基于Lyot滤波器和长周期光纤光栅的温度与应变的同时测量

提出了一种基于光纤干涉原理的同时测量温度和应变的传感器,通过在Lyot滤波器(LFF)中熔接一段长周期光纤光栅(LPFG)构成。其中LFF由在起偏器(PL1)和检偏器(PL2)中嵌入一段保偏光纤(PMF)构成。实验结果表明,LFF的干涉谱和LPFG的谐振峰对温度和应变有不同的响应灵敏度,因此可利用敏感矩阵实现对温度和应变的同时测量。实验测得LFF和LPFG的温度灵敏度分别为-1.3173nm/℃和0.0604nm/℃,应变灵敏度分别为-0.0185nm/με和-0.0004nm/με。温度和应变的测量精度分别为±1℃和±25με。该系统采用线性结构,结构简单、易于实现,具有较高的灵敏度和稳定性,同时测量结果具有良好的线性度。

Simultaneous Measurement of Temperature and Strain Based on a Long-Period Fiber Grating Combined with a Lyot Fiber Filter in a Linear Configuration

A novel sensor for simultaneous temperature and strain measurement based on fiber interference is proposed. The sensor is formed by incorporating a long-period fiber grating (LPFG) inside a Lyot fiber filter (LFF), in which the LFF can be constructed by placing a polarization maintaining fiber (PMF) between two polarizers (PL) with the primary axis of the fiber rotated 45° relative to the polarizer axes. Due to the different responses of the LFF and LPFG to temperature and strain variations, it is possible for the proposed fiber sensor to measure temperature and strain simultaneously by use of a well-conditioned sensitivity matrix equation. The experimental temperature sensitivity coefficients of LFF and LPFG are -1.3173 nm/℃ and 0.0604 nm/℃, respectively. The strain sensitivity coefficients achieve -0.0185 nm/με and -0.0004 nm/με, respectively. A sensing resolution of ±1 ℃ in temperature and ±25 με in strain has been experimentally obtained. The experimental results are in good agreement with the theoretical analysis. Furthermore, this linear configuration is simple and easy to achieve, and has high stability and sensitivity.