Super multipoint low reflectivity fiber Bragg grating sensing system based on photon counting

Abstract

A super multipoint low reflectivity fiber Bragg grating sensing system based on photon counting comprise a semiconductor light source and a drive circuit of the semiconductor light source, an optical coupler and an optical circulator, a fiber Bragg grating (FBG) sensing array, an avalanche photodiode (APD) optical detector, a photodiode (PIN) optical detector, an photon counter and a computer, wherein the APD optical detector serves as a detecting device for sending signals, the PIN optical detector serves as a detecting device for trigger signals, the computer controls the drive circuit of the light source to turn on the light source, the light source outputs pulsed light which is divided into two paths, one path reaches the FBG sending array, and the other path reaches the PIN optical detector; triggering light is through light-to-current conversion and then controls a door control circuit and the photon counter, when the FBG sensing array reflects the signals, the door control circuit and the photon counter are turned on, the APD optical detector is enabled to work in a Geiger mode, the photon counter is used for counting and a counting result is sent to the computer to be through data process, and strain size of FBG is figured out. The super multipoint low reflectivity fiber Bragg grating sensing system based on the photon counting is capable of eliminating most thermal noise of the detectors, greatly improving a signal to noise ratio of measuring results and detecting 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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