Spectral width of oscillations and ultimate sensitivity of phase-conjugation systems with multiple light-beam intersections

A theoretical analysis is made of the influence of the spontaneous scattering noise on parametric excitation of stimulated Brillouin scattering (SBS) in a system of intersecting laser pump and signal wave beams. The line broadening of parametric oscillation is calculated. A study is made of the limit imposed on the sensitivity by excitation of a non-phase-conjugated SBS wave and also of the effects of the wave mismatch.