一种同时测量温度和应变的光纤光栅传感器

报道了一种新型实用的用单根光纤布拉格光栅(FBG)实现温度和应变分离传感的技术。当光纤光栅一部分包层直径变小时，整个光栅可以看成由两个周期相同但直径不同的子光栅连接而成。理沦分析和实验都证实了这两个子光栅具有相同的温度敏感性和不同的应变敏感性．由此实现光纤光栅传感器中温度和应变两参数的分离测量，而且这两个子光栅的中心波长间距可以直接测量应变大小．温度变化不影响所测量的应变值。实验中光栅的一部分包层直径被HF酸腐蚀到82μm．获得了两子光栅应变响应系数分别为0．00201nm/με．0．000858nm/μ

A new practical technology for separately sensing of strain and temperature using a single fiber Bragg grating (FBG) is proposed and demonstrated. The FBG can be think to be a grating composed of two inner FBGs with the same period but different diameter when a part cladding diameter of the FBG is decreased. Theoretical analysis and experiment data show that the two inner FBGs have the same temperature response but different strain response. So the strain and temperature responses can be measured separately and the span between the two inner FBGs can be used to measure the temperature-independent strain. In experiment, a part of cladding diameter of a FBG is decreased to 82 μm by etching it in HF acid. The strain responses of two inner FBGs are 0.00201 nm/με and 0.000858 nm/με, respectively, the strain response of the span between two inner FBGs is 0.00116 nm/με, and the temperature responses of two inner FBGs both are 0.01 nm/℃. Based on these experiment data, the strain and temperature can be simultaneously measured using a single FBG.