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.