In this work, a new type of high temperature fiber grating diaphragm pressure sensor is described, including the physical design structure, in-depth analysis of optical response to changes in pressure, and a discussion of the temperature compensation method. Mathematical model of high-temperature compressive shape change and normal-temperature compressive shape change is built, and effective temperature compensation method is proposed, which can both contribute to solve temperature interference of pressure sensor at high temperature. In addition, the simulation computation is conducted for the external encapsulation of the sensor under the high-temperature and pressure according to the design model. Through analysis and comparison of data affecting the changing position of grating signal, the correctness of the simulation result is verified by the development of the prototype. The temperature compensation method is proposed to realize pressure measurement of sensor with a relative error below 4.6%F.S. and range to 50 MPa in the environment of 300, which meets with the safety research requirement of the cartridge system.

For the requirement of pressure detection in high temperature environments, this paper presents a fiber Bragg grating (FBG) based pressure sensor with a simple structure. The structural model of the sensor has been established with the consideration of a sensing principle and a small deflection effect of the circular membrane. The finite element analysis has been employed to validate the rationality of the sensor structure design and realize the digital simulation of the theoretical model. Through the analysis, the selection of packaging materials, the design of structural parameters and the pressure and temperature calibration of the developed sensor has been performed. The encapsulation of the sensor at high temperatures has been improved based on the theoretical analysis, simulation and testing, which proves the effectiveness of the sensor for pressure measurement at high temperatures of 100 °C~250 °C. The study provides a feasible sensing device for high-temperature pressure detection.