镀膜双峰谐振长周期光纤光栅折射率传感的优化设计与实验  

Optimal Design and Experiments of Coated Dual-Peak Resonance Long-Period Fiber Grating Refractive Index Sensing

作　　者：蒋秀丽[1,2] 顾铮■ 凌强[1] 蓝锦龙[1] 

机构地区：[1]上海理工大学光电功能薄膜实验室,上海200093 [2]上海电力学院数理学院,上海200090

出　　处：《中国激光》2016年第5期122-129,共8页Chinese Journal of Lasers

基　　金：国家自然科学基金(60777035);教育部科学技术研究重点项目(208040);上海市教育委员会科研项目(07ZZ87);上海市重点学科建设项目(T0501);沪江基金(B14004)

摘　　要：利用镀自组装薄膜的双峰谐振长周期光纤光栅（LPFG）实现了高灵敏的折射率传感,给出了提高镀膜双峰谐振光纤光栅对环境折射率（SRI）灵敏度的途径。确定最佳镀膜厚度,使光纤包层模位于模式转换区附近;调整光纤半径,使镀膜后光栅的双峰位于相位匹配转折点（PMTP）附近,给出了确定最优膜厚和光纤半径的方法。将不同半径的双峰光栅镀自组装聚丙烯胺盐酸盐（PAH）/聚丙烯酸（PAA）薄膜后,放入不同浓度的葡萄糖溶液中进行折射率传感实验。结果表明：通过优化光纤半径和薄膜厚度,镀膜后工作于模式转换区附近和PMTP附近的双峰光栅对1.333-1.372范围内折射率的灵敏度高达3985nm/RIU（RIU为单位折射率）,明显高于不在模式转换区或PMTP附近的光栅,亦高于已报道的非双峰镀膜长周期光纤光栅。Highly sensitive refractive index sensing is realized by using dual-peak resonance long-period fiber grating（LPFG）with self-assembled coating.The way for improving the sensitivity of coated dual-peak resonance fiber gratings to the surrounding refractive index is given.The fiber cladding mode is located near the mode transition zone by choosing optimal film thickness.The dual-peak structure of fiber coated is located near phase-matching turning point（PMTP）by adjusting the fiber radius.The method for determining optimal film thickness and fiber radius is given.Dual-peak gratings with different fiber radii coated with poly allylaminehydrochliride（PAH）/poly acrylic acid（PAA）films are immersed in different concentrations of glucose solution to carry out refractive index sensing experiments.Results show that the sensitivity of coated dual-peak gratings operating near mode-transition regions and PMTP is 3985nm/RIU in 1.333-1.372 index range,which is obviously higher than those of gratings not operating near mode-transition or PMTP,and also higher than that of non-dual-peak coated LPFGs reported.

关 键 词：光纤光学 光纤折射率传感 长周期光纤光栅 双峰谐振 模式转换 

分 类 号：TN253[电子电信—物理电子学]