Zhou Xiao, Wang Feng, Liu Zhen, Lu Yanqing, Yang Chengyu, Zhang Yixin, Shao Liyang, Zhang Xuping
Opt Express. 2022 Aug 1;30(16):29117-29127. doi: 10.1364/OE.463127.
The multi-parameter sensing is in great demand for comprehensive recognition in various application scenarios. We demonstrate a distributed optical fiber sensor (DOFS) for simultaneous vibration and temperature/strain sensing based on the integration of Brillouin optical time-domain reflectometry (BOTDR) and phase-sensitive optical time-domain reflectometry (Φ-OTDR). A double heterodyne detection configuration is set up to receive the Rayleigh scattering and Brillouin scattering simultaneously, which can enhance the signal-to-noise ratio (SNR) and reduce the polarization fading noise for the Brillouin signal at the same time. Most components in the setup are multiplexed for the Brillouin and Rayleigh signals. The overall cost is much lower than the summation of the BOTDR and the Φ-OTDR setup. In experiments, the setup is capable of measuring temperature change near the end of the 49.9 km long fiber with 0.381 MHz measurement uncertainty and restore different vibration patterns correctly by demodulating the phase variation of Rayleigh scattering signal, owning a 20 m spatial resolution. The sampling rate of the vibration measurement is 1.8 kHz, and the achieved dynamic strain resolution is 1.235 nɛ/√Hz with 100 Hz vibration.
多参数传感在各种应用场景中对于全面识别有着巨大需求。我们展示了一种基于布里渊光时域反射仪（BOTDR）和相敏光时域反射仪（Φ-OTDR）集成的用于同时进行振动和温度/应变传感的分布式光纤传感器（DOFS）。建立了一种双外差检测配置，用于同时接收瑞利散射和布里渊散射，这可以提高信噪比（SNR）并同时降低布里渊信号的偏振衰落噪声。该装置中的大多数组件对布里渊信号和瑞利信号进行复用。总体成本远低于BOTDR和Φ-OTDR装置的总和。在实验中，该装置能够以0.381 MHz的测量不确定度测量49.9 km长光纤末端附近的温度变化，并通过解调瑞利散射信号的相位变化正确恢复不同的振动模式，空间分辨率为20 m。振动测量的采样率为1.8 kHz，在100 Hz振动时实现的动态应变分辨率为1.235 nɛ/√Hz。
