Stochastic dynamics of stimulated Brillouin scattering in an optical fiber.

We have investigated the statistical properties of stimulated Brillouin scattering (SBS) in a single-mode optical fiber. Gain narrowing of the Stokes spectrum is observed as the input laser power is increased, and large stochastic fluctuations are observed in the Stokes output intensity. The experimental results can be described well by a theoretical model that includes the spontaneous nature of the initiation of SBS.