基于光频域反射原理的分布式光纤应变传感解调算法改进

Improvement of Demodulation Algorithm for Distributed Optical Fiber Strain Sensing Based on Optical Frequency Domain Reflectometry

摘要:

利用光纤中的背向瑞利散射通过光频域反射原理实现整段光纤上的分布式应变测量。对应变解调算法进行了改进,采用二次互相关的方法实现了光纤的波长分辨率为5pm,空间分辨率为2cm。搭建了一套基于光频域反射原理的分布式光纤应变传感系统,对应变系数进行了标定,并实现了5m长光纤上的分布式应变测量,应变测量范围为50~500με,应变分辨率为4.2με。改进后的算法克服了传统算法中波长分辨率和空间分辨率相互制约的缺点,能在保证波长分辨率的前提下提高空间分辨率,对该应变传感技术的后续研究具有一定借鉴意义。

Abstract:

The distributed strain measurement on the whole fiber was realized by using the Rayleigh backscatter of optical fiber and the frequency domain reflectometry (OFDR).The demodulation algorithm was improved by using the method of double crosscorrelation, achieving a wavelength resolution of 5pm and a spatial resolution of 2cm. A distributed optical fiber strain sensing system was built and the strain coefficient was calibrated. The distributed strain measurement was performed on a 5m long fiber within the strain range of 50~500με, with a strain resolution of 4.2με. The improved algorithm, which has resolved the contradiction between wavelength resolution and spatial resolution, can improve the spatial resolution without sacrificing the wavelength resolution.