Efficient coupling between a photonic crystal waveguide and a nanometer waveguide with an asymmetric resonator

A new approach to achieve efficient coupling between photonic crystals and a nanometer waveguide via an asymmetric resonator is proposed. The asymmetric resonator was composed of the photonic crystal and the nanometer waveguide was constructed by elongating a rod of the photonic crystal resonator horizontally. By introducing the asymmetric resonator, the nanometer waveguide served as a part of the resonator, and the coupling between the photonic crystal waveguide and the nanometer waveguide was converted to internal coupling between the photonic crystal devices. The 3D theoretical coupling efficiency reached 91.31%. Such compact, efficient coupling shows great promise for applications in molecular imaging, nanoprobes, integrated photonic circuits and on-chip optical interconnects.