers (MOFs) for supercontinuum generation (SCG) beyond 6 μm. In this context, As2S3-based suspended-core MOFs were fabricated under vacuum, and loss threshold of 1-2 dB/m at 2.9µm were systematically registered. In addition, MOFs were designed with core diameter ranging from 1.5 to 3.5µm, allowing therefore to control the MOF's dispersive properties and to shift corresponding zero dispersion wavelength to 2.0-2.5 µm range. SCG experiments were performed by pumping the fabricated MOFs in their anomalous dispersion regime by means of tunable femtosecond laser source. Simultaneo…
Modulational instability and domain wall solitons in optical fibers
2000
The first part of this thesis presents some theoretical and experimental results about modulational instability and domain wall solitons in bimodal fibers.In the second part is devoted to the interaction of counter-propagating waves in an isotropic optical fiber
Study of new tellurite glasses in the TeO2-ZnO-La2O3 (TZL) system for the manufacturing of mid-infrared multimaterial optical fibers and specialty op…
2023
This thesis work was carried out using tellurite glasses from the TeO2-ZnO-La2O3 (TZL) ternary diagram for optical fibers manufacturing. The choice to use this system is motivated by the ambition to improve the transmission of optical signals within oxide glasses for which absorption bands related to OH groups are present in the transparency window. A structural study is first carried out on these glasses by Raman spectroscopy in order to understand the influence of the composition on physicochemical properties (especially on optical and thermal properties) but also to estimate the ability of a vitreous matrix to reorganize when subjected to a thermal solicitation such as the preform-to-fib…
Te-As-Se glass microstructured optical fiber for the middle infrared
2009
International audience; We present the first fabrication, to the best of our knowledge, of chalcogenide microstructured optical fibers in Te-As-Se glass, their optical characterization, and numerical simulations in the middle infrared. In a first fiber, numerical simulations exhibit a single-mode behavior at 3.39 and 9.3 μm, in good agreement with experimental near-field captures at 9.3 μm. The second fiber is not monomode between 3.39 and 9.3 μm, but the fundamental losses are 9 dB/m at 3:39 μm and 6 dB/m at 9.3 μm. The experimental mode field diameters are compared to the theoretical ones with a good accordance.
Tellurites fibers for infrared supercontinuum sources : opto-geometric profiles and extrinsic absorptions management
2016
This PhD thesis work focuses on the synthesis and purification of vitreous materials used for the development of waveguides with varied profiles, dedicated to supercontinuum (SC) generation between 1 and 5 μm.Concerning the purification of tellurite glasses, several leads were followed, but best results are obtained for the purification of the TeO2-ZnO-Na2O glassy system by the means of zinc fluoride. Attenuation measurements performed on several meter-long single-index fiber samples reveal the nearly complete elimination of water-related absorptions between 3 and 4 μm (OH ions concentration lower than 1 ppm mass.). Such water-purified glasses were firstly dedicated to microstructured optic…
Fibres optiques à coeur supendu en verre d'oxyde de tellure et génération d'effets non linéaires dans l'infrarouge au-delà de 2 microns
2012
The work reported in this thesis deals with the fabrication of suspended core tellurite microstructured optical fibers (MOFs) for supercontinuum generation beyond 2 µm. In order to reach our aim, we first studied thermal and optical properties of TeO2-ZnO-R2O and TeO2-WO3-R2O (where R = Li, Na and K) glasses. The glass 80TeO2-10ZnO-10Na2O (molar %) has been chosen in order to make MOFs for characterization of the generated non linear optical effects. Synthesis performed under dry and oxidative atmosphere allowed us to reduce the hydroxyl groups concentration by a factor of 30 compared to fabrication in air atmosphere. Use of dehydrating agents (ZnF2 and TeCl4) allowed to reduce again the OH…
Wave dynamics and turbulence in multimode optical systems
2021
The subject of this thesis essentially focuses on the experimental and theoretical study of optical turbulence in different types of nonlinear media. The first part of the manuscript is devoted to the study of thermalization and condensation of optical waves during their propagation in graded-index multimode fibers. The analysis based on the wave turbulence theory reveals that the disorder inherent to light propagation in an optical fiber induces a significant acceleration of the process of optical thermalization, which can clarify the mechanism of certain regimes of spatial beam cleaning recently reported in the literature. We show experimentally that the optical field relaxes during its p…
Small-core chalcogenide microstructured fibers for the infrared.
2008
International audience; We report several small-core chalcogenide microstructured fibers fabricated by the "Stack & Draw" technique from Ge(15)Sb(20)S(65) glass with regular profiles. Mode field diameters and losses have been measured at 1.55 microm. For one of the presented fibers, the pitch is 2.5 microm, three times smaller than that already obtained in our previous work, and the corresponding mode field diameter is now as small as 3.5 microm. This fiber, obtained using a two step "Stack & Draw" technique, is single-mode at 1.55 microm from a practical point of view. We also report the first measurement of the attenuation between 1 and 3.5 microm of a chalcogenide microstructured fiber. …
Unified mapping of the dynamics of solitons in fiber-optic waveguides
2013
This thesis examines the dynamical behaviour of solitons which are affected, when entering a fiber-optic waveguide, by a slight distortion of profile as compared to the stationary profile in the guide. Our theoretical model combines the propagation equation of the electric field (Non-Linear Schrödinger Equation) and the system of equations of evolution of the physical parameters of the pulse (derived from the collective coordinates theory). We establish a general mapping which reveals an unsuspected diversity of dynamic behaviour around the stationary state of the pulse, in relation with the initial perturbation of the pulse's profile. This mapping establishes a classification of solitons i…