基于光子晶体波导和腔耦合的光单向传输结构

Unidirectional Light Propagation Structure Based on Coupling between Photonic Crystal Waveguides and Cavity

设计并优化了一种紧凑、简洁易实现的光单向传输结构,该结构基于硅柱型二维正方格子光子晶体,以空气为背景材料,在光子晶体中引入两个相互垂直的线缺陷形成波导W1和W2,同时引入点缺陷形成腔连接两个波导,利用腔和两个波导之间模式的匹配与否,实现单向传输。设计的单向传输中心波长为通信波长1.55μm。当偶模式的入射光在该结构的W1→腔→W2光路上传输时,由于腔模式和两侧的波导模式均匹配,光路导通,中心波长处透射率达到96.5%;而同样模式的光在逆向W2→腔→W1光路上,由于W2内传播的光模式和腔模式不匹配,无法耦合到腔中,透射效率几乎为0。本结构的仿真和光的传输特性分析是应用COMSOL和Rsoft软件实现的。该结构在未来的全光集成电路中有可能得到广泛应用。

A compact and concise unidirectional propagation structure was designed based on two-dimensional square lattice photonic crystals of silicon rods in air for the near-infrared light around 1.55μm.And it is easy to prepare the structure for its conciseness.In the photonic crystal,two line defects were introduced to form waveguides W1 and W2,and one dot defect was introduced to form a cavity to connect the two waveguides.When the light of even mode incidences from W1,propagation is along W1→cavity→W2,the modes in W1 and W2 match well with the cavity mode,light will propagate through the structure with high transmittance of as high as96.5%.When light of the same mode incidences from W2,mode in W2 mismatches with mode in the cavity,light propagation is blocked with transmittance nearly 0%.COMSOL and RSoft were used to simulate and analyze the light propagation.The structure could be widely used in the future all-optical integrated circuits.