采用双折射光纤设计分布式应力传感器

Design of a Distributed Stress Sensor Using Bi-refringence Optical Fiber

采用扫描式迈克尔逊白光干涉仪对应力场引起的高双折射保偏光纤(PMF)内部的分布式偏振模式耦合进行定量测试和理论分析。由偏振模耦合的强度计算应力的大小,通过由双折射引起的2个正交的偏振模的光程差计算应力的位置。提出了分布式光纤应力传感器的结构设计。该传感器可实现1km的测量范围,对应力作用点的空间位置测试精度可达到mm量级,对偏振模耦合强度测试可达到-80dB的灵敏度。

The distributed polarization mode coupling caused by stress field in high-birefringence polarization-maintaining optical fiber (PMF) was measured and analyzed using a scanning Michelson white light interferometer. The magnitude of the stress was calculated according to the intensity of the polarization mode coupling. The location of the stress was determined by calculating the optical path difference of the two orthogonal polarization modes. The structure of this distributed optical fiber sensor was proposed based on the theoretical analysis and numerical simulation. The measurement range is 1 km. The spatial resolution of the stress is on the order of millimeters. And the sensitivity of polarization mode coupling is approximately -80 dB.