Theory of phase conjugation quality under stimulated Brillouin scattering conditions in multimode waveguides

An analysis is made of the process of stimulated Brillouin scattering in the case when the length of a speckle element of a wide-angle pump field is of the order of the attenuation length of hypersound and the diffraction laws for the pump and signal fields differ because of a frequency shift. An equation for the structure of the conjugated wave is obtained and solved for increments and conjugation quality as a function of the profile of the angular spectrum of the pump.