Structural dependence of coupling between a two-dimensional photonic crystal waveguide and a wire waveguide

The coupling dependence between a wire waveguide and a two-dimensional photonic crystal waveguide on a shared connection structure was analyzed theoretically. By calculating the transmittance at the connecting point for various sample geometries, we found the structure to have high coupling efficiency and fabrication tolerance. The maximum transmittance can be as high as 95% for a wavelength near 1.55 μm within our investigation when the structure of the connecting point is well designed.