Optical fiber Fabry-Perot pressure sensor and fabrication method thereof

Abstract

The invention relates to a novel optical fiber Fabry-Perot pressure sensor and a fabrication method thereof. The optical fiber Fabry-Perot pressure sensor is used for detecting the relative pressure and absolute pressure of liquid and gas as well as sound wave signals, ultrasonic wave signals and the like. The structure of the optical fiber Fabry-Perot pressure sensor mainly comprises an optical fiber, an elastic diaphragm, a sensor body and a miniature spring. Two methods and an alternative method can be adopted to form a Fabry-Perot cavity and fabricate the sensor. The elastic diaphragm and the sensing optical fiber are tightly contacted in a plane-sphere point contact manner; when the outside pressure is changed to cause the deformation of the elastic diaphragm, the diaphragm can drive the optical fiber to axially move in the sensor body, so that the length of the Fabry-Perot cavity of the optical fiber is changed; after a broadband light source is connected, by scanning the spectrum of the light passing through the optical fiber Fabry-Perot pressure sensor or extracting low-coherence interference fringes, the change of the cavity length can be extracted, and thereby pressure information can be obtained. The structure can avoid the defect that the diaphragm of the conventional optical fiber Fabry-Perot pressure sensor cannot be over-deformed, and can obtain higher measurement precision.

Description

【Technical field】: [0001] The invention relates to the field of optical fiber pressure sensor, which can be used to detect the relative pressure and absolute pressure of liquid and gas, and can also be used to detect sound waves, ultrasonic signals and the like. 【Background technique】: [0002] Optical fiber Fabry-Perot pressure sensor is a kind of optical fiber pressure sensor. It usually consists of an optical fiber end face and a diaphragm end face to form a Fabry-Perot microresonator cavity. When the pressure acts on the diaphragm, the diaphragm will be deformed. , so that the length of the Fappel cavity changes, so as to realize the sensing. Some designs have been proposed in recent years, such as Don C.Abeysinghe in 2001 (DonC.Abeysinghe, Samhita Dasgupta, Joseph T.Boyd, Howard E.Jackson, A Novel MEMSpressure sensor fabricated on an optical fiber, IEEE Photonics Technology Letters, 2001 , 13(9):993-995) etched microcavities on the end faces of multimode optical fibers...

AI Technical Summary

Problems solved by technology

However, when the deformation of the silicon wafer as a pressure diaphragm is too large, the silicon wafer will not be able to maintain a plane, resulting in a large loss of light energy, which affects the performance of the Fabry-Perot cavity; , the ambient temperature has a great influence on the stability of the sensor

Therefore, in actual use, the Fabry-Perot cavity is limited to a small range, and the deformation of the silicon wafer is often not allowed to be too large, for example, it cannot be greater than 25% of the thickness

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