Polarization dependent Brillouin frequency shift fluctuation induced by low birefringence in single mode fiber

The polarization dependent fluctuation of Brillouin frequency shift (BFS) of stimulated Brillouin scattering (SBS) in practical single mode fibers (SMFs) is reported. The phenomenon is actually caused by the interference of the low birefringence in SMF with the SBS spectral polarization spreading of the signal light. The performance of the polarization dependent BFS fluctuation is studied by simulation and confirmed with agreeable experimental results.