相位敏感光时域反射计的高频振动检测  

High-Frequency Vibration Detection of Phase-Sensitive Optical Time-Domain Reflectometer

作　　者：宋牟平[1] 庄守望 王轶轩 Song Muping;Zhuang Shouwang;Wang Yixuan(College of Information Science and Engineering,Zhejiang University,Hangzhou,Zhejiang 310027,China)

机构地区：[1]浙江大学信息与电子工程学院,浙江杭州310027

出　　处：《中国激光》2020年第5期440-444,共5页Chinese Journal of Lasers

摘　　要：相位敏感光时域反射计(φ-OTDR)可以有效地检测光纤的振动信息,但受传感光纤长度的限制,可检测的振动频率范围一般在几百赫兹到几千赫兹之间。为了提高振动检测范围,组建了基于外差相干检测的φ-OTDR系统,采用I/Q解调方法获得传感光纤散射光信号的相位信息,对此相位信息在空间域与时域上相继进行差分相位解调,从而实现对光纤中高频振动信号的分布式检测。理论上分析了高频振动检测方案的可行性,并在实验中有效解调出了频率为500 kHz的振动信号,传感距离达到了23 km。The phase-sensitive optical time-domain reflectometer(φ-OTDR)can effectively detect the vibration information of fiber;however,the detectable vibration frequency range is generally between several hundred hertz and several kilohertz,limited by the length of the sensing fiber.To improve the vibration detection range,aφ-OTDR system that uses heterodyne coherent detection is built in this study.The phase information of the scattered optical signal of the sensing fiber is obtained using the I/Q demodulation method.Differential phase demodulation in the space and time domains is consecutively performed to achieve a distributed detection of high frequency vibration signals in the fiber.Furthermore,the feasibility of the proposed high-frequency vibration detection scheme is theoretically analyzed,and the vibration signal with a frequency of 500kHz is effectively demodulated in the experiment,obtaining a sensing distance of 23km.

关 键 词：光通信 相位敏感光时域反射计 高频振动检测 外差检测 相位解调 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]