提出了一种基于微波光子滤波器的高分辨率光纤横向负载传感器。与传统的基于光谱分析的光纤传感器不同,本传感器的信号解调是在微波域内完成的。其工作原理是利用保偏光纤光栅(PMFBG)构建偏振稳定的双波长光纤环形激光器,微波信号经电光调制器调制到激光器输出的光波上,借助长距离光纤形成的时延,形成一个两抽头的微波光子滤波器。理论和实验研究表明,该滤波器的频率响应与PMFBG上所受的横向压力之间存在线性关系,通过测量滤波器的微波谐振频率的变化,即可还原出待测横向压力的大小。实验获得了9.87 MHz·N ^-1的高灵敏度,实验结果与理论分析一致,证实了该方法的可行性。

A high-resolution transverse load fiber sensor based on microwave photonic filter (MPF) is proposed. It is different from the conventional fiber sensors based on spectral analysis because the signal demodulation is finished in the microwave domain. The working principle is as follows. With the polarization-maintaining fiber Bragg grating (PMFBG), a dual-wavelength ring fiber laser with a stable polarization is constructed. The microwave signal is modulated on the laser output and a MPF with two taps are formed with the time delay introduced by the long distance fiber. The theoretical and experimental results show that there exists a linear relationship between the frequency response of this filter and the transverse force on the PMFBG. The transverse force to be measured can be retrieved by the detection of the resonance frequency shift of this filter. In addition, in the experiment, a high sensitivity of 9.87 MHz·N -1 is obtained. The consistency between the experimental and theoretical results confirms the feasibility of this method.