光纤法布里-珀罗复合结构折射率传感器的灵敏度分析

摘要

理论上推导了光纤法布里-珀罗复合结构传感器的反射光谱条纹对比度与外界介质折射率的关系,并分析了实验参数对传感器灵敏度的影响.利用化学腐蚀渐变折射率多模光纤制作了光纤法布里-珀罗复合结构折射率传感器,空气中的条纹对比度可达30 dB以上,折射率测量的灵敏度达45 dB/RIU(refraction index unit,简RIU)以上.实验结果与理论符合很好.通过理论和实验分析,提出了进一步提高传感器灵敏度的方法.%Theoretical expressions for analyzing the refractive-index sensitivity of the hybrid optical fiber Fabry-Perot sensor is developed. Influence of the experimental parameters on the measurement sensitivity is discussed. Hybrid optical fiber Fabry-Pérot sensor is fabricated by chemically etching a graded-index multimode fiber ( GI-MMF) , fusion splicing it into a single mode fiber, and cleaving the GI-MMF. The fringe contrast exceeds 30 Db and the corresponding measurement sensitivity of refractive index is about 45 Db per refraction index unit. Experimental results are in good agreement with the theoretical ones. It is indicated by the numerical simulations that the performance of this kind of sensor can be further improved.