研究了二维光子晶体耦合腔波导的结构对慢光特性的影响,发现微腔间的距离n、填充因子r/a和缺陷柱的尺寸rd是影响光子晶体禁带中慢光导模传输特性的重要参数。随着缺陷微腔间距离的增加,导模群速度vg急剧减小;当填充因子和缺陷柱尺寸增加时,导模向低频方向移动,同时,导模群速度降低;填充因子和缺陷柱尺寸降到一定数值后,vg达到最小值,此后,当r和rd分别超出其特定值继续增大,导模群速度反而增大。取微腔之间介质柱个数为6,普通介质柱尺寸为r=0.22a,a为光子晶体晶格常数,缺陷柱尺寸为rd=0.12a,得到导模群速度最大值vgmax<1.93×10-3 c,带边处vg<10-4 c(c为光速)。这一结果显示,通过基本结构设计可以实现对光子晶体耦合腔光波导中慢光的有效控制,这将为基于光子晶体功能器件的设计和应用提供有效的支持。

Structure parameters of the slow light in the photonic crystal coupled resonator optical waveguide have been investigated. It is found that cavity distance n,filling factor r/a and size of the defect rod rd are the most significant factors affecting the transmission properties of the slow light guided mode in the photonic band gap. With the increase of cavity distance,the group velocity vg of guided mode decreases rapidly. When filling factor and defect rod size increase,the guided mode shifts towards a lower frequency with vg decreasing simultaneously. When the filling factor and defect rod size increase to a respective certain value,vg reaches a bottom value. And as r and rd exceeds the above certain value,group velocity of the guided mode will increase. By choosing appropriate structure parametersm of n=6,r=0.22a,rd=0.12a,it is obtained that the maximum value of guided mode vgmax=1.93×10-3 c and vg<10-4 c at the band edge in the photonic crystal coupled resonator optical waveguide. These results indicate that effective control over the slow light in the photonic crystal coupled resonator optical waveguide could be realized through basic structure design,which may offers significant support for design and application of functional devices based on photonic crystals.