多频COTDR系统的相位解调优化方法  

Phase Demodulation Optimization Method for Multi-Frequency COTDR System

作　　者：谢浪 吴明松 王粤晖 杨子逸 饶云江 吴宇 Xie Lang;Wu Mingsong;Wang Yuehui;Yang Ziyi;Rao Yunjiang;Wu Yu(Key Laboratory of Optical Fiber Sensing and Communications(Education Ministry of China),School of Information and Communication Engineering,University of Electronic Science and Technology of China,Chengdu 611731,Sichuan,China)

机构地区：[1]电子科技大学信息与通信工程学院光纤传感与通信教育部重点实验室,四川成都611731

出　　处：《光学学报》2024年第1期325-332,共8页Acta Optica Sinica

基　　金：重点联合基金项目(U21A20453)。

摘　　要：提出一种基于多频优化分集(MFOD)算法的相位解调技术,搭建了环移多频相干光时域反射(MF-COTDR)系统,实验探究了MFOD算法对信号解调性能的提升效果。结果表明,MFOD算法不仅能够较好地还原相位信息,相较于传统的相位解调算法有超过9 dB的平均信噪比(SNR)提升,实现了33.3 pε/Hz1/2的最小应变分辨率。此外,通过实验验证了基于MFOD算法的MF-COTDR系统对不同频率振动信号的响应性能,实验结果说明该系统具有良好的线性响应能力。Objective Optical fiber distributed acoustic sensing(DAS)system is a type of acoustic sensor built upon optical fibers and optoelectronic technology.It primarily utilizes optical coherence detection technology to convert acoustic vibration signals into optical signals,which are then transmitted through optical fibers to a signal processing system,thereby obtaining valuable acoustic wave data.They possess advantages such as high sensitivity,wide dynamic range,resistance to electromagnetic interference,structural flexibility,scalability into large-scale arrays,and suitability for extremely harsh conditions.Consequently,since their advent,driven by significant military and civilian applications,they have rapidly developed into an important direction in modern optical sensing and acoustic sensing technology.In recent years,DAS has been widely applied in fields such as oil and gas pipeline monitoring,national defense security surveillance,power cable monitoring,and structural health monitoring of large-scale infrastructure.With the expanding applications of DAS,there is a growing need for acoustic measurement solutions with higher sensitivity and reduced noise floors.To meet these demands,researchers have employed techniques to reduce system phase noise and suppress the fading phenomenon in the context of coherent optical time-domain reflectometry(COTDR)systems.The traditional COTDR systems struggle to achieve ideal signal demodulation due to the presence of signal fading phenomena.We propose a phase demodulation technique based on the multi-frequency optimized diversity(MFOD)algorithm.Methods This experiment employed a multi-frequency coherent optical time-domain reflectometry(MF-COTDR)system based on the frequency-shifted loop structure.Firstly,a detailed description of the phase demodulation method in the traditional COTDR systems was provided.This was followed by the utilization of multiple matching bandpass filters to separate detection pulses of different frequencies,achieving phase demodulation in the MF-COTDR

关 键 词：光纤光学 分布式光纤传感 相位敏感光时域反射仪 相位解调 

分 类 号：TP212.9[自动化与计算机技术—检测技术与自动化装置]