喇曼散射的分布式光纤测温系统中,由于光纤色散效应,反斯托克斯光与斯托克斯光传播速度不同会引起采集信号错位,导致测量误差.本文提出了一种利用分段三次Hermite插值算法修正反斯托克斯信号,消除信号错位,降低系统测量误差的方法.该方法在1 km传感样机上进行了验证.未修正时,反斯托克斯信号与斯托克斯信号在光纤尾端错开1个点,导致升温峰前端出现－7.45%的误差,经过插值修正后,消除了信号错位,使系统的测量误差在±1.5%以内.

In the distributed Raman optical fiber temperature measurement system,Anti-Stokes light and Stokes light have different propagation speeds due to the fiber dispersion effect,this will cause mismatch of the acquisition signals,resulting in measurement error. A method was proposed to use the piecewise cubic Hermite interpolation algorithm to correct the Anti-Stokes signal,eliminating signal mismatch and reducing the system measurement error. The method is verified on our 1 km sensing prototype. Before correction,the Anti-Stokes signals have one point more than the Stokes signals,causing －7.45% error at front of the temperature peak. After interpolation correction,the signal mismatch is eliminated,resulting in the system measurement error within ±1.5%.