Research on Coherent Rayleigh Backscattering and Signal Processing Method in Phase-Otdr

There have been a number of papers focusing on fiber distributed sensing with coherent Rayleigh backscattering published. However, up to now, very limited research articles on investigation of coherent Rayleigh backscattering signal waveform and its physical mechanism have been reported. This paper first proposes a theoretical derivation to illustrate coherent Rayleigh backscattering waveform. The theoretical model is then proved with numerical simulation and experimental measurement. In addition, signal processing method is an important factor on the performance of a phase-sensitive OTDR system. An improvement of signal processing method, which is consisted of digital average, moving average and interval subtraction, with good effect on locating external perturbation is also introduced.