一维类梳状波导光子晶体的频率带隙宽度

The Width of Frequency Band Gap in One-dimensional Comb-like Waveguide Photonic Crystals

一维类梳状波导是由在一维主链上周期性接枝而形成的光子晶体 .利用界面响应理论可导出波导的色散关系 ,据此分别讨论了这种光子晶体的带隙宽度与波导接枝参数之间的关系 .接枝的介电常数和长度的变化将会使对带隙的宽度发生改变 ,通过数值计算发现 ,对于不同类型的接枝 ,参数变化引起的带隙宽度的变化趋势基本相同 ,而不同的参数产生的影响则有很大差别 .特别的 ,当参数变化至某些特定点时带隙将会消失 ,这和其他类型的光子晶体完全不同 ,带隙的消失不是因为缺陷而仅仅是因为参数改变的影响 .

The frequency band gaps of one-dimensional comb-like waveguide photonic crystals were investigated. This kind of photonic crystal was formed by periodically grafting branches along an infinite monomode waveguide. The dispersion relation was obtained in a closed form by using the interface response theory (IRT). Based on the analysis of the relation between the width of the frequency band gap and the parameters of grafted branches, the effects of the dielectric constant and the length of grafted branches upon the width of the band gap were studied, and the numerical calculation results were given. In particular, the frequency band gap vanished when dielectric constant and the length of grafted branches were at some given values, and this was different from other kinds of photonic crystals.