光子晶体缺陷模式中,光群速大大降低可获得很高的群延时。调节光子晶体的参数可以动态地改变光子晶体缺陷模式中的光群速,从而获得可调的光延时。列举了两种动态控制光子晶体缺陷模式光群速的方法,并在仿真中进一步发现:改变光子晶体多个参数可以使禁带缺陷模式的位置不变,这时光的群速也不发生变化。得出了缺陷模式位置和其中光群速之间的关系,并且使用平面波展开法的原理证明了只有缺陷模式发生位移才能使其中的光群速变化。

In photonic crystal band gap defect mode, a long group time delay is gained when the group velocity is greatly decreased. And group velocity can be controlled actively by changing the parameter of photonic crystal. Two kinds of way which can change the photonic crystal parameter are showed. It is further found that the position of defect mode can be kept when more than one parameter is changed correspondingly, meanwhile group velocity is not changed too. It comes to the relationship between position of defect mode in photonic band gap and light group velocity, and the fact is proved theoretically by using the principle of plane wave expansion method latter.