Efficient High-Spatial-Order FDTD Analysis of 3D Optical Ring Resonator Filters

A high-spatial-order scheme of the finite-difference time-domain (FDTD) method has been applied to the three-dimensional (3D) full wave analysis of optical dielectric rib-waveguide circuits such as ring resonator filters. Due to the electrically large nature of the 3D optical circuits, the FDTD analysis of them has been significantly restrictive in computation. Precise investigation into the numerical dispersion of high-spatial-order schemes suggests the possibility of employing coarse discretization. By applying the high-spatial-order schemes to those problems, by virtue of their highly linear numerical dispersion property, we have achieved significant reduction in the number of cells compared to the standard FDTD, thus being capable of dealing with larger structures. The accuracy and the required computational resources are also compared.