基于多频率综合鉴别φ-OTDR系统中干涉衰落假信号的相位解调技术  

Phase Demodulation Technology Using a Multi-Frequency Source for Discrimination of Interference-Fading Induced False Alarms in a φ-OTDR System

作　　者：周俊[1,2] 潘政清[1] 叶青[1] 蔡海文[1] 赵浩 瞿荣辉[1] 方祖捷[1] 

机构地区：[1]中国科学院上海光学精密机械研究所上海市全固态激光器与应用技术重点实验室,上海201800 [2]中国科学院大学,北京100049 [3]上海波汇通信科技有限公司,上海201203

出　　处：《中国激光》2013年第9期114-119,共6页Chinese Journal of Lasers

基　　金：国家863计划(2012AA041203);上海市科委高新技术处科级攻关项目(11DZ1140202);浦东新区科级发展基金(PKJ2012-D04)

摘　　要：对相位解调相位敏感光时域反射仪(φ-OTDR)系统中干涉衰落问题进行了研究。同一频率多次脉冲扫描显示出相似的衰落波形,而不同光频有不同的衰落波形。通过改进现有瑞利散射随机性和相干性物理模型,推出了瑞利散射系数是激光频率和有效折射率的函数,合理解释了上述实验现象。为了消除干涉衰落导致的系统误报问题,提出了一种基于多频率综合判决的方法,有效地区分并排除了误报,提高了整个φ-OTDR系统相位解调的准确性。The characteristics of interference fading in the phase-demodulated phase-sensitive optical time domain reflectometer（φ-OTDR） system are investigated. It is found that the fading waveforms have high similarity for different pulse scans, but obvious differences for different optical frequencies. An improved model for randomness and coherent noise of Rayleigh scattering is presented. It can be concluded that the composite Rayleigh scattering coefficient is a function of laser frequency and the index distribution, which could explain the experimental results reasonably. In order to eliminate the false alarms due to interference fading, a multi-frequency method is proposed, which can improve the accuracy of the phase demodulation in the φ-OTDR system.

关 键 词：传感器 相位敏感光时域反射仪 相干检测 衰落噪声 

分 类 号：TN212.14[电子电信—物理电子学]