Realisation et caracterisation d'un laser haute-puissance tout-fibre par cascades Raman (French text)

This work consists in the realization and characterization of a high-power Raman fiber lasers in a linear configuration.; Four lasers were demonstrated: a laser emitting at 1117 nm using the 4% reflections at the air-glass interface (LR1), a second laser emitting at 1117 nm (LR2), a third laser emitting at 1240 nm (LR3) and a laser emitting at 1480 nm (LR4). The first two lasers (LR1, LR2) use Corning's PureMode1060(TM) germanium-doped silica fiber whereas the two others use a phosphorous-doped fiber manufactured by the Institut national d'optique (INO). The fiber Bragg gratings used as reflectors in LR2, LR3 and LR4 are written in hydrogenated PureMode1060(TM) fiber.; The Raman gain spectrum of P-doped fibers (PDF) is known to exhibit, in addition to the pure silica response, a strong 40 THz frequency-shifted Stokes peak relative to the pump. This large shift allows reducing of the number of cascades in Raman lasers using nested cavities. The Raman gain spectra of two phosphorous-doped silica fibers were characterized. The experimental values of the Raman gain coefficient obtained are compatible with published results.; In addition, the experimental results showed that the idealistic monochromatic model generally encountered is unsuited to account for the spectral characteristics of Raman fiber lasers using fiber Bragg gratings.