An ultra-weak fiber grating perimeter security system

Abstract

The invention discloses an ultra-weak optical fiber grating perimeter security system and method, wherein the system includes: a detection optical cable, which is armored by optical fibers with a large number of ultra-weak grating arrays to form a micro-vibration optical cable; an inquiry unit is connected with the detection optical cable. It is used to separate and demodulate the reflection signal of the target grating in the array; the control unit is connected with the query unit, and is used to generate a pulse control signal and extract the wavelength demodulation signal synchronously, and determine and locate the intrusion behavior through signal processing and pattern recognition. The invention solves the multiplexing problem of multiple gratings in the traditional perimeter security system, allows the wavelength change of the grating caused by the local force when the grating is cabled and laid, the preparation and laying of the optical cable are simple, and the perimeter security system has high sensitivity and high sensitivity through optimized control. With the advantages of fast response, accurate positioning, and compatibility with perimeter security and temperature sensing, it has important application prospects in the field of perimeter security.

Description

technical field [0001] The invention relates to the technical field of optical fiber perimeter security, in particular to an ultra-weak fiber grating perimeter security system. Background technique [0002] Optical fiber perimeter security uses optical fiber as the sensing medium and signal transmission channel, which has the advantages of passive, anti-electromagnetic interference, and high sensitivity, and is convenient for long-distance deployment. The perimeter security field has a wide range of needs, [0003] In the mid-1990s, developed countries took the lead in applying optical fiber sensing technology to the perimeter security field. At present, the world that can master this technology and put it into use is mainly concentrated in a few countries such as Europe and the United States, such as the United Kingdom, the United States, Israel, Australia, etc., and mostly adopts the distributed sensing technology based on the principle of optical interference; The field...

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Problems solved by technology

The document "Wang Y M, Gong J M, Wang D Y, etal.A large Serial time-division multiplexed fiber Bragg grating sensornetwork[J].J.Lightw.Technol.,2012,30:2751-2756." proposed a laser wavelength The scanning time-domain query (WSTDM) method, due to the limitation of the wavelength conversion speed of the laser light source, takes tens of seconds for a query, and it is difficult to detect dynamic signals such as vibration; Sensing system and its query method") Although a fast query method for large-scale ultra-weak grating arrays based on CCD demodulation was proposed, it was mainly aimed at the monitoring of static quantities (such as temperature) and did not involve vibration signals in large-scale grating arrays. The dynamic detection of the perimeter security system does not consider the intrusion event identification, response time, positioning accuracy, multi-point monitoring and other issues, so it is difficult to meet the requirements of the fiber optic perimeter security technology

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