Abstract : Supercontinuum light generation is one of the most spectacular outcome of modern nonlinear optics as it possesses the spatial properties of a laser combined with an ultra-broad bandwidth spanning more than two octaves. In particular, small core microstructured fibres combined with femtosecond laser pulses have proven to be the most efficient way for supercontinuum generation. This thesis provides a comprehensive review of the different physical mechanisms leading to the generation of these spectra in optical fibres, paying a special attention to the nanosecond and continuous-wave (cw) pumping scheme. We then investigate both numerically and experimentally cw modulation instability in the zero-dispersion wavelength region of conventional optical fibres. Our results reveal a symmetry breaking dynamics in the modulation instability spectra associated with the generation of dispersive waves that are a consequence of soliton fission. We then describe a novel convenient technique to allow the accurate measurement of the dispersion coefficients till fourth-order of single-mode optical fibres. The proposed method is based on a careful spectral analysis of modulation instability occurring in both normal and anomalous dispersion regime and the associated dispersive waves. We then demonstrate a 1000-nm wideband all fibre-format supercontinuum source by use of a highly nonlinear fibre and a self-Qswitched fibre laser. Besides we experimentally study a new regime for supercontinuum generation in the nanosecond pulsed regime using a microstructured optical fibre with two zero-dispersion wavelengths. Pumping at 1535 nm around the second zero dispersion yields a nearly flat SC over 1350–1700 nm. The interplay between the effects of modulation instability and stimulated Raman scattering are described through simple phasematching relations. Cascaded anti-Stokes Raman generation due to phase-matching allowed by the groupvelocity dispersion is also reported. We finally report visible and infrared supercontinuum generation by dual nanosecond pumping near the two zero dispersion wavelengths of the same microstructured fibre. The resulting spectrum extends from 550 nm to wavelengths higher than 1950 nm.