Micro-fiber extrinsic-type Michelson sound pressure sensor with common optical path structure

Abstract

The invention belongs to the optical fiber sensing technology field and especially relates to a micro-fiber extrinsic-type Michelson sound pressure sensor with a common optical path structure. The sensor is formed by a sound pressure sensitive diaphragm, a diaphragm support structure, a sensor pedestal, a first high reflecting film, a second high reflecting film, a glass casing pipe, an optical fiber collimating lens, an optical fiber sleeve, and a single mode fiber. The sound pressure sensitive diaphragm is fixed to the diaphragm support structure. The diaphragm support structure is fixed tothe upper surface of the sensor pedestal. The external diameters of the diaphragm support structure and the sensor pedestal are the same. The internal middle areas of the diaphragm support structure and the sensor pedestal have circle through holes. The diameter of the through hole of the diaphragm support structure is greater than the diameter of the through hole of the sensor pedestal. Through adopting the common optical path structure, sensor signal fading caused by polarization fading can be avoided without using a Faraday polariscope so that the stability of a detection result is ensured,and good processing consistency is possessed.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, and in particular relates to a miniature optical fiber extrinsic Michelson acceleration sensor with a common optical path structure. Background technique [0002] Diaphragm fiber optic acoustic pressure sensor has the advantages of small size, light weight, high sensitivity, and no electrical interference. It has achieved rapid development in recent years and has been widely used in ultrasonic testing, underwater acoustic detection, aerospace and other fields. At present, the common membrane fiber optic acoustic pressure sensors are usually based on the Fabry-Perot interference structure, and its structural feature is to use the end face of the optical fiber and the inner surface of the membrane to form a Fabry-Perot cavity. The main problem of this structure is that the distance between the end face of the optical fiber and the inner surface of the diaphragm is not easy to control,...

AI Technical Summary

Problems solved by technology

However, in this structure, it is difficult to control the distance between the fiber collimator and the diaphragm, which makes it difficult to ensure the consistency of the optical path difference between the two optical paths of the Michelson interferometer; and the structure of the split optical path cannot prevent polarization fading. Impact

[0004] In summary, the prior art has the problem that the distance between the fiber collimator and the diaphragm is not easy to control

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