一种双包层半径光纤布拉格光栅传感器

A fiber Bragg grating sensor for temperature-stress simultaneous measurement

光纤布拉格光栅已经成为非常有前景的温度、应力及其它参数测量的传感元件,但其存在温度和应力的交叉敏感问题。提出了一种双包层半径光纤布拉格光栅传感器,将一个布拉格光纤光栅分成两半,各自具有不同的包层半径,其中一半保持不变,另一半包层半径从62.5μm减小到40μm。实验结果表明,两半光纤布拉格光栅的温度灵敏度均为10.4 pm/°C,而应力灵敏度分别为1.12 pm/ue和3.89 pm/ue。初始的单个布拉格反射峰分裂成两个,分别对温度和应力敏感,而两个反射峰之间的波长差只受应力的影响,随着应力的增加其波长差逐渐增加。因此,通过这一个光纤布拉格光栅即可分辨出温度和应力所引起的布拉格波长漂移。该光纤光栅传感器结构简单、体积小巧、成本低廉、制作方便,可以广泛应用在各个领域实现温度和应力的同时测量。

Fiber Bragg grating（FBG） has been widely used in many fields for temperature, stress and other parameters measurement, but it has cross-sensitivity problem with temperature and stress. A dual cladding radius fiber Bragg grating sensor was presented, the FBG was divided into two halves which have different cladding radiuses, the cladding radius of one half（FBG1） was unchanged, and the cladding radius of the other half（FBG2） was decreased from 62.5 μm to 40 μm. Experimental results show that, FBG2 and FBG1have same temperature sensitivities which are 10.4 pm/° C, but FBG2 and FBG1have different stress sensitivities which are 1.12 pm/ue and 3.89 pm/ue respectively, the stress sensitivity of FBG2 is higher than FBG1 nearly 3.24 times. The initial single Bragg reflection peak split into two reflection peaks which respectively sensitive to temperature and stress, the wavelength difference between these two peaks only impact on stress. Through this sensor, it can distinguish center reflection wavelength shift caused by temperature and stress. The sensor has simple structure, small size, low-cost, and simple fabrication,and it be can widely used in various fields to achieve simultaneous measurement of temperature and stress.