为了优化双芯光子晶体光纤耦合器的耦合性能,采用改变两纤芯间空气孔的结构和孔内折射率的方法,得到了双芯光子晶体光纤耦合器的优化模型。基于光束传播法数值分析出两纤芯间空气孔尺寸以及孔内注入材料折射率的变化对双芯光子晶体光纤耦合器的耦合性能的影响。结果表明,由于光纤的整体结构不变,使得光纤损耗系数保持不变;减小双芯间的空气孔孔径或增大孔内折射率都会使耦合器的耦合长度减小,两不同偏振方向的耦合长度差异减小,损耗减小;双芯间空气孔内折射率可调性强,使得光纤耦合器的耦合性能有易调节的优点,为设计双芯光子晶体光纤耦合器的优化模型提供了理论支持。

In order to improve coupling character of dual-core photonic crystal fiber coupler,optimum models of dual-core photonic crystal fiber coupler were obtained by changing the structure and the refractive index of the air hole between both cores.Based on beam propagation method,the effect of the dimension of air hole between the cores and the refractive index of the injected material on the coupling property of the dual-core photonic crystal fiber coupler was analyzed by numerical calculation.Results of numerical calculation showed that the loss coefficient of the fiber maintained constant because the whole structure of the fiber kept unchanged.No matter the air hole between both cores decreased or the refractive index increased,the coupling length became shorter,the difference between coupling length for both polarized light became smaller and the loss became lower.Furthermore,it was easy to modulate the coupling character for the refractive index in the air hole between both cores was easy to adjusted.This method provides theoretical support for the optimum design of the models of dual-core photonic crystal fiber coupler.