Signal-to-noise ratio enhancement of phase-sensitive optical time-domain reflectometry based on power spectrum analysis

A location technique based on power spectrum analysis for the phase-sensitive optical time-domain reflectometry is proposed. The frequency characteristics of the backscattered signal at a time interval over the sensing fiber are provided to discriminate the disturbance region from other regions. Compared with conventional location techniques, the proposed method significantly enhances the signal-to-noise ratio (SNR). Therefore, it can provide a high-performance and cost-effective solution avoiding the use of the laser with super low-frequency drift. Although the frequency drift of the laser utilized in the experiment is 230 MHz/min, the average SNR is improved to be 20.3 dB and the maximum location error is 100 m over the monitored length of 9 km during 20 experiments.