Search results for "supercontinuum"
showing 10 items of 128 documents
Supercontinuum spectral-domain ghost imaging
2018
International audience; Ghost imaging is a technique that generates high-resolution images by correlating the intensity of two light beams, neither of which independently contains useful information about the shape of the object. Ghost imaging has been demonstrated in both the spatial and temporal domains, using incoherent classical light sources or entangled photon pairs. Here we exploit the recent progress in ultrafast real-time measurement techniques to demonstrate ultrafast, scan-free, ghost imaging in the frequency domain using a continuous spectrum from an incoherent supercontinuum light source with random spectral fluctuations. We demonstrate the application of this technique to broa…
New developments in the study of optical parabolic pulses in normally dispersive fibers
2011
International audience; We report two recent studies dealing with the evolution of parabolic pulses in normally dispersive fibers. On the one hand, the nonlinear reshaping from a Gaussian intensity profile towards the asymptotic parabolic shape is experimentally investigated in a Raman amplifier. On the other hand, the significant impact of the fourth order dispersion on a passive propagation is theoretically discussed: we numerically demonstrate flat-top, coherent supercontinuum generation in an all-normal dispersion-flattened photonic crystal fiber. This shape is associated to a strong reshaping of the temporal profile what becomes triangular.
Study of supercontinuum sources based on tellurite glass optical fibers for mid-infrared absorption spectroscopy applied to gas sensing
2015
This work focuses on the development of mid-infrared supercontinuum light sources and their application for gas detection through absorption spectroscopy. The study of supercontinuum sources is based on nonlinear ultrashort pulse propagation in tellurite glass (80TeO2-10ZnO-10Na2O) and used in three different forms, namely a thin bulk sample, a microstructured suspended-core fiber, and a tapered suspended-core fiber. These technical means adapt themselves to distinct laser sources commercially available, thus optimizing the implementation of ultrawide-band infrared light sources. Experimental observations are compared to corresponding numerical simulations, thus pointing out the different u…
Thermodynamic approach of supercontinuum generation in photonic crystal fiber
2009
We show that the spectral broadening process inherent to supercontinuum generation may be described as a thermalization process, which results from the natural irreversible evolution of the optical field towards a thermodynamic equilibrium state.
Supercontinuum generation by cascaded intermodal Raman and FWM processes in step-index few-mode fibers
2018
International audience; This work shows that step-index few-mode fibers can be combined with a simple microchip picosecond laser to give a multi-octave spanning supercontinuum output by cascaded Raman scattering and intermodal FWM.
Propagation non-linéaire d'impulsions femtosecondes dans une fibre optique à bande interdite à cœur solide
2009
National audience; Nous décrivons une étude expérimentale et numérique de l'évolution non-linéaire d'impulsions ultrabrèves se propageant dans une fibre optique à bande interdite à coeur solide. Suivant le mécanisme de guidage employé, des dynamiques significativement différentes sont mises en évidence.
Multidimensional shaping of spatiotemporal waves in multimode nonlinear fibers
2019
Recent experiments have shown that nonlinear wave propagation in multimode optical fibers leads to complex spatio-temporal phenomena. In this talk, we introduce new approaches for the control and optimization of nonlinear beam reshaping in the spatial, temporal and spectral dimensions. The first approach applies to spatial beam self-cleaning the technique of transverse wavefront shaping, which permits to launch an optimized input mode combination, that results in the stable generation of a whole nonlinear mode alphabet at the fiber output. The second approach introduces a longitudinal tapering of the core diameter of multimode active and passive fibers, which permits to generate ultra-wideb…
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…
New theoretical and experimental concepts for frequency generation in optical fibers: modulation instability, pulsed Raman Laser and kinetic approach…
2009
Following a brief introduction to optical fibers, we combine the effect of modulational instability and Raman self-frequency shift to generate a frequency combs with a spectral width higher than 100 nm and a central frequency shifted towards higher wavelengths. Then, the stimulated Raman effect is used in a ring cavity coupled with nonlinear polarization rotation and polarization filtering. A pulsed regime is obtained at the wavelength of the first Stokes emission and presents a rich zoology of experimental dynamic pulsed regimes. A second main line of this manuscript considers the incoherent regime of supercontinuum generation. We show that under certain conditions, the spectral broadening…
Etude des sources supercontinuum à fibres transparentes dans le moyen infrarouge
2012
The work reported in this thesis deals with the study of the supercontinuum generation in fibers transparent in the mid-infrared. To generate a supercontinuum between 3 and 5 µm we compare different glass families such as fluoride glasses, tellurite glasses and chalcogenide glasses. These fibers are pumped with fiber lasers emitting at 2 µm with nanosecond or picosecond pulse duration. This wavelength allows us to reach the zero dispersion wavelength of the chalcogenide tapered fibers. We report supercontinuum generation up to 3800 nm in a fluoride glass fiber. A connection with 75 % of transmission is made between a ZBLAN and a SiO2 fiber. We also measured absorption lines of the methane a…