用FDTD法建模波导器件时数值色散的仿真研究

时域有限差分法(FDTD)在电磁场数值计算中占有重要的地位。但是,由于时域有限差分法只是原Maxwell旋度方程的一种近似,当在计算机的存储空间对电磁波的传播进行模拟时,即使是在非均匀介质中也会出现色散现象,且电磁波的相速度随波长、传播方向及变量离散化的情况而发生变化。受计算机存储空间和计算速度的限制及色散机理的多样性和复杂性,少有文献对此进行精确定量的数值分析。本文通过对平面光波导在不同时间步长和空间步长时光场分布的仿真,探讨了减小FDTD法数值色散的具体措施,对改进FDTD法固有缺陷和提高FDTD法计算精度具有直观的理论指导,为复杂波导器件的设计和制造提供了预测手段。

Simulation research on numerical dispersion for modeling of wave guide devices by FDTD

FDTD is playing a key role in electromagnetic field computation. But the FDTD only approximates to the Maxwell curl equation.When electromagneti c wave propagation is simulated in storage space in computer,the dispersion wou ld occur even in non-uniform medium,and the phase velocity of electromagnetic w ave would change according to wavelength or the direction of propagation and th e discretization error.There are few documents that carry on accurate and quant itative numeric analysis to this because of Variety and complexity of dispersion mechanism and restricting by computer memory space and computational speed.Ba sed on optical field distribution of plane wave-guide through different time ste p and space step,this paper probes the concrete measure of reducing the numeric al dispersion,it has visual theory directive significance to improve FDTD law i nherent defect and raise FDTD law calculate precision and it has offered the mea ns of predicting for design and manufacture of the complicated wave guide device.