Bragg grating temperature self-compensation pressure sensor on fiber cladding surface

Abstract

The invention discloses an optical fiber cladding surface Bragg grating temperature self-compensating pressure sensor, which comprises an optical fiber core and an optical fiber cladding coating the optical fiber core, and is characterized in that: the front segment of the optical fiber core is provided with a long-period optical fiber grating, and the long-period optical fiber grating serves as an optical resonance coupler of the optical fiber core and the optical fiber cladding; the outer surface of the optical fiber cladding is provided with an optical fiber cladding surface Bragg grating at the position corresponding to the middle segment of an optical fiber, and the optical fiber cladding surface Bragg grating is composed of a plurality of linear grooves or a plurality of dotted grooves; the linear grooves or the dotted grooves are distributed periodically along the axial direction of the optical fiber; and the outer surface of the optical fiber cladding surface Bragg grating is provided with an elastic membrane for sensing external lateral pressure. The optical fiber cladding surface Bragg grating temperature self-compensating pressure sensor can determine magnitude of pressure and temperature of the external environment simultaneously, can achieve the temperature self-compensating function, and can be widely used in the fields of oil well pressure monitoring, gas / oil pipe pressure intensity monitoring, landslide early warning and the like.

Description

technical field [0001] The invention relates to an optical fiber sensor, in particular to a Bragg grating temperature self-compensating pressure sensor on the surface of an optical fiber cladding. Background technique [0002] In many building structures, gas / oil pipelines and security systems, the measurement of various pressures is very important and necessary. For example: monitoring of gas / liquid pressure in bridges, dams, high-rise buildings, traffic tunnels, gas / oil pipelines in construction projects, deep-water pressure detection for underwater oil exploration, etc. [0003] At present, the existing pressure sensors can be divided into three categories according to the measurement methods of various parameters and the physical properties of the measurement process: mechanical type, electrical measurement type, and optical type. Among them, the mechanical type can measure lower frequency and poorer precision, but it is relatively simple and convenient in field testing...

AI Technical Summary

Problems solved by technology

However, the FBG pressure sensor still has the influence of temperature cross effect in the application, so various additional temperature compensation methods are required to correct the pressure measurement. Generally, a pair of FBG combinations with different resonance wavelengths are used for temperature compensation. , which will increase the number and size of sensors; in addition, the pressure sensitivity of bare FBG is very small, so a special sensitization device is needed to increase the pressure sensitivity of bare FBG

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