Fiber air pressure sensing device based on multiple Fabry-Perot micro cavities

Abstract

The sensing device is characterized in that continuous discharging welding is performed on the single-mode fiber and the capillary tube in a welding mode that the discharging power of 45bit and the discharging time is 3000ms until one part of the capillary tube is expanded to be a hollow ball cavity; a capillary tube thin layer is formed at the welding place of the single-mode fiber and the capillary tube, so multiple Fabry-Parot cavities are formed; the circulator receives light from the broadband light source and transmits the light to the sensing head; the sensing head reflects the light back to the circulator and then is transmitted to the spectrum analyzer through the circulator, so a structure which is similar to a Fabry-Parot interferometer is formed; and wavelength drift quantity of reflection spectrum characteristic valleys is measured, so a value of a to-be-measured environmental parameter can be calculated. The sensing device is advantaged by small size and simple preparation and can be applied to measurement of air pressure and temperature.

Description

technical field [0001] The invention provides an optical fiber air pressure sensing device based on a plurality of Fabry-Perot microcavities, belonging to the technical field of optical fiber sensing. Background technique [0002] Atmospheric pressure is a very important parameter in the fields of meteorological telemetry, aircraft altitude determination, and field operations. Especially in recent years, with the revolutionary development of the field of UAVs, it is very urgent to monitor the height of UAVs quickly, in real time and accurately through remote measurement of atmospheric pressure. In the field of traditional atmospheric pressure measurement, force balance, resonant and piezoresistive air pressure sensing technologies are mostly used. In contrast, the fiber optic air pressure sensor has attracted more and more attention in the market due to its advantages of small size, anti-electromagnetic interference, high temperature resistance, strong chemical stability, a...

AI Technical Summary

Problems solved by technology

Relatively low gas pressure sensitivity of Fabry-Perot interferometer gas pressure sensor based on cavity length variation

After adding an ultra-thin diaphragm on the end face of the optical fiber, although this type of sensor can achieve an ultra-high sensitivity of up to 100nm / MPa, it only has a limited measurement range of tens of kPa

More importantly, the sensing head of optical fiber with ultra-thin diaphragm is less robust and difficult to maintain in hazardous environments

For gas pressure sensors based on Fabry-Perot interferometers based on changes in the refractive index in the cavity, although a larger range of measurement and better robustness can be achieved, the sensitivity is usually as low as tens of μm / MPa

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