Distributed intrusion detection based on combination of φ-OTDR and POTDR

A distributed optical fiber intrusion detection system, based on the combination of the phase-sensitive optical time-domain reflectometer (φ-OTDR) and the polarization optical time domain reflectometer (POTDR), is proposed and demonstrated. The wavelet transform method and peak-enhancing signal processing are used to de-noise the sensing data and achieve high SNR. Both the φ-OTDR and the POTDR share the same optical devices and work together to enhance the veracity of detecting and locating the intrusion perturbation. Experimental results show that perturbation detection with 100% veracity is achieved over a 14km long fiber link with a spatial resolution of 50m by means of the dual outputs from the φ-OTDR and the POTDR simultaneously.