F-P pressure sensor with compound dielectric film

Abstract

The invention discloses an F-P pressure sensor with a compound dielectric film. The F-P pressure sensor comprises an upper insertion core provided with an F-P resonant cavity, a lower insertion core fixedly connected with the upper insertion core as a whole in the axial direction, an optical fiber inserted into the lower insertion core, and a pressure-sensitive diaphragm covered onto the port of the F-P resonant cavity. At least one layer of the compound dielectric film grows on the back surface of the pressure-sensitive diaphragm and on a silicon wafer at the bottom of a groove inside the F-P resonant cavity. The compound dielectric film is a multi-layer film comprising at least one combination of a SiO2 / Ta2O5 film, a Si3N4 / Ta2O5 film or a SiO2 / Ta2O5 / Si3N4 film. The F-P pressure sensor is simple in structure, convenient and quick to manufacture, low in cost and relatively high in thermal stability. According to the invention, the compound dielectric film grows on the back surface of the pressure-sensitive diaphragm and the bottom surface of the groove of the upper insertion core. The pressure-sensitive diaphragm is connected with the upper insertion core to form the F-P resonant cavity that is matched with the reflectivity of the system. In this way, the compound dielectric film is good in thermal stability. At the same time, a reflectivity that meets system requirements can be obtained through combination based on design requirements.

Description

technical field [0001] The invention relates to an optical fiber F-P sensor widely used in the measurement of physical quantities such as temperature, strain, vibration and pressure, in particular to an F-P pressure sensor with a composite dielectric film. Background technique [0002] Optical fiber sensors use light as the information carrier and optical fiber as the signal transmission medium to sense and measure the measured parameters. It has good electrical insulation, strong anti-electromagnetic interference ability, and also has high temperature, high pressure, corrosion resistance characteristics, and can be used in harsh environments such as flammable and explosive. Optical fiber Fabry-Fabry (F-P) sensor is an important branch of optical fiber sensor. The sensitive part of the fiber optic F-P resonator pressure sensor is the fiber F-P resonator. When the light enters the fiber F-P cavity, it will be reflected multiple times between the two reflective end faces to f...

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Problems solved by technology

[0009] The purpose of the present invention is to provide a F-P pressure sensor with good thermal stability, high precision and good reliability, and a composite dielectric film to solve the problems of the current optical fiber F-P pressure sensor. Stability and reflectivity bring accuracy loss issues

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