基于光子晶体光纤长周期光栅的双参数传感技术研究

利用高频CO2激光脉冲在折射率引导型的光子晶体光纤(PCF)上写制了长周期光栅(LPG),产生多个谐振峰。实验观察和理论分析均表明,这些峰是源于纤芯LP01模式向高阶纤芯LP11模式的耦合。通过研究产生的两个谐振峰随外界温度、弯曲、折射率和轴向应变的变化发现,LPG只对温度和轴向应变敏感,从而实现对弯曲和折射率均不敏感且能同时测量温度和应变的双参量传感器,减小了交叉敏感,其温度和轴向应变的灵敏度分别为10 pm/℃和-4.0 pm/με。

Research on the two-parameter sensing technology based on photonic crystal fiber long-period grating

We demonstrate a long-period grating(LPG) written on an index-guiding photonic crystal fiber(PCF) by CO2 laser pulse,which can produce multiple resonant peaks.The experimental observation and theoretical analysis both prove that these resonant peaks come from the coupling between the core fundamental mode LP01 and the core high-order LP11 mode.And we discuss the characteristics of two of the resonant peaks with different temperatures,curvatures,indices and tensile strains.A simple two parameter sensor,which is insensitive to the curvature and the index and can simultaneously measure the temperature and strain,is realized.The sensitivities to the temperature and the strain are 10 pm/℃ and4.0 pm/με,respectively.