分布式传感光纤应变和温度同时标定方法

Simultaneous Calibration Method for Strain and Temperature of Distributed Sensing Optical Fibers

为了实现分布式传感光纤应变和温度响应系数的快速准确标定,提出了应变和温度同时标定法.利用恒温装置控制传感光纤和金属管的温度,利用金属管的线性热膨胀对缠绕其上的分布式传感光纤施加应变,通过恒温装置中的松弛传感光纤补偿金属管上传感光纤的温度,共同实现应变和温度的同时、快速、准确标定.利用恒温水浴和不锈钢管进行了单模裸纤布里渊频移应变和温度响应系数的标定实验,应变标定跨度620με,温度标定范围35~75℃,得到单模裸纤布里渊频移的应变和温度响应系数分别为0.048 MHz/με和1.06 MHz/℃.结果表明该方法可用于小直径分布式传感光纤的应变和温度同时标定.

In order to realize the quick and accurate calibration for strain and temperature response coefficients of distributed sensing optical fibers, a novel method for simultaneous calibration of strain and temperature was proposed. The temperature of sensing fiber and metal tube was controlled by the thermostat. The strain of optical fiber twined around the metal tube was controlled by the linear thermal expansion of the metal tube. The temperature change of optical fiber around the metal tube was compensated by the loose fiber in the same thermostat. So that the simultaneous, quick and accurate calibration of strain and temperature can be realized. The strain and temperature response coefficients of Brillouin frequency shift of bare single-mode fiber were calibrated using a thermostatic waterbath and a stainless steel tube. The calibration span of strain was 620 με, the calibration range of temperature was 35-75℃. The strain and temperature response coefficients of Brillouin frequency shift of bare single- mode fiber were 0. 048 MHz/με and 1. 06 MHz/℃ respectively. Experiment results indicate that the method can be used to calibrate the strain and temperature of minor diameter distributed sensing fiber simultanously.