双芯光子晶体光纤中的模式干涉

Modal interference in dual-core photonic crystal fibers

应用全矢量超格子叠加模型分析了双芯光子晶体光纤 (PCF)的模式特征 .双芯PCF的基模和二次模分别由偏振方向不同的两个偶模和两个奇模组成 ,讨论了这四个模式的模式电场奇偶性 .基于对双芯PCF模式电场奇偶性的认识 ,讨论了光纤中的矢量模式干涉问题 .分析表明 ,不同偏振态模式的干涉不会引起芯间的功率转移 ,双芯PCF的芯间功率耦合是由相同偏振模式的干涉引起的 .在相同偏振模式干涉过程中 ,光功率在两个芯子中呈余弦振荡 ,光纤的两个芯子一般存在约π/ 2的相位差 .

The modal characteristics of dual core photonic crystal fibers(PCFs) are analyzed by a full vector supercell lattice overlapping model. The fundamental and second order modes of dual core PCFs consist of a pair of even and odd modes with different polarization. The parity properties of the modal electric field for the fundamental and second order modes are discussed. Based on the analysis of parity of the modal electric fields, we investigated the vector modal interference in dual core PCFs.It is the interference between two same polarized modes that contributes to the inter core coupling of power. It is shown that the optical power will oscillate from one core to the other and the phase difference between both cores is about π/2. The dependence of coupling coefficients for different polarization on wavelength is discussed.