Control of the Stokes frequency shift in a loop stimulated-Brillouin-scattering laser

The eigenfrequencies of a loop stimulated-Brillouin-scattering (SBS) laser and their dependence on the loop length were determined experimentally. The conditions under which a change in the loop length resulted in continuous frequency tuning over the whole gain profile were found. A theoretical model based on a mode theory of SBS with spatially inhomogeneous pumping was found to be in qualitative and quantitative agreement with the experimental results.