基于微纳光纤耦合器的折射率传感研究

Research on Refractive Index Sensing Based on Micro-nano Fiber Coupler

目前一些超细直径的微纳光纤耦合器虽具有极高的灵敏度,然而极细的直径亦使得这些光纤耦合器非常脆弱,使得在传感应用中可能会产生一些问题:很难将这种耦合器从实验制造平台转移到微流控生物传感器中;易受环境影响而不够稳定。为了解决上述问题,分别从实验和理论上研究一种直径为6.25μm的微纳光纤耦合器,这种光学耦合器在外部折射率(refractive index, RI)为1.339 8时能达到-1 753 nm/RIU的高折射率灵敏度。基于有限元分析方法(finite element method, FEM),计算出偶/奇模的有效折射率和折射率灵敏度并与实验测试结果比对。本文制作的光纤耦合器可以很好地运用在光纤微流控生物传感等其他实验室芯片上的多功能传感中,有良好的实用前景。

Although some conventional high-sensitivity optical microfiber couplers with ultra-thin diameter have been reported,the reported optical microfiber couplers with very fragile properties can pose great challenges in real sensing applications.In order to address the above problem,an optical microfiber coupler with a broad diameter of 6.25μm was studied experimentally and theoretically.This optical microfiber coupler can achieve a high refractive-index sensitivity of-1753 nm/RIU at the external refractive index(RI)of 1.3398 with good stability.Based on finite element method(FEM),and effective indices of even/odd modes and refractive index sensitivity can be calculated.By this way,the proposed optical microfiber coupler can find proper applications in fiber-optic micro-fluidic biosensor and lab-on-a-chip multifunctional sensing.