一种基于组合型FBG的快速双参量测试系统

A fast two-parameter test system based on combined FBG

应变和温度是光纤光栅系统中主要的两个参量,而其又存在交叉敏感问题。为了同时获取此双参量,降低交叉敏感的影响,设计了一种基于组合型FBG的测试系统。依据不同芯径大小的应变效果不同的原理,研究了一种组合型FBG。在计算波长偏移量与应变、温度关系的基础上,推导了波长偏移量的相关函数,并分析了的耦合方式及耦合效率。实验中,采用光源、传输光纤、组合型FBG等完成了对应变、温度的测试。结果显示组合型FBG随温度变化时,波长偏移量基本一致。但应力变化时,斜率变化差异较大。最终,对不同条件下应变和温度进行测试,标定了组合型FBG温度、应变的响应系数。由此可见,通过检测组合型FBG的波长偏移量可以实现对温度和应变的同时解析。该设计无需熔接、拉锥等复杂工艺,结构简单、扩容兼容能力强,具有很高的应用价值。

Strain and temperature are two main parameters in fiber grating system,while there are cross-sensitive problems. In order to obtain this two-parameter at the same time,and to reduce its influence,a test system based on combined FBG is designed. Based on different effect of different core diameter strain,a kind of FBG probe is studied.On the basis of calculating the relationship between wavelength offset and the strain and temperature,the correlation function is deduced,and the coupling mode of the probe and the coupling efficiency are analyzed. In the experiment,strain and temperature test were completed by using light source,transmission fiber,combined FBG and so on. The results show that the wavelength offset is basically the same when the FBG changes with temperature. However,the slope change is quite different when stress changes. Finally,the strain and temperature were tested under different conditions,and the response coefficients of FBG temperature and strain were calibrated. It can be seen that the simultaneous analysis of temperature and strain can be achieved by detecting wavelength offset of combined FBG. The design is no need to weld,taper and other complex technologies. It has simple structure,strong capacity expansion capability and has high application value.