基于BOTDR的多模光纤温度传感  

Multimode fiber temperature sensing based on BOTDR

作　　者：范海军 李永倩[1,2,3] 张立欣 刘紫娟[1,2,3] 王少康 刘艳蕊 FAN Haijun;LI Yongqian;ZHANG Lixin;LIU Zijuan;WANG Shaokang;LIU Yanrui(Department of Electronic and Communication Engineering,North China Electric Power University,Baoding 071003,China;Hebei Key Laboratory of Power Internet of Things Technology,North China Electric Power University,Baoding 071003,China;Baoding Key Laboratory of Optical fiber sensing and optical communication Technology,North China Electric Power University,Baoding 071003,China)

机构地区：[1]华北电力大学电子与通信工程系,河北保定071003 [2]华北电力大学河北省电力物联网技术重点实验室,河北保定071003 [3]华北电力大学保定市光纤传感与光通信技术重点实验室,河北保定071003

出　　处：《激光杂志》2022年第1期74-80,共7页Laser Journal

基　　金：国家自然科学基金(No.61775057、51607066);河北省自然科学基金(No.F2019502112、E2019502177);中央高校基本科研业务费专项基金(No.2019MS086)资助。

摘　　要：针对多模光纤存在的模式耦合和布里渊增益谱展宽限制传感精度的提高等问题,提出利用单模光纤对多模光纤中散射信号的高阶模进行过滤实现多模光纤分布式温度传感精度的提高。分析了多模光纤的布里渊散射与温度传感原理,搭建单模光纤滤模的移频本地外差布里渊光时域反射(BOTDR)系统,测量并比较了两种多模光纤的温度传感特性。结果表明:在单模光纤过滤高阶模的BOTDR系统中,阶跃折射率和渐变折射率多模光纤的布里渊频移的温度系数分别为(0.884±0.013)MHz/℃、(1.104±0.013)MHz/℃,温度测量精度分别为1.249℃、1.071℃;且利用单模光纤过滤散射信号中的高阶模可有效减小布里渊散射谱宽,75℃时分别为58.12 MHz、72.14 MHz,可有效提高多模光纤分布式温度传感精度。In view of the problems of mode coupling and Brillouin gain spectrum broadening in multimode fibers that limit the improvement of sensing accuracy, it is proposed to use single mode fiber to filter the high-order modes of scattering signals in multimode fiber to improve the distributed temperature sensing accuracy of multimode fibers. The Brillouin scattering and temperature sensing principle of multimode fiber were analyzed, and a frequency-shifted local heterodyne Brillouin optical time domain reflectometry(BOTDR) system with single mode fiber filtering modes was built to measure and compare the temperature sensing characteristics of two multimode fibers. The results show that in the BOTDR system with single mode fiber filtering high-order modes, the Brillouin frequency shift temperature coefficients of step-index and graded-index multimode fibers are( 0.884 ± 0.013) MHz/℃ and( 1.104 ± 0.013) MHz/℃, respectively, and the temperature measurement accuracy are 1.249 ℃ and 1.071 ℃, respectively. Single mode fiber filters the higher-order modes in the scattering signal can effectively reduce the Brillouin scattering spectrum widths, 58.12 MHz and 72.14 MHz at 75 ℃, respectively, which can effectively improve the distributed temperature sensing accuracy of multimode fiber.

关 键 词：多模光纤 温度传感 布里渊频移 单模光纤 模式截止 

分 类 号：TN253[电子电信—物理电子学]