【摘要】 通过研究2维正方晶格光子晶体波导多模干涉的自映像效应,优化设计了一种新型1×2光子晶体波导分束器,采用时域有限差分法对其传输特性进行模拟分析。设计过程中,根据多模干涉耦合区中周期出现的双重像的位置确定两个单模输出波导的位置,通过在分束器输入和输出耦合区的连结处设置介质柱,改变输入和输出耦合区中的模场分布,实现模式匹配,从而明显减小分束器的反射损耗。计算结果表明:设置的介质柱归一化半径分别为0.08和0.177时,对于波长为1.55μm的入射光,该分束器的透射率可高达93%。更多还原

【Abstract】 A novel photonic crystal 1×2 splitter is designed based on the self-imaging of multimode interferences in the two-dimensional square photonic crystal waveguides. The transmission characteristics of the splitter is analyzed numerically by the finite-difference time-domain method. In the design process of the photonic crystal waveguide splitter with two out ports,the positions of output waveguides are decided by the positions of the twofold image formed by the self-imaging effect of multimode interferences. The reflective losses are obviously decreased by inserting the dielectric rods,which can vary and match the mode field of the coupling zone,lying at the junctions between the multimode waveguide and single-mode waveguide. The results show that the transmittance of this splitter can be as high as 93% for 1.55 μm wavelength when the normalized radius of dielectric rods are 0.08 and 0.177.更多还原