基于啁啾光栅的温度与应变测量解耦方法研究

Research on decoupling method of temperature and strain measurement based on chirp fiber bragg grating

实际环境中光纤光栅存在对应变与温度测量交叉敏感问题,提出了利用啁啾光纤光栅(CFBG)进行双参数同时测量的方法。通过将CFBG胶封于等强度梁上,利用CFBG反射谱的中心波长与带宽对温度与应变的灵敏度差异,组成系数解耦矩阵,实现对应变与温度的同时测量。室温下,CFBG的中心波长与带宽随应变变化的灵敏度分别为0. 79、1. 38 pm/με,线性度为0. 998 8、0. 999 3;在-20~60℃温度范围内,CFBG的中心波长与带宽随温度变化的灵敏度分别为22. 74、23. 97 pm/℃,线性度为0. 999 8、0. 997 0,表明使用单个CFBG可以实现同时测量应变与温度。

In the real environment,there is a cross-sensitivity problem between fiber grating strain and temperature measurement.This paper proposes a simultaneous measurement method of two parameters using chirp fiber grating sensor.By sealing chirp fiber bragg grating(CFBG)on the equal-strength beam,the difference between the sensitivity of the center wavelength and the bandwidth of the CFBG reflection spectrum to temperature and strain is used to form a coefficient decoupling matrix,which can achieve simultaneous measurement of the corresponding change and temperature.At the room temperature,the sensitivities of CFBG center wavelength and bandwidth with strain are 0.79 and 1.38 pm/με.The corresponding linearity values are 0.998 8 and 0.999 3.Among the temperature range of-20~60℃,the sensitivities of the central wavelength and bandwidth of CFBG with temperature are 22.74 and 23.97 pm/℃.The linearity values are 0.999 8 and 0.997 0.Experimental results show that the simultaneous measurement of strain and temperature can be achieved using one single CFBG.