Sensing prob as well as fiber interfering device and method for inhibiting polarization-induced fading

Abstract

The invention provides a sensing probe as well as a fiber interfering device and method for inhibiting polarization-induced fading. The sensing probe comprises a sealing cavity, wherein a sensor diaphragm, a first circulator and a first Faraday rotating mirror are arranged in the sealing cavity; the sensor diaphragm is used for sensing an external sound wave vibration signal; the sensor diaphragmis further provided with a boss for improving the sensitivity of the sensing probe; the sensor diaphragm is provided with a sensing fiber ring; one end of the sensing fiber ring is connected with an input fiber, and the other end is connected with the first port of the first circulator; the second port of the first circulator is connected with the first Faraday rotating mirror; and the third portof the first circulator is used for outputting detection light for sensing the change of the external sound wave vibration signal.

Description

technical field [0001] The disclosure belongs to the field of optical fiber interference devices, and in particular relates to a sensing probe, an optical fiber interference device and a method for suppressing polarization fading. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art. [0003] Optical fiber interference is widely used in the measurement of various external signals, such as vibration, temperature, stress, etc. Its principle is that the phase change of the interfering light is caused by the change of the external physical quantity, and the external physical quantity is realized by detecting the phase change of the interfering light. Measurement. Therefore, the acquisition of stable interference light becomes the key to realize the accurate measurement of external physical quantities. [0004] The Mach-Zehnder fiber interference structure...

AI Technical Summary

Problems solved by technology

[0004] The Mach-Zehnder fiber interference structure is widely used in vibration signal measurement, but when the fiber is disturbed by the outside world, due to the birefringence effect of the fiber, the polarization state in the ordinary single-mode fiber will change randomly, resulting in random detection signals. Fading, especially when the polarization states of the light in the two arms of the fiber optic interferometer are orthogonal, the interference signal output by the interferometer is zero, so polarization-induced signal fading has become a serious problem affecting signal measurement of interferometric fiber optic sensors

The inventor found that at present, researchers generally use a polarization controller on a single-mode fiber to suppress polarization fading. Although it has certain effects, it increases the system cost and has obvious hysteresis

Zhou Xiaodong from Zhejiang University and others conducted theoretical analysis and simulation research on the elimination of polarization-induced signal fading of interferometric optical fiber sensors by diversity detection technology, but three detectors are required to detect at the same time, and the system is cumbersome

In addition, there is polarization state modulation technology, but this method will significantly reduce the system signal-to-noise ratio

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