An all-fiber diaphragm-based extrinsic Fabry–Perot sensor for the measurement of pressure at ultra-low temperature

Abstract

An all-fiber diaphragm-based extrinsic Fabry-Perot interferometer (EFPI) sensor for the measurement of pressure at ultra-low temperature is proposed and experimentally demonstrated. The sensor head is manufactured at the end of a single mode fiber (SMF) with a micro hole and a fiber diaphragm. By femtosecond (fs) laser micromachining, sensors with different sensitivities can be fabricated with different diameter of the micro hole and different thickness of the diaphragm. The deformation of the diaphragm has a linear relationship with the applied pressure. This EFPI is used to measure the pressure at temperature of -196℃ by monitoring the cavity length of the interferometer. Experiment results show the sensor exhibits good linearity within a pressure range from 0 to 7 MPa, and the pressure sensitivities at -196℃ during the process of pressure increasing and decreasing are 111.17 nm/MPa and 111.22nm/MPa, respectively. The proposed all-fiber pressure sensor can find applications in ultra-low temperature environment.

Process method of Si3N4 ceramic brazing sealed cavity for high-temperature application

“…In high-temperature environments, in situ and accurate pressure measurements are required for industrial applications, such as energy extraction, environmental monitoring, turbine engines, high-speed aircraft, and other aerospace applications ( Lü et al, 2018 ; Chen et al, 2022 ; Li et al, 2022 ; Zhang et al, 2022 ), to improve component conditions and ensure engine reliability ( Bonham et al, 2017 ; Miura et al, 2017 ; Han et al, 2020 ; He et al, 2021 ). Materials are crucial as the cornerstone of pressure sensors, as sensors made of ordinary materials cannot operate optimally in high-temperature environments.…”