Generalized theory of SBS in multimode fiber amplifiers

Stimulated Brillouin Scattering (SBS) provides a major limitation on power scaling in high power fiber lasers and amplifiers. Using wavefront shaping in highly multimode fibers provides a promising avenue to suppress SBS while maintaining good beam quality. We present here a generalized theory for SBS in multimode fiber amplifiers. We find the Stokes susceptibility in terms of eigenmode expansions of the vector optical and acoustic wave equations. An analytical form of the relevant gain matrix is obtained in terms of modal overlap integrals. We will discuss wavefront shaping strategies to suppress SBS based on the properties of the gain matrix.