Optical fiber F-P cavity stress relief pressure sensor

Abstract

The invention discloses an optical fiber F-P cavity stress relief pressure sensor. The optical fiber F-P cavity stress relief pressure sensor comprises an upper ferrule provided with an F-P cavity, a lower ferrule integrally and fixedly connected with the upper ferrule axially, an optical fiber inserted into the lower ferrule, and a pressure diaphragm covering the port of the F-P cavity, wherein the pressure diaphragm and the upper ferrule are connected together to form the F-P cavity; a stress relief structure is designed in a bonding area and a pressure sensing area of the pressure diaphragm; the stress relief structure is composed of stress relief holes distributed in the bonding area and the pressure sensing area; and stress generated by thermal mismatch between the pressure diaphragm and the upper ferrule is released through the differently-shaped through holes. The stress relief through holes in the bonding area can relieve the stress generated by the thermal mismatch between the pressure diaphragm and the upper ferrule, and the temperature sensitivity of the F-P cavity pressure sensor can be well eliminated. The optical fiber F-P cavity stress relief pressure sensor of the invention has the advantages of simple structure, convenient manufacture, low cost and high precision.

Description

technical field [0001] The present invention relates to an F-P cavity pressure sensor widely used in different fields for measuring physical quantities such as stress, strain, pressure, temperature, etc., in particular to an optical fiber F-P cavity pressure sensor with a stress relief structure. Background technique [0002] The sensitive part of the optical fiber F-P cavity pressure sensor is the optical fiber F-P cavity. When the light enters the optical fiber F-P cavity, it will be reflected multiple times between the two reflective end faces to form a multi-beam interference spectrum. When the pressure test is carried out, the change of the external pressure will cause the change of the fiber F-P cavity length, which will cause the change of the multi-beam interference spectrum, and the pressure value can be calculated by using the external demodulation equipment. The optical fiber F-P cavity pressure sensor is developed along with the development of optical fiber commu...

AI Technical Summary

Problems solved by technology

[0007] 1. The pressure-sensitive diaphragm and the glass groove belong to different materials. Due to the difference in their thermal expansion coefficients, there is a large stress at the bond between the pressure-sensitive diaphragm and the glass groove, which makes the temperature drift coefficient of the optical fiber F-P cavity pressure sensor Large, poor linearity;

[0008] 2. Due to the thermal stress mismatch between the pressure-sensitive diaphragm and the glass groove, the pressure-sensitive diaphragm will produce additional deformation with temperature changes, so that the repeatability of the optical fiber F-P cavity pressure sensor will decrease, and the time drift will increase, further reducing F-P Accuracy of the pressure sensor

[0009] At present, the difficult problem that plagues the comprehensive performance of the optical fiber F-P pressure sensor is that the temperature effect causes additional stress inside the optical fiber F-P cavity pressure sensor, resulting in a decrease in sensor accuracy and reliability.

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