Fabry-Perotw fiber-optic pressure sensor and manufacture method therefor

Abstract

This invention discloses one Fabry-Perot fiber pressure sensor, which comprises single silicon slice, glass round tube, fiber flange disc and fiber plug and is characterized by the following: the single silicon slice and glass round tube one end are connected through anode keys; other end of round tube is added to fiber flange disc tank; the fiber plug is connected to flange disc with ceramics needle and silicon slice form the chamber. This invention also discloses one method for it, which comprises the following steps: putting the cut glass tube and silicon slice onto key furnace; the glass tube outer wall is coasted with epoxy resin to flange concave tank; connecting the fiber plug into fiber flange disc to form the chamber.

Description

technical field [0001] The invention relates to a Fabry-Perot type optical fiber pressure sensor, in particular to a Fabry-Perot type optical fiber pressure sensor which uses a tunable laser for signal access and uses the wavelength change of the reflection spectrum to complete signal demodulation and its production method. Background technique [0002] Existing Fabry-Perot optical fiber sensors are mainly used to measure strain, such as extrinsic Fabry-Perot interferometers. It is composed of two cut fiber end faces placed in a quartz capillary and an air gap in the middle to form a resonant cavity. Such sensors can only measure the strain of an object and not the pressure. Figure 1 is its basic structure. [0003] Recently, Fabry-Perot type fiber optic sensors for measuring direct pressure have appeared. Figure 2 is a typical structure of it. A thin sheet of silicon covers the glass etched with a shallow cylindrical cavity, and the air cavity between the silicon and t...

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Problems solved by technology

However, this design also has the following disadvantages: first, the system uses the light intensity demodulation method, and the fluctuation of the light source has a great influence on the solution of the cavity length; second, glass and silicon wafers can also be formed as independent FP cavities Interference signals, and these signals carry useless information, interfere with the useful interference signal formed by the air cavity, and bring difficulties to signal demodulation; third, the size of the air cavity is very small, generally only a few microns, and the deflection of the silicon wafer It is also very small, but in the application, the deflection of the silicon wafer caused by vibration is comparable to the deflection caused by pressure, which also makes demodulation very difficult, and the repeatability of the sensor is also impossible to talk about; finally, the optical fiber is required to be aligned with the cavity, And there is no special alignment structure in the design, and there is no way to ensure that the fiber and the glass are kept perpendicular

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