An Analysis of Photonic Crystal Waveguide Gratings Using Coupled-Mode Theory and Finite-Element Method

摘要

Photonic crystal waveguide gratings are proposed and their coupling coefficients and transmission characteristics are effectively investigated by using a simple coupled-mode theory combined with finite-element method. The results obtained here are compared with the results obtained by using full numerical simulation method. A new definition for unperturbed waveguides is introduced to obtain accurate coupling coefficients. Limitations of coupled-mode theory are also discussed by numerical examples: high index contrast waveguide gratings and photonic crystal waveguide gratings.