Sensing Distance Enhancement in OFDR Using Multi-Arms Interferometer Phase Noise Compensation Method

We proposed the multi-arms interferometer phase noise compensation (MAI-PNC) method in optical frequency domain reflectometry (OFDR) sensing system for enhancing the phase noise compensation performance on the whole length of sensing fiber and increasing the sensing distance. The remaining phase noise along sensing fiber is mitigated to a lower level, and effective sensing distance is increased with the compensation of phase noise. The origin of remaining phase noise is explained in theory, with analysis of its distribution along sensing fiber. The OFDR strain sensing system with the proposed method is capable of sensing strain up to 3000 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i>ϵ, with a spatial resolution of 2 cm. Compared to conventional phase noise compensation, the proposed multi-arms interferometer phase noise compensation method increases the effective sensing distance from 104 m to 338 m.