标量FDTD法分析渐变折射率光波导模场分布

用标量时域有限差分法（Finite-differece Time-domain Method,FDTD法）分析了渐变折射率平面光波导中基模的模场分布情况，采用平面光波、球面光波、高斯光波等5种不同形态的光波激励同一波导，借助计算机进行数值求解，得到的光场分布图在光场传播达到稳定后完全相同，说明波导的模式与光波形态无关，只与波导结构和光波波长有关，结果表明该方法直观、精确、快速，并与解析法分析的结果一致。

The analysis of mode field distributions of the graded index optical waveguide by the scalar FDTD

This paper analyzes the mode field distributions TE 0 mode of the graded index planar waveguides by the scalar finite difference time domain (FDTD). Five kinds of optical sources are used as stimuli when analyzing the same waveguide, namely plane optical wave, Guass optical wave and spherical wave etc. The numerical solutions are resolved by computer, the final figures of mode field distributions are the same after the steadily spreading optical waves that indicate that the distributions of the stable optical fields have nothing to do with the stimulated optical waves. The distributions are just connected with the structural parameters of the optical waveguide and the optical wavelength. The result is direct viewing, precise, rapid and identical to the discussion by the analytic method.