基于差分结构的光纤光栅应变传感器温度补偿

Temperature compensation of fiber Bragg grating strain sensor based on differential structure

针对基于差分结构的光纤应变传感器传统的温度补偿算法易产生测量误差的问题,本文将封装后的整个敏感结构一体化分析,通过实验标定得到光栅的温度敏感系数,简化了理论推导,并通过了应变实验测试。结果表明,进行温度补偿后,两光栅中心波长差与压强成线性变化,线性系数为0.7 pm/Pa,拟合度为0.999 5,能够有效抑制温度对波长的影响。

For the differential structure based optical fiber strain sensor,temperature and stress affect two gratings,and there is temperature and strain cross interference.The traditional temperature compensation algorithm does not consider the influence of the thermal expansion of the package structure on the center wavelength of the grating.There are some shortcomings in the theory of the algorithm,which are likely to cause measurement errors in the practical application of the project.In this paper,the sensitivity of the whole structure after encapsulation was analyzed,and the temperature sensitivity coefficient of the gratings was obtained by the experiment.The theoretical deduction was simplified and the strain measurement was carried out.The results show that after temperature compensation,the center wavelength difference between the two gratings is linearly related to the pressure.The linear correlation coefficient is 0.7 pm/Pa with a fit of 0.999 5,which can effectively suppress the effect of temperature on the wavelength.