Coherent Φ-OTDR based on polarization-diversity integrated coherent receiver and heterodyne detection

We demonstrate a novel distributed optical fiber sensor system based on phase-sensitive optical time-domain reflectometry (Φ-OTDR). Both the phase and the amplitude of the Rayleigh scattering (RS) light can be demodulated based on I/Q demodulation and heterodyne detection using commercial available 100G integrated coherent receiver (ICR). The polarization fading problem in Φ-OTDR can be avoided by considering the RS signal from both polarizations. The dynamic strain sensing with a sensing range of 9.8 km and a spatial resolution of 15 m is experimentally demonstrated.