Photon counting-based ultra-multipoint low-reflectivity fiber grating sensing system

Abstract

Ultra multi-point low reflectivity fiber grating sensing system based on photon counting, including semiconductor light source and its driving circuit, optical coupler and optical circulator, FBG sensing array, APD photodetector, PIN photodetector, photon counter and Computer; the APD light detector is used as the detection device of the sensing signal, and the PIN light detector is used as the detection device of the trigger signal. The computer controls the driving circuit of the light source to turn on the light source, and the light source outputs pulsed light, which is divided into two paths by the optical coupler , one way to the FBG sensor array, and the other way to the PIN photodetector; the trigger light controls the gating circuit and photon counter after photoelectric conversion, and when the FBG sensor array reflects back the signal, the gating circuit and photon counter are turned on, so that the APD light detection The device works in Geiger mode, counts with a counter and sends it to the computer for data processing, and calculates the strain of the FBG. The invention eliminates the influence of most of the thermal noise of the detector, greatly improves the signal-to-noise ratio of the measurement result, and can detect extremely weak sensing signals.

Description

technical field [0001] The invention belongs to the technical field of optical fiber grating sensing, and relates to a photon counting-based ultra-multipoint low reflectivity optical fiber grating sensing system. Background technique [0002] The rapid development of the modern economy and society has brought good development opportunities for the construction industry and large-scale projects, but the health and safety monitoring issues that follow (such as large dams, bridges, spacecraft, high-speed railways, ships, nuclear power plants, etc.) structure) is becoming increasingly apparent. Moreover, our country is a country with frequent disasters, such as the Zhouqu mudslide in 2010 and the bridge collapse of the Baocheng Railway. If early warning can be given, the loss of life and property of the people can be avoided. All of these can be monitored by a large number of sensors. [0003] Fiber Bragg grating sensors can detect various physical quantities such as temperatu...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a photon-counting-based ultra-multi-point low-reflectivity fiber grating sensing system to solve the problem in the prior art that it is difficult to detect weak sensing signals

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