Suppression of Signal Fluctuation in Brillouin Optical Correlation Domain Analysis System Using Polarization Diversity Scheme

We demonstrate the suppression of polarization-dependent gain fluctuation in a Brillouin correlation domain analysis system based on a polarization diversity scheme. Probe waves with two orthogonal polarization states are alternatively propagated and the Brillouin gain is calculated using their root sum square so as to compensate for the effect of the polarization state change of pump and probe waves. The improvement is confirmed by a successful measurement of strain distribution along a 100-m optical fiber with large local birefringence