相干光时域反射仪技术与应用  

Principle and Application of the C-OTDR

作　　者：刘中华 龚浩敏 吴岩 张益昕[3] LIU Zhong-hua;GONG Hao-min;WU Yan;ZHANG Yi-xin(Institute of Acoustics of the Chinese Academy of Sciences,Beijing 100190,China;FiberHome Telecommunication Technologies Co.,Ltd.,Wuhan 430073,China;Optical Communication Engineering Research Center,Nanjing University,Nanjing 210023,China)

机构地区：[1]中国科学院声学研究所,北京100190 [2]烽火通信科技股份有限公司,武汉430073 [3]南京大学光通信工程研究中心,南京210023

出　　处：《光通信研究》2022年第5期43-48,65,共7页Study on Optical Communications

基　　金：广东省重点领域研发计划资助项目(2020B0101080002)。

摘　　要：传统光时域反射仪(OTDR)技术是通过背向瑞利散射功率来进行光纤检测的,在带有光中继放大的传输线路中,大多采用掺铒光纤放大器(EDFA)来补偿信号光的损耗,延长信号光的传输距离,由于EDFA在对信号进行放大的同时会产生自发辐射噪声,噪声的不断累积会使OTDR测量的信噪比快速下降,导致无法测量。文章主要阐述了相干光时域反射仪(C-OTDR)的技术原理,通过相干探测方法把探测到的信号光功率集中到中频,通过对该频率信号进行带通滤波即可滤除大部分噪声,使其能穿过EDFA不断延伸探测距离。文章同时提出采用频移键控方式来消除海缆长距离传输多级中继器级联带来的光浪涌问题,以便将其应用于海缆长距离传输系统中。通过自研C-OTDR研制,在模拟海缆多跨传输系统中,C-OTDR技术的实际测试达到3000 km,完全具备实用条件。The traditional Optical Time Domain Reflectometry(OTDR)technology uses back Rayleigh scattering power for fiber detection.In transmission lines with optical amplifier,Erbium-Doped Fiber Amplifiers(EDFA)are mostly used to compensate for the loss of signal light and extend the transmission distance of the signal light.Since the EDFA amplifies the signal,it will generate spontaneous radiation noise,and the continuous accumulation of noise will rapidly decrease the signal-to-noise ratio measured by the OTDR.The paper mainly expounds the principle of Coherent Optical Time Domain Reflectometry(C-OTDR)technology.The detected signal optical power is concentrated to the intermediate frequency by the coherent detection method,and most of the noise can be filtered out by band-pass filtering the frequency signal.It can continuously extend the detection distance through the EDFA.We also propose to use the frequency shift keying method to eliminate the optical surge problem caused by the cascade of multi-stage repeaters in long-distance transmission of submarine cables.Through the development of self-developed coherent optical time domain reflectmeter,the actual test of C-OTDR technology in the simulated submarine cable multi-span transmission system has reached 3000 km,which fully meets practical conditions.

关 键 词：相干光时域反射仪 海缆 中继器 动态检测范围 声光调制器 频移键控 

分 类 号：TN929.11[电子电信—通信与信息系统]