基于光子晶体光纤的在线压力监测技术

On-Line Pressure Monitoring Method Based on Photonic Crystal Fiber

为了监测紧凑结构件的内部层间压力,提出一种采用新型材料保偏光子晶体光纤为敏感单元的嵌入式压力在线检测技术。建立了传感模型,采用Sagnac干涉技术组建检测系统,并进行了实验研究。通过实验验证,检测系统输出干涉峰值的移动量与光纤横向压力成线性关系,传感器可检测压力范围为0~10 k N,压力灵敏系数为0.441 4 nm/k N,传感器精度2.6%,且能明显观测到光纤上方垫层材料的松弛效应。试验验证敏感单元的重复性能良好,且温度敏感系数仅为-11.8 pm/℃,使得该类传感器具有良好的抗温度干扰性及工程实际应用性。

In order to monitor inter layer pressures in especial compact structure, an on-line and embedded pressure monitoring method is proposed using a new type of material as sensing element, that is polarization-maintaining pho- tonic crystal fiber（PM-PCF）. Sensing model is analyzed and measurement system based on Sagnac interferometer is set up to do the calibration experiments. The experiment results show that the output interference fringes of measure- ment system are shifted linearly with pressures, the dynamic range of sensor is 0 - 10 kN, sensing precision is 2.6%, pressure sensitivity is 0.441 4 nm/kN, the strain relaxation phenomenon of cushion on the PM-PCF can be observed obviously, and the good repeatability of sensing element is validated by the experiment. The sensor has better engi- neering practicability and capability to restrain interference brought up by fluctuation of environment temperature, which temperature sensitivity is only -11.8 pm/℃.