He Xiangge, Xie Shangran, Liu Fei, Cao Shan, Gu Lijuan, Zheng Xiaoping, Zhang Min
Opt Lett. 2017 Feb 1;42(3):442-445. doi: 10.1364/OL.42.000442.
We demonstrate a novel type of distributed optical fiber acoustic sensor, with the ability to detect and retrieve actual temporal waveforms of multiple vibration events that occur simultaneously at different positions along the fiber. The system is realized via a dual-pulse phase-sensitive optical time-domain reflectometry, and the actual waveform is retrieved by heterodyne phase demodulation. Experimental results show that the system has a background noise level as low as 8.91×10 rad/√Hz with a demodulation signal-to-noise ratio of 49.17 dB at 1 kHz, and can achieve a dynamic range of ∼60 dB at 1 kHz (0.1 to 104 rad) for phase demodulation, as well as a detection frequency range from 20 Hz to 25 kHz.
我们展示了一种新型分布式光纤声学传感器，它能够检测并获取沿光纤不同位置同时发生的多个振动事件的实际时间波形。该系统通过双脉冲相敏光时域反射仪实现，实际波形通过外差相位解调获取。实验结果表明，该系统背景噪声水平低至8.91×10 rad/√Hz，在1 kHz时解调信噪比为49.17 dB，在1 kHz（0.1至104 rad）时相位解调动态范围可达约60 dB，检测频率范围为20 Hz至25 kHz。
