DISPERSION AND SOLITON PROPAGATION IN STIMULATED RAMAN-SCATTERING

I discuss the role of group-velocity dispersion when a soliton propaga tes in a Raman-active medium. Using a modified beam-propagation method , I generate a pump soliton by inducing a phase shift of order ir in a n input Stokes seed. As the pulses propagate with different velocities because of the frequency dependence of the refractive index, pulse wa lk-off effects cause the soliton to decay and to break up. This gives rise to a new effect: the generation of a Stokes pulse whose width is comparable with the pump soliton width and whose height may be a facto r of 2 larger than the maximum input pump field amplitude.