光子晶体光纤模式的简并特性研究

Study on mode degeneracy in photonic crystal fibers

应用光子晶体光纤 (PCF)的全矢量模型 ,根据对称性分析 ,按照最小波导扇面及相应的边界条件 ,将PCF中的模式进行了分类 ,并将PCF中的模式类比阶跃光纤来命名 .分析表明 ,PCF中的模式或者为非简并的 ,此时能够反映波导结构对称性 ;或者为简并对 ,必须二者组合才反映波导结构的对称性 .当简并对中的两个模式都具有与PCF波导结构相同的对称性时 。

A novel full vector model is applied to analyze the photonic crystal fibers (PCF). From symmetry analysis of modes of a waveguide, we classify the modes of PCF into nondegenerate or degenerate pairs according to the minimum waveguide sectors and its appropriate boundary conditions. We present the modes of PCF that can be labeled by its step index fiber analogs. It is shown that these modes either exhibit the full waveguide symmetry and nondegenerate or occur in degenerate pairs that support this symmetry only in combination. The doublet of the degenerate pairs in which both have the same symmetry as PCF will be split into two nondegenerate modes.