基于二维光子晶体的多频段太赫兹波滤波器研究

基于二维光子晶体,提出一种多频段 太赫兹(THz)波滤波器。在光子晶体中引入3条平行的横向波导,通过改变介质柱的半 径或插入半径较小的介质柱在 相邻波导之间构成耦合区域,使特定频率的THz波从中部波导耦合至上、下侧光子晶体波 导并分别从端口2和1输出, 其余的THz波经中部波导从端口3输出,最终达到多频段滤波的效果。利用时域有限差 分法和平面波展开法对所提出 的器件计算和仿真结果显示,频率为f=3.24和3.75THz的THz波分 别从端口1、2和3输出中,传输效率分 别达到95%和99% ,表明本文结构能很好实现多频段滤波效果。

A multi-band terahertz wave filter based on 2-D photonic crystal

Based on 2-D photonic crystal,a multi-band terahertz (THz) wave filter is pro posed in this paper.Three parallel transverse waveguides are introduced into pho tonic crystal.By changing the radius of some rods and inserting some rods with smaller radius,we can acquire two coupling regions between two adjacent waveguides.The THz wave with specific frequency can be coupled from the middle waveguide to the upside photonic crystal waveguide through the coupling region a nd output from Output1,while the THz wave with another specific frequency can be coupled from the middle waveguide to the downside photonic crystal waveguide through the coupling region and output from Output2.The rest passes through the middle waveg uide directly and is output from Output3.Finally,we can obtain a multi-band THz wave filter.Both the finite-difference time-doma in method and the plane wave expansion method are used to calculate and simulate the performance of the proposed device,which shows that the terahertz waves whose frequences are 3.24THz,3.6THz and 3.75TH z can be output from Output1,Output2and Output3res pectively,whose transfer efficiencies are 95%,98% and 99% respectively.