基于BOTDR的传感光纤温度效应研究

Study on temperature effect of BOTDR-based optical fibers

为研究基于布里渊光时域反射测量(BOTDR)原理的分布式传感光纤在工程应用中的温度效应,对十种单模传感光纤在不同应力状态和布设方式下的温度系数进行了标定,并对光纤的护套、温度循环、应力状态、布设方式和附着介质等因素对光纤传感性能的影响进行了分析。试验分析结果表明:不同光纤外层护套材料的热膨胀率和热稳定性是影响传感光纤温度效应及其稳定性的主要原因。普通光纤频移-温度曲线大多为折线形,且在低温下(约40℃～-10℃)的温度系数大于高温时的温度系数;光纤的温度敏感性与护套上的受力状态密切相关;附着于基质上的传感光纤的温度系数是纤芯-护套-基质三者变形协调的结果。

To study the temperature sensing characteristics and the response to temperature variation of optical fiber sensor based on BOTDR,ten different single-mode optical fibers’ temperature coefficients under different stress state and emplaced ways are calibrated.This paper tries to analyze the impact model of temperature from the following factors： fiber jacket,temperature circle,stress state,emplaced ways and attached substratum.The results show that： the jackets’ thermal expansion rate and thermal stability are the main factors that affect the temperature sensing characteristics of optical fiber sensor;Most frequency shift-temperature curves consist of two straight lines and the temperature coefficients below the turning temperature（about 40℃） with most linear correlation coefficients over 0.995 are higher than that above the turning points;the temperature sensitivities of the sensing optical fibers are closely related to the stress states of the fiber jackets;the testing temperature coefficients are the results of deformation compatibility among fiber core,jacket and measured substratum.