基于喇曼散射的分布式光纤温度传感器的温度修正

Temperature Calibration of Distributed Optical Fiber Temperature Sensor Based on Raman Scattering

结合基于喇曼散射的分布式光纤温度传感器的基本原理及温度解调过程,研究和分析了温度测量产生误差的主要原因.采用拟合修正的方法来解决斯托克斯光和反斯托克斯光传输损耗差异以及光纤弯曲、应力等附加损耗对系统的影响;采集光纤起始端同一位置3个不同温度的信号值求解非线性方程组,实现了对探测器暗电流引起的测量误差的修正.实验结果表明:经过修正的传感器在900m位置的温度测量误差平均值从8.0℃降到0.37℃,整条光纤的温度测量误差平均值≤±0.6℃.

The main causes of the temperature measurement error of Raman distributed optical fiber temperature sensor was researched and discussed based upon the Raman scatting principle and temperature demodulation algorithm. A method to address the effects caused by the attenuation differences between Stokes and anti-Stokes light, additional attenaution of fiber bending, stress and environment changes was proposed. Furthermore, the measurement error caused by dark current produced by the detector was also reduced by using nonlinear equations with three different temperature signals acquired along the same-fiber section location. The experimental results demonstrate that the aritmatic mean error of calibrated system has reduced from 8.0 ℃ to 0.37℃ with the fiber location found at 900 m. Overall, a temperature arithmatic mean error better than 0.6℃ is achieved.