Research on High-Temperature Resistant Strain Sensor Based on Fiber-Optic Fabry-Perot Structure

In order to develop a micro strain sensor suitable for mechanical measurement in the high temperature environment of the reactor first loop , based on the principle of optics, demodulation principle and packaging technology of the fiber-optic Fabry-Perot (FP) structure, the thermal-mechanical coupling model of the sensor is proposed, a high temperature resistant strain sensor based on the fiber-optic FP structure and its demodulating system are designed, and its dynamic test is carried out in the normal temperature air, high temperature and medium pressure water environment. The research and test results show that the high temperature strain resistant fiber optic strain sensor and its demodulating system can operate stably in high temperature, medium pressure and water environment, and the measuring range of the strain sensor is 0~4000 με, the accuracy is 0.125%FS, and the speed of the demodulating system is 5 kHz. The high temperature resistant strain fiber optic strain sensor and its demodulating system designed in this study can be used to measure the strain in the high temperature environment of the reactor first loop, thus providing an effective monitoring method for the monitoring in the high temperature environment of the reactor reactor first loop.