光纤Bragg光栅在77K环境下的温度传感性能研究

Study on Temperature Characteristics of Optical Fiber Bragg Grating Under the 77 K Environment

进行了从液氮温度(77 K)到室温(286 K)的光纤Bragg光栅(FBG)温度传感性能的实验研究。结果表明,FBG的温敏系数与温度相关。低于210 K,FBG的温敏系数变小,这将限制低温环境下FBG作为温度传感器的使用。通过在裸FBG外部涂敷热膨胀系数为61×10-6的丙烯酸脂材料,可以显著提高FBG的温敏系数和线性度。80 K时,有丙烯酸脂包层材料的FBG温敏系数为0.01526 nm/K,而同温度条件下裸FBG的温敏系数仅为0.00449 nm/K。

The temperature sensing capacity of fiber Bragg grating（FBG） sensors from 77 K to 286 K is studied. It is found that the temperature sensitivity of FBG is dependent on the temperature. Below 210 K, the temperature sensitivity became smaller which seriously limits the application of FBG as temperature sensor in cryogenic environment. However,coating material-Acrylate with larger coefficient of thermal expansion about 61 X 10-6 ,can greatly improve the temperature sensing ca pacity of FBGs. At 80 K,the temperature sensitivity of Acrylate coated FBG is 0. 015 26 nm/K that is better than 0. 004 49 nm/K of the bare FBG at the same temperature.