Detailed studies of cw stimulated Brillouin scattering in single mode and multimode optical fibers

This study focuses on polarization and focusing properties of the pump radiation as possible sources of observed discrepancies. Preliminary experimental investigations of the polarization properties have shown approximately 2:1 polarized (65%) stimulated Brillouin scattering (SBS) outputs in the single mode fiber experiments, and 100% polarized SBS outputs in the multimode fibre experiments. Results show that pump and SBS polarizations can affect the effective SBS gains, and thus account for a significant portion of the observed discrepancies in the SBS thresholds. Results on pump focusing experiments are also presented along with theoretical models on various aspects of SBS in single-mode and multimode fibers.