An In-line Fiber Optic Fabry-perot Sensor For High-Temperature Vibration Measurement

The monitoring of object vibration under high temperature environment is widely used in aerospace,oil and gas exploitation,chemical production and other fields,and the thermal performance evaluation of load-bearing structures is extremely important to safety in these fields.In previous studies,fiber-optic Fabry-Perot sensors have proven their application prospects in high-temperature environments.They have the characteristics of antielectromagnetic interference,anti-corrosion,and high accuracy.This article aims to design a low-cost,small-volume all-quartz optical fiber online high-temperature vibration sensor,which can be embedded in an object to achieve direct measurement of vibration,providing the necessary reference for the design of fiber optic sensors in the future.The main content of the paper includes:(1)This paper proposes an inline optical fiber Fabry-Perot sensor for vibration measurement under high temperature environment.A mass-spring-damper system is constructed by welding quartz sleeves with different inner and outer diameters on the optical fiber to detect vibration at high temperature.This paper elaborated the design idea of the sensor from the three aspects of optical demodulation design,dynamics design and thermodynamics design of the sensor and carried out the corresponding simulation.(2)Combined with the graphic programmable module of the carbon dioxide laser welding machine,the motor and laser are accurately controlled,and the preparation of the Fabry-Perot cavity,the integration of the mass system and the welding of the package shell are completed respectively.The high-efficiency processing of the sensor is achieved,with high consistency,and it is a method of mass production.(3)A high-temperature vibration test platform was built.The test results show that the inline optical fiber vibration sensor prepared in this paper has a resonance frequency of 165 Hz,a sensitivity of 11.57mv/g,a nonlinearity of 2.06%,and a temperature coefficient of 0.84pm/? The radial diameter of the sensor does not exceed 500?m,and the vibration can still be detected normally at a high temperature of 500?,which can provide the necessary reference for the design of the optical fiber farper sensor in the future.