Physical origin of dynamical stimulated Brillouin scattering in optical fibers with feedback

The role of spontaneous scattering and nonlinear refraction on the nonlinear dynamics of stimulated Brillouin scattering with feedback is investigated. We find that feedback suppresses stochasticity in the amplification process of the Stokes emission, giving rise to deterministic behavior, the forms of which are found to be critically dependent on the strength of the nonlinear refraction, which is shown to depend on the polarization-preserving properties of the medium. Our results provide an explanation of the chaotic dynamics observed in polarization scrambled fibers and also account for the simpler forms of dynamical behavior reported using polarization-preserving fibers. © 1995 The American Physical Society.