一种实现光子晶体波导定向耦合型多路光均分的新方法

将多光子晶体单模波导平行、邻近放置构成定向耦合器. 依据自映像原理，数值分析了输入光场对称入射时，该系统中光的传播行为. 基于此结构，以三、四通道为例，设计了超微多路光分束器，并仅通过对称地改变耦合区中两个介质柱的有效折射率，使光场在横向发生重新分布，实现了输出能量的均分或自由分配. 和已报道结果相比，此调制方法更为简单易行而且效率更高，并可以推广到具有更多输出通道的光分束器中，在未来的集成光回路中具有广泛的应用价值. 关键词： 光子晶体波导 定向耦合器 分束器 能量均分

A new way of uniform splitting of the optical power by directional coupling between the photonic crystal waveguides

Directional coupler can be constructed by putting multiple photonic crystal waveguides together. The propagation of the optical field entering this system symmetrically was analysed numerically according to self-imaging principle. On the basis of this structure, ultracompact multiway beam splitter was designed and the ones with three and four output channels were discussed in details as examples. By simply tuning the effective refractive index of two dielectric rods in the coupler symmetrically to induce the redistribution of the power of the optical field, uniform or free splitting can be achieved. Compared with the reported results, this way is simpler, more feasible and more efficient and has extensive practical value in future photonic integrated circuits.