一种模拟倾斜折射率界面光波导的新方法

A highly efficient beam propagation method for modeling step-index waveguides with tilt interface

针对传统离散格式下,束传播方法(BPM)模拟倾斜折射率界面出现的问题,提出了一种简明且易于编程实现的改进方案.在横向上,通过坐标系变换和插值处理,以新颖的7点差分格式代替传统的5点差分方式;在纵向上,以四阶显式Runge_Kutta方法(RKBPM)代替二阶Crank_Nicholson算法(CNBPM),避免了求解不规则矩阵方程,从而使计算效率显著提高.

Based on a new finite-difference scheme and Runge-Kutta method together with transparent boundary conditions（TBCs）, a novel beam propagation method to model step-index waveguides with tilt interfaces is presented. The modified scheme provides an precies description of the tilt interface of the nonrectangular waveguide structure, showing a much better efficiency and accuracy comparing with the previously presented formulas.