Propagation and second-harmonic generation of electromagnetic waves in a coupled-resonator optical waveguide

Using both the tight-binding approximation and the finite-difference time d omain method, we analyze two types of coupled-resonator optical waveguide ( CROW), a coupled-microdisks waveguide and a waveguide composed of coupled d efect cavities in a two-dimensional photonic crystal. We find that the disp ersion relation of the CROW band can be simply described by a small couplin g parameter K, and the spatial characteristics of the CROW modes remain the same as those of the single-resonator high Q modes. As applications of the se unique properties, we demonstrate that CROW's can be utilized in constru cting waveguides without cross talk and enhance the efficiency of second-ha rmonic generation. (C) 2000 Optical Society of America [S0740-3224(00)01303 -5] OCIS codes: 190.2620, 190.4360, 230.7370, 130.2790.