Theoretical and Experimental Analysis of $\Phi $ -OTDR Based on Polarization Diversity Detection

Statistical characteristics of location related intensity distribution in phase-sensitive optical time-domain reflectometry (
$\Phi $
-OTDR) are theoretically analyzed and experimentally demonstrated. The polarization diversity scheme is adopted into the
$\Phi $
-OTDR with a coherent detection scheme to effectively mitigate the polarization fading effect. A real distributed sensing application for simultaneous multi-events vibration detection can thus be achieved along each position of the sensing fiber with more reliable vibration detection results. The experiment shows that the signal-to-noise ratio of two vibration signals is simultaneously enhanced by 10.9 and 8.65 dB compared with the results obtained by a conventional coherent detection scheme.