高分辨率光纤光栅温度传感器的研究

报道了一种具有高分辨率和高效且价廉的解调系统的光纤布拉格光栅(FBG)温度传感器。提出了光纤光栅的金属槽封装技术，以提高传感光栅的温度灵敏性。研究了金属槽封装光栅的温度灵敏性，理论分析和实验结果表明，封装光栅的温度灵敏系数比普通裸光栅提高了3．6倍。系统利用一长周期光栅(LPG)作为线性滤波器，宽带光源经此长周期光栅调制后入射到传感光栅，可解调布拉格传感光栅的波长位移。理论分析与实验结果一致，系统可达到的温度分辨率为0．02℃。

A novel fiber Bragg grating (FBG) temperature sensor system with high resolution and low cost demodulation mechanism was proposed. The metal groove encapsulating technique for FBG sensor was developed to improve the temperature sensitivity of FBG temperature sensor. Coefficient of thermal-expansion of the encapsulated FBG sensor was studied. The comparison of results between encapsulated FBG sensor and bare FBG sensor indicted that the temperature sensitivity of encapsulated FBG sensor is improved and the sensitivity coefficient is 3.6 times as much as that of bare FBG sensor. A long period grating (LPG) was used as linear response filter to convert wavelength into intensity for interrogation. In experiment, a broadband source was modulated by the LPG and then it illuminated the sensor grating, which could interrogate the wavelength shifts of sensor system. The experimental results agreed well with the theoretical analysis. The FBG temperature sensor realized a high resolution of 0.02 ℃.