Numerical studies of mode gaps and coupling efficiency for line-defect waveguides in two-dimensional photonic crystals - art. no. 155113

Using conventional waveguides. for light coupling and collection we numeric ally study band structures and transmission spectra for guided modes in lin e-defect waveguides. obtained by removing rows of air holes in a lossless t riangular-lattice two-dimensional photonic crystal. The two-dimensional fin ite-difference time-domain method combined with the effective index method and complemented with the coupled mode approximation is employed to analyze mode-gaps (or mini stopbands) arising from Bragg diffraction of the incide nt mode into the counterpropagating modes. We also show that more than 97% coupling efficiency between the ridge and the photonic crystal waveguides. is achievable by adjustment of the ridge waveguide width.