基于表面波调制的二维三角晶格光子晶体定向辐射

A two dimensional triangular lattice photonic crystal directional radiation str ucture based on surface wave modulation

摘要:

光子晶体是高集成光通信研究的热门研究对象, 广泛应用于全反射镜、滤波器、波导 等方面。为解决二维三角晶格光子晶体波导出射端的光场控制问题,本文基于表面波调制的 概念提出了一种二维三角晶格光子晶体定向辐射的结构。该结构由X方向 10层、Z方向29层圆 形介质柱周期排列而成,在Z=0上引入线缺陷形成波导。为了获得出射光高定向性,在波导 出射端表面引入一列类似微腔的结构,其表面层介质柱相对微腔结构表面层介质柱偏离0.35a(a为晶格常数)并且半径是其它介质柱半径的1.3倍。时域有限差分法分析结果表明,该 结构具有很好的定向性,辐射距离约为61.5μm,该辐 射距离约为单波导出射端结构的4倍,并且辐射发散角度很小。

Abstract:

Photonic crystals have been extensively discussed in highly integrated optical communication research and widely applied in total reflection mirrors, filters,waveguides,and so on.In order to solve the problem of light field con trol at the exit end of two-dimensional triangular lattice photonic crystal wav e ,this paper proposes a structure of two-dimensional triangular lattice photoni c crystal directional radiation based on the concept of surface wave modulation. The structure is formed by periodically arranging a circular dielectric column o f 10layers in the X direction and 29layers in the Z direction,and introducin g a line defect into the waveguide at Z=0.In order to ac hieve high directivity, a column-like microcavity structure is introduced on the exit end surface of th e waveguide,and the surface layer dielectric column is offset from the microcavi ty structure surface layer dielectric column by 0.35a (a is a lattice constant) and the radius is three times the radius of other dielectric columns.Through a time-domain finite difference method,data analysis shows that the structure ha s quite good directivity.The radiation distance of the structure is approximatel y 61.5μm which is nearly four times the radiation distance of single waveguide structure.Besides,the present structure has a very small radiation angle.