Autostabilisation de la phase acoustique dans un miroir Brillouin invers{\'e} en pr{\'e}sence d'une forte dispersion acoustique

We consider a counter-intuitive regime of stimulated Brillouin scattering in which the pump wave absorbs the phase defects of the Stokes wave, yielding a nonlinear self-stabilisation of the acoustic wave and a narrowing of the acoustic spectrum