变迹和啁啾光子晶体的特性研究

构造了变迹和啁啾的光了晶体结构，用时域有限差分(FDTD)法分析了它们的响应特性。分别对不同啁啾系数的光子晶体结构和不同变迹形式的光子晶体结构进行了比较分析。研究表明．啁啾结构的光子晶体与普通结构的光子晶体相比．禁带的带宽增加了，禁带的中心频率向低频处偏移．当啁啾系数在0～0．01之间以0．002变化率增加时．随着啁啾系数增大．禁带的宽度变大，禁带的中心频率减小：同样构造的线性变迹的光子晶体和正弦变迹的光子晶体对于光子禁带的中心频率和宽度有类似的影响。

The Characteristic Studies in Photonic Crystal with Chirped and Apodized Structures

The chirped photonic crystal and the apodized photonic crystal are constructed, and the characteristics of them are studied by finite-difference-time-domain (FDTD) method and perfectly matched layer (PML) technology. The different photonic crystal structures with different chirped coefficients, and with different apodized functions are compared. The result shows that the width of the bandgap in chirped photonic crystal is larger than the one of ordinary photonic crystal, and the center frequency of the bandgap is moved to the lower frequency. When the chirp coefficient increases as 0.002 in the range of 0 to 0.01, the width of the band becomes wider and the center frequency of the band is lower. The apodized function has analogic effect to the center frequency and the width of the bandgap.