干涉型分布式光纤振动传感周界安防监测系统研究

针对长距离、大范围周界安防的需求,设计了复合干涉型分布式光纤振动传感周界安防系统。研究了光纤干涉方式实现振动传感的机理,为克服传统干涉结构两路传感光纤需等长且相互隔离的问题,提出采用Sagnac与Mach-Zehnder复合光路结构,通过测量干涉光强的变化还原调制光信号中的振动信号,实现对入侵行为的感知。实验结果证明,本系统的频率响应范围在100 Hz~20 kHz,可良好还原外界振动信号,在20 km的测试距离内,可灵敏感知外界扰动。

Research on Interferometric Distributed Optical Fiber Perimeter Security Monitoring System

In order to meet the needs of long distance and wide range perimeter security,a composite interference distributed fiber optic vibration sensor perimeter security system is designed.The mechanism of realizing vibration sensing by optical fiber interferometry is studied.In order to overcome the problem that two sensing fibers of traditional interference structure need equal length and are isolated from each other,a Sagnac and Mach-Zehnder composite optical path structure is proposed to restore the vibration signal modulated in the phase of light by measuring the change of interference light intensity,so as to realize the perception of intrusion behavior.Experimental results show that the frequency response range of the system is 100 Hz~20 kHz,which can well restore the external vibration signal,and can sensitively sense the external disturbance within the test distance of 20 km.