根据光子晶体中波导与腔的耦合特性, 设计了一种由波导与环形腔耦合实现窄带滤波的光子晶体结构。用有限元法分析了环形腔不同结构参数对各个端口透射光功率谱的影响, 由此可以根据所需波长要求设计不同结构的环形腔滤波器结构, 并可通过改变边界散射介质柱的排列和环形腔边界介质柱的半径, 减少波导与环形腔之间的散射损耗, 达到最佳滤波效果。文章可为密集波分复用系统中光学滤波器的集成以及窄带滤波器的设计提供一定的参考。

In this paper, we present an optical add-drop filter design on the basis of the coupling properties between waveguide and the ring resonators in photonic crystal. We investigate the normalized transmission spectra for varied ring configurations by using a two-dimensional finite element model in a square lattice dielectric-rod photonic-crystal structure and achieve both backward- and forward-dropping by controlling the size of the ring resonators and the refractive index of the dielectric-rod in the ring resonators. On the other hand, by changing the arrangement of the column boundary scattering medium and the size of column radius of the ring cavity boundary medium, we can reduce the scattering loss between the waveguide and the ring cavity so as to achieve the optimum filtering effect.