基于BOTDA的光纤分布式传感温度补偿

布里渊光时域分析(Brillouin Optical Time Domain Analysis, BOTDA) 利用了布里渊受激放大特性,在测量精度和空间分辨率等方面有独特的优势。在应用基于BOTDA的分布式光纤传感技术对结构应变进行监测时,存在布里渊频移对应变和温度交叉敏感的问题。为了消除温度对应变监测的影响,基于BOTDA原理提出了一种温度补偿方法。结果表明该方法可通过附着成一体的应变和温度传感光纤的换算得到消除温度影响后的应变,无需得到待测物温度场,布设安装和数据处理均较方便,温度信息同步性和环境适应性较佳,且成本低廉,与现有温度补偿方法相比具有显著优势。通过对比室内水浴试验和某排水泵站现场试验的结果,可知基于BOTDA的光纤分布式传感温度补偿方法是有效的。

Temperature Compensation for BOTDA-based Distributed Fiber Optic Sensors

Brillouin optical time domain analysis (BOTDA) has unique advantages in measuring precision and spatial resolution due to stimulated amplification of Brillouin scattering. When BOTDA-based distributed fiber optic sensors are applied to strain monitoring of structures, the Brillouin frequency shift is sensitive to both strain and temperature. To eliminate the influence of temperature on strain, a temperature compensation method based on BOTDA is herein proposed. The temperature-compensated structural strain can be obtained from the strain recorded from the integrated cable including optical fibers of both temperature sensing and strain sensing without involving the temperature. The installation and data processing are convenient to be conducted with favorable information synchronizing and environmental suitability as well as low cost. The proposed method has significant advantages in comparison with existing temperature compensation methods and is validated by indoor water bath tests and field tests for a drainage pumping station during construction.