Sensitivity Calibration and Temperature Influence Analysis of High Temperature Resistant Fiber Optic Grating Sensors

This article completes the precise calibration of strain and temperature under high temperature conditions through the construction of a sensitivity calibration test bench for high-temperature resistant fiber Bragg grating sensors, and deeply explores the mechanism of temperature’s influence on sensor strain sensitivity. The test results show that the temperature sensitivity is 12.06pm/°C, the strain sensitivity is 0.3567pm/με, and the linearity of both is above 0.99. The repeatability is excellent, and the measurement results are stable with small dispersion and good stability. The study also provided temperature compensation formulas and parameters for strain measurement, which are suitable for strain monitoring applications in high-temperature environments. The experiment observed that with the increase of temperature, there is a slight nonlinear increase in strain sensitivity, which is attributed to five key factors: temperature changes causing thermal optical effects leading to spectral redshift, differences in material thermal expansion coefficients affecting strain transfer, nonlinear response of temperature and load superposition effects, poor degradation performance of interface constraints and adhesive layers at high temperatures, and nonlinear effects of prestressing. These findings provide scientific guidance for understanding and mitigating the impact of temperature on strain sensitivity, helping to optimize high-temperature sensor design and ensure reliable monitoring accuracy in extreme environments.