The round trip time of the light pulse limits the maximum detectable frequency response range of vibration in phase-sensitive optical time domain reflectometry ({\phi}-OTDR). We propose a method to break the frequency response range restriction of {\phi}-OTDR system by modulating the light pulse interval randomly which enables a random sampling for every vibration point in a long sensing fiber. This sub-Nyquist randomized sampling method is suits for detecting sparse-wideband-frequency vibration signals. Up to MHz resonance vibration signal with over dozens of frequency components and 1.153MHz single frequency vibration signal are clearly identified for a sensing range of 9.6km with 10kHz maximum sampling rate.
@article{arxiv.1701.01522,
title = {Breaking through the bandwidth barrier in distributed fiber vibration sensing by sub-Nyquist randomized sampling},
author = {Jingdong Zhang and Tao Zhu and Hua Zheng and Yang Kuang and Min Liu and Wei Huang},
journal= {arXiv preprint arXiv:1701.01522},
year = {2017}
}