新型光纤光栅温度自补偿方法理论分析

为了解决光纤光栅作为应变传感器使用时的温度应变交叉敏感问题，提出了一种全新的光纤光栅温度补偿方法，该方法最大特点是利用一个光纤光栅同时实现了温度自动补偿与应变测量。该方法基于材料的热应力原理，简称为基于材料热应力的光纤光栅温度补偿方法。通过理论分析表明:温度灵敏度系数与应变灵敏度必须精确测定，否则会影响结构设计；应变元件与温度补偿元件的面积之比对温度补偿效果很大，原则上应小于0.5，因此结构半径的加工误差对温度补偿影响很大。应变元件与温度补偿元件的长度比对温度补偿效果基本可忽略，因此，原则上在不影响温度补偿效果的前提下，尽量提高温度补偿元件与应变元件的长度比。

Theory analysis of novel fiber Bragg grating temperature compensated method based on thermal stress

To solve the problem of cross sensitivity of fiber Bragg grating (FBG), a novel FBG temperature-compensated method is proposed by using a single FBG adopting a special compensated method. The basic operating principle of the temperature compensation exploited in this study is based on the material thermal stress. The relationship between strain and temperature response of FBG is theoretically analyzed. The analysis results show that the temperature and strain sensitivity coefficient should be accurately measured, the errors of mechanical process have quite great influence on the temperature-compensated results, and the cross section ratio of strain element to temperature compensated element should be less than 0.5, the length ratio of strain element to temperature compensated element can negligibly affect the temperature-compensated results. Thus, it is anticipated that length ratio should be increased as soon as possible on the base of non-influence on the temperature-compensated results.