基于光纤移频延时环的Φ-OTDR信号衰落抑制方法  

Fading suppression method of Φ-OTDR signal based on optical fiber frequency-shifted delay loop

作　　者：王宇 王俊虹 梁斌 刘昕 靳宝全 Wang Yu;Wang Junhong;Liang Bin;Liu Xin;Jin Baoquan(Key Laboratory of Advanced Transducers and Intelligent Control System of Ministry of Education and Shanxi Province,Taiyuan University of Technology,Taiyuan 030024,China;Shanxi Transportation Technology Research&Development Co.,Ltd.,Taiyuan 030600,China)

机构地区：[1]太原理工大学新型传感器与智能控制教育部与山西省重点实验室,太原030024 [2]山西省交通科技研发有限公司,太原030600

出　　处：《仪器仪表学报》2022年第11期23-30,共8页Chinese Journal of Scientific Instrument

基　　金：国家自然科学基金(62175175);山西省基础研究计划(202103021222010);山西省基础研究计划(20210302124599);山西省专利转化专项计划项目(202202050);山西省重点研发计划项目(202102130501021);山西省科技创新人才团队专项(201805D131003)资助。

摘　　要：多频探测是相位敏感光时域反射仪(Φ-OTDR)光纤传感系统中干涉衰落抑制的重要手段,但存在多频率生成造成结构复杂的问题。提出了一种基于光纤移频延时环的多频脉冲产生方法,设计了包含移频、放大、延时、滤波、隔离等环节的光纤环结构,使用简单结构实现了多频探测脉冲的产生与复用。并分别采用脉冲延时补偿算法与旋转矢量求和算法对瑞利后向散射拍频信号实现了数据对齐与数据聚合。实验结果表明,传感系统通过生成包含6个频率分量的多频探测脉冲,可在10.33 km的传感光纤上将衰落概率由26.43%优化至0.93%,并实现了信噪比为5.29 dB的振动信号准确定位,以及相关系数为0.997的振动信号线性解调,从而为Φ-OTDR系统在复杂环境下的振动信号抗衰落解调提供了新的解决方案。The multi-frequency detection is an important way of interference fading suppression in the optical fiber sensing system of Φ-OTDR. But, there is the problem of complex structure caused by multi-frequency generation. A multi-frequency pulse generation method based on the optical fiber frequency-shifted delay loop is proposed in this article. Optical fiber loop structure is designed with frequency shift, amplification, delay, filtering, isolation and other functions. The generation and multiplexing of multi-frequency detection pulses are realized by using this simple structure. The data alignment and data aggregation of Rayleigh backward scattering beat signal are realized by using the pulse delay compensation algorithm and rotated-vector-sum algorithm, respectively. The experimental results show that the sensing system can optimize the fading probability from 26.43% to 0.93% with the 10.33 km sensing fiber by the generation of multi-frequency detection pulses containing six frequency components, and achieve the accurate location of the vibration signal with a signal-to-noise ratio of 5.29 dB and the linear demodulation of the vibration signal with a correlation coefficient of 0.997. It provides a new solution of anti-fading demodulation of vibration signal for Φ-OTDR in complex environment.

关 键 词：光纤传感 相位敏感光时域反射仪 光纤移频延时环 干涉衰落抑制 

分 类 号：TH741[机械工程—光学工程] TN247[机械工程—仪器科学与技术]