Raman solitons in transient SRS

We report on the observation of Raman solitons on numerical simulations of transient stimulated Raman scattering with small group-velocity dispersion. The theory proceeds with the inverse scattering transform (IST) for initial boundary-value problems and it is shown that the explicit theoretical solution obtained by IST for a semi-infinite medium fits strikingly well the numerical solution for a finite medium. We are able to explain this in terms of the rapid decrease of the medium dynamical variable (the potential of the scattering theory). The spectral transform reflection coefficient can be computed directly from the values of the input and output fields and this allows one to see the generation of the Raman solitons from the numerical solution. We confirm the presence of these nonlinear modes in the medium dynamical variable by the use of a discrete spectral analysis.