基于宽带声光调制的高保真相位敏感光时域反射计系统  

High Fidelity Phase-Sensitive Optical Time Domain Reflectometer System Based on Broadband Acousto-Optic Modulation

作　　者：雷艳阳 姜桃飞 马云宾 夏猛 汤晓惠 隋景林 杨芳 杜学新 董永康[1,2,4] Lei Yanyang;Jiang Taofei;Ma Yunbin;Xia Meng;Tang Xiaohui;Sui Jinglin;Yang Fang;Du Xuexin;Dong Yongkang(Elite Engineers School,Harbin Institute of Technology,Harbin 150001,Heilongjiang,China;Zhengzhou Research Institute,Harbin Institute of Technology,Zhengzhou 450018,Henan,China;Pipe China Institute of Science and Technology,Langfang 065000,Hebei,China;School of Astronautics,Harbin Institute of Technology,Harbin 150001,Heilongjiang,China)

机构地区：[1]哈尔滨工业大学卓越工程师学院,黑龙江哈尔滨150001 [2]哈尔滨工业大学郑州研究院,河南郑州450018 [3]国家管网集团科学技术研究院,河北廊坊065000 [4]哈尔滨工业大学航天学院,黑龙江哈尔滨150001

出　　处：《光学学报》2024年第1期316-324,共9页Acta Optica Sinica

基　　金：跨地域复杂油气管网安全高效运行状态监测传感系统及应用(2022YFB3207602);国家自然科学基金(62205088)。

摘　　要：相位敏感光时域反射计(Ф-OTDR)系统通常用于振动监测中,具有响应速度快和检测灵敏度高的优势,但受相干衰落效应的影响,导致振幅较低位置提取的振动信号相位信息失真。为此,本文提出一种基于宽带声光调制的高保真Ф-OTDR传感方案,实现对振动信号相位信息的高保真提取。该方案具有调制结构简单紧凑、相位延迟控制精确、频率分量灵活可控、不牺牲响应带宽和空间分辨率等优点。在验证实验中,灵活调制脉宽为100 ns,且同时将包含三个非等间距频率的多频探测光脉冲注入2 km的传感光纤,并以幅值评估的方式对多频拍频信号进行复用。结果表明,该方案中相干衰落的概率从17.541%降低到0.045%,并实现了对模拟振动信号相位信息的高保真重构。Objective The phase-sensitive optical time domain reflectometer(Φ-OTDR)system can quantitatively characterize the vibration events along the sensing fiber by extracting the phase information of Rayleigh scattered light,which features a fast response up to milliseconds or sub-milliseconds and a detection sensitivity of nanostrains.Φ-OTDR has been widely used in sensing scenarios such as seismic wave monitoring,perimeter intrusion monitoring,and pipeline leak monitoring.Due to the interference fading effect in theΦ-OTDR system,the phase information extracted at the lower signal amplitude is distorted,which results in the incorrect response of the intensity and frequency of the vibration event.Then,it introduces frequent false alarms in practical engineering applications.Over the past decade and beyond,tremendous efforts have been devoted to addressing this issue,typically including the utility of special optical fibers(i.e.,seven-core fiber and periodic ultra-weak Bragg grating array),complex demodulation algorithm(i.e.,phase-shifted double pulse method and tracking algorithm),and multi-frequency pulse modulation[i.e.,phase-shifted double pulse method and multi-branch acoustic-optic modulator(AOM)modulation].From an applicative point of view,a simple multi-frequency pulse modulationΦ-OTDR system for suppressing the interference fading effect,which features flexible controlling of the frequency component of the probe optical pulse without sacrificing the response bandwidth and spatial resolution,is still a research gap to date.Methods In this paper,for the first time(to the best of our knowledge),an AOM for generating multi-frequency probe light is employed in theΦ-OTDR system.The modulation frequency interval and number can be flexibly controlled by an arbitrary waveform generator(AWG)within the operating bandwidth of the broadband AOM.Subsequently,the continuous multi-frequency probe light is modulated into pulsed light through a general AOM.The multi-frequency beat signals can effectively suppress the inhere

关 键 词：相位敏感光时域反射计 相干衰落效应 相位信息 多频脉冲调制 

分 类 号：TN247[电子电信—物理电子学]