A Dual-Cavity Fabry–Perot Interferometric Fiber-Optic Sensor for the Simultaneous Measurement of High-Temperature and High-Gas-Pressure

Yang Cui,Yi Jiang,Jie Hu,Lan Jiang,Tianmu Liu

doi:10.1109/access.2020.2991551

Yang Cui, Yi Jiang + Show 3 more

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https://doi.org/10.1109/access.2020.2991551

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Journal: IEEE Access	Publication Date: Jan 1, 2020
Citations: 31	License type: CC BY 4.0

Affiliation: Beijing Institute of Technology

Abstract

A fiber optic dual-cavity Fabry-Perot interferometer(DFPI) for simultaneous high- temperature and high-gas-pressure measurements is proposed and experimentally demonstrated. The proposed sensing structure consists of an extrinsic Fabry-Perot interferometer (EFPI) with a short piece of hollow core fiber (HCF) for gas pressure sensing, and an intrinsic Fabry-Perot interferometer (IFPI) made of photonic crystal fiber (PCF) for temperature sensing. The composite interference signal is filtered in the frequency domain to obtain two independent interference spectra, and then is demodulated by using white light interferometry (WLI). The experimental results show that the sensor exhibits good linearity over a temperature range from 40 to 1000°C with a cavity-length temperature sensitivity of 25.3 nm/°C, and a pressure range from 0 to 10 MPa with a cavity-length pressure sensitivity of 1460 nm/MPa at 40°C. This proposed sensor are light-weight and small, and it has a compact structure and a high temperature resistance.

Highlights

In recent years, there has been an urgent demand for temperature and pressure measurements in the high-temperature and high-gas-pressure environments of turbine engines, highspeed aircraft, and other aerospace applications
Optical fiber sensors have the advantages of high temperature resistance, electromagnetic interference immunity, small volumes and passive sensing, making them suitable for measuring temperatures and gas pressures in some extreme environments
The sensor structure is an extrinsic Fabry–Perot interferometer (EFPI) made of hollow core fiber (HCF) cascaded with an intrinsic Fabry–Perot interferometer (IFPI) made of photonic crystal fiber (PCF)

Summary

Introduction

There has been an urgent demand for temperature and pressure measurements in the high-temperature and high-gas-pressure environments of turbine engines, highspeed aircraft, and other aerospace applications. The existing electrical sensors cannot operate in extreme environments. Optical fiber sensors have the advantages of high temperature resistance, electromagnetic interference immunity, small volumes and passive sensing, making them suitable for measuring temperatures and gas pressures in some extreme environments. Fiber Bragg gratings (FBGs) were widely used for hybrid measurements of temperature and pressure. A FBG is fabricated by periodically changing the refractive index of the core with ultraviolet light and fiber-core doped Ge. a FBG cannot work over 300◦C for a long time [1]–[4].

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