We describe a time-dependent model that describes the evolution of stimulated Brillouin scattering (SBS) in fibers under phase-modulated pump conditions. In order to accurately model fast modulations, the triply-coupled system of differential equations describing the interaction of SBS through optical and phonon fields is solved numerically. SBS is initiated from noise by using a Langevin term. We initially consider single-frequency sinusoidal modulations as a function of modulation amplitude and frequency. We then investigate the effects of SBS mitigation when a single-frequency seed is phase modulated with a broad-band white-noise source (WNS).© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.