Polarization changes by the soliton propagation in a planar waveguide

Summary form only given.The soliton phenomenon allows a stable and self-guided propagation of a laser beam to be obtained in a Kerr medium if the power conditions are fulfilled. This phenomenon has been obtained in planar waveguides and in bulk media, where we reconstruct by interferences a two-dimensional propagation. It appears that this propagation becomes unstable when the distance is large or when the beam power has to be increased. The nonlinear effects are then accentuated, and a spectral study has shown the role of the stimulated Rayleigh scattering on this propagation. We show here that another instability arises on the output beam polarization at the soliton power threshold.