Theory of coupled photonic crystal for both synchronous as well as asynchronous waveguided systems is presented. Techniques for analyzing symmetric (even) and anti-symmetric (odd) polarized modes in coupled photonic crystals waveguides are presented. Techniques used include plane wave expansion method (PWM) and finite difference time domain (FDTD). Results obtained from both techniques are shown to be in good agreement. Applications presented include, frequency selective filter, splitter, and switch.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.