Self-Phase Modulation and Optical Pulse Compression Influenced by Stimulation Raman Scattering in Fibers

We have investigated experimentally the influence of stimulated Raman scattering, under conditions of pulse walk-off, on the propagation of mode-locked 1.06microns pulses in single-mode, polarization-preserving fibers and on their subsequent pulse comparrison. Intense stimulated Raman scattering preferentially depletes (and steepens) the leading edge of 1.06microns pump pulses and clamps the pump pulse energy. Subsequent self-phase modulation of the reshaped pump leads to nonsymmetric spectral broadening and to a nonlinear chirp.