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RESEARCH PRODUCT

New theoretical and experimental concepts for frequency generation in optical fibers: modulation instability, pulsed Raman Laser and kinetic approach of supercontinuum generation

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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 inherent to supercontinuum generation may be interpreted with the kinetic wave theory as a thermalization process, i.e. resulting of an irreversible natural process of the field to reach an equilibrium state. A cut-back experiment highlights some particular features of the thermalization process during the supercontinuum longitudinal evolution.