Slow light propagating characteristics through a two-dimensional silicon-based coupled-resonator optical waveguide

The light propagating characteristics of the coupled-resonator optical waveguides (CROWs) are studied by the finite-difference time-domain method. The circular CROWs are constructed by arranging the micro-cavities at a certain distance, which is constructed by removing the air holes along the edge of a circle from a two-dimensional (2D) triangular-lattice photonic crystal (PC). With the increasing of distance between the adjacent cavities, the group velocities of the guiding modes reduce significantly. The circular CROW studied in the paper have much minibands within the band gap, and their respective group velocities can be quite different from each other. This kind of CROW structure can provide different group velocities for the light signals with different frequencies, and avails to the separating and controlling the light signals in the all optic integrated circuits.