超短脉冲在光子晶体中传播时的色散参量

利用最小二乘拟合法分析了光子晶体的能带结构,定量分析了二维光子晶体的色散参量.为了考虑脉冲各频率的作用,通过引入与频率分量相关的权重因子,从而解析了群速度和平均群速度色散,进而解析出脉冲波络渐变的理论结果.通过FDTD数值模拟后,发现数值模拟结果与理论解析结果完全相吻合.本文处理光子晶体的色散参量的方法,为制作光子晶体色散器件如光子晶体色散补偿器、脉冲展宽和压缩器有一定的借鉴作用.

Evaluate the Dispersion Parameters for Ultrashort Pulses Propagating in Photonic Crystals

Using the least-squares spline approximation to analyze the photonic band structure,the dispersion parameters of a two-dimensional photonic crystal are quantitatively calculated.Considering the large bandwidth of an ultrashort pulse,average group velocity and average group velocity dispersion are achieved by introducing a weighting factor,which reveals the share of different frequency components.So the pulse evolution can be predicted theoretically.Propagation of ultrashort pulses through the photonic crystals is simulated by using the finite-difference time-domain method.The results of numerical simulations are well consistent with the theoretical predictions.This process for achieving dispersion parameters is valuable for designing photonic-crystal dispersion devices such as dispersion compensator,pulse compressor and pulse stretcher.