平面光波导光场分布的有限时域差分法计算

CALCULATION OF THE FIELD-INTENSITY PATTERN IN OPTICAL PLANAR WAVEGUIDE BY THE FINITE-DIFFERENCES TIME-DOMAIN METHOD

用有限时域差分法计算了简单三层对称平面光波导中的光场 ,得到了任意截面上光场的分布 .这一方法的优点在于它能完全模拟波导中光场的时域特性 ,使波导中的光传播完全可视化 ,模拟横向传播 ,提取光在波导中的传输模式 ,也可用于有源波导的计算如光波导放大器 .有限时域差分法直接求解依赖时间的麦克斯韦旋度方程 ,利用二阶精度的中心差分近似 ,把旋度方程中的微分符直接转换为差分形式 .每一步计算都无须作矩阵求逆运算 ,因此 ,比其他数值计算方法更有效。

The optical field distribution of arbitrary profile in three layer symmetry planar waveguide is calculated by the Finite differences Time domain method (FD TD) in this paper.The principle advantage of this method is that it enables a full visualiztion of how the light travel within waveguide,simulates transverse propagation;fetches propagating mode which exists in the waveguide;simulates active devices such as optical amplifiers.Since FD TD directly solves the time dependent Maxwell cural equation,using two order center difference approximate transfer the differential symbol directly to differences,every step does not carry out matrix inverse,it is more effective and precise than other numerical methods.