熔锥型光纤耦合器折射率传感特性研究

摘要

Waveguide structure model of fused taper fiber coupler in micron dimension was constructed.The optical power distribution change in fused taper fiber coupler model was gotten by numerical simulation with beam propagation method,and change rule of coupler output spectrum response was analyzed and obtained in different refractive inde-xes.According to fiber evanescent field coupling theory in micron dimension,the sensing experimental platform of fused taper fiber coupler was set up,and the changing relationship between transmission spectrum and surrounding su-crose solution refractive index was studied.The theoretical simulation and the experimental results show that with sur-rounding sucrose solution refractive index ranging from 1.3330 ~1.4000,transmission spectrum shift of sensing sys-tem has good linear relationship with surrounding refractive index changes,and the response sensitivity reaches 2272.7569 nm/RIU.This refractive sensor system has merits of wide measurement range,fast response,small size and simple fabrication.%构建了熔锥型光纤耦合器微米量级下的波导结构模型.利用光束传播法对光功率在熔锥型光纤耦合器模型中的分布变化进行了数值模拟,分析得到了在不同折射率环境下耦合器输出光谱响应图的变化规律.依据微米量级光纤倏逝场耦合模理论,搭建基于熔锥型光纤耦合器结构模型的传感实验系统,研究了其透射光谱与外界蔗糖溶液折射率的变化关系.理论模拟和实验结果表明,当外界环境溶液折射率在1.3330~1.4000范围内变化时,传感结构透射光谱的漂移与折射率变化呈现良好的线性关系,响应灵敏度能够达到2272.7569 nm/RIU.该折射率传感结构测量范围宽,响应速度快,结构紧凑,传感光路搭建操作简单.