两种封装的光纤光栅温度传感器的低温特性

介绍了光纤光栅(FBG,Fiber Bragg Gratings)温度传感器的两种封装形式。推导了两种FBG温度传感器的温度敏感因素并进行了实验验证。实验研究了两种FBG温度传感器在-70~0 ℃的中心波长低温变化特性,比较了相同条件下两种FBG温度传感器的实验结果。结果表明:细不锈钢管封装的FBG温度传感器的中心波长在-60 ℃时发生了突变,急剧下降;而镀金FBG温度传感器的中心波长在-70~0 ℃随温度线性变化,重复性较好并且几乎没有迟滞现象。两种传感器在线性变化区间的温度灵敏系数KT 分别为28.2 pm/ ℃和21.3 pm/ ℃,分别是裸光纤布拉格光栅的3倍和2.3倍,它们的线性拟合度都超过0.999。

Low temperature properties of fiber Bragg grating temperature sensors with two package methods

Two package methods of Fiber Bragg Grating(FBG) temperature sensors were introduced. The temperature sensitive factors of the sensors were derived analytically and verified by experiments. The experiment results of two kinds of FBG temperature sensors in identical conditions were compared by analyzing the variety properties of center wavelength from -70℃ to 0℃. From the experimental results,it is shown that the center wavelength of FBG temperature sensor with thin stainless steel tube package falls sharply at -60℃; while there is a very good linearity and preferable repeatability between the center wavelength of FBG with gold package in the temperature change from -70℃ to 0℃, and almost no hysteresis effect. The sensitivities KT of two temperature sensors are 28.2 pm/ ℃ and 21.3 pm/ ℃ respectively during linear change, and they are 2.89 and 2.28 times as large as that of a bare FBG. Their pertinence coefficients are more than 0.999.