Influence of the spatial phase locking on amplification of pump-correlated Stokes fields in stimulated Brillouin scattering in a light guide

A theoretical method is proposed and used to calculate the gain increments and the spatial structure of scattered Stokes radiation. An allowance is made for distortions of two types: pump-uncorrelated noise and what are called rotated modes. It is shown that the latter are locked in a spatial resonance with the central reversed (phase-conjugated) mode. Such locking can occur in phase and in antiphase, with corresponding increments higher and lower than the Gaussian value of 2. The quality of wavefront reversal is estimated for a typical experimental situation.