光纤布拉格光栅法布里-珀罗干涉式传感器灵敏度

Sensitivity of Fiber Bragg Grating-Based Fabry-Pérot Interferometric Sensor

在光纤布拉格光栅法布里-珀罗干涉式(FBGFPI)传感器的实验研究和工业应用中,其灵敏度一直受到广泛关注。在考虑光源线宽的情况下,推导出了其灵敏度的理论表达式,讨论了光源相干长度、法布里-珀罗(F-P)腔腔长及光栅反射率对灵敏度的影响,指出腔长与光源相干长度比值越小,灵敏度越高;在腔长与光源相干长度比值一定时,存在一个最佳反射率使灵敏度达到最大。最后通过不同腔长的灵敏度对比实验和不同反射率的灵敏度对比实验,验证了理论仿真结果的正确性。

In the experimental research and industry applications of the fiber Bragg grating-based Fabry-Perot interfirometric（FBG FPI） sensor,its sensitivity has been widespread concerned.Considering the linewidth of the light source,the power transmission coefficient is amended and the theoretical formula of the sensitivity is deduced.Then,the key influence factors on the sensor sensitivity are discussed,including the cavity length,the coherence length of the light source,and the reflectivity of the FBG.The results show that the smaller the ratio between the cavity length and the coherence length is,the higher the sensitivity will be.When the ratio is chosen,there is an optimum reflectivity.If the reflectivity of FBG equals the optimum,the sensitivity is the highest.The results of comparison experiment on the sensitivity with different cavity lengths and sensitivity experiment on different reflectivities verify the correctness of the theoretical simulation.