Tailoring the coupling factor and the device length to optimize the frequency response of a photonic crystal add/drop multiplexer

We design an ultra compact add/drop multiplexer by contra-directional coupling two photonic crystal waveguides. We analyse different device configurations and evaluate their performances, evidencing a trade-off between the filter selectivity and the device dimension. The design guidelines for an optimal channel selector are given and a highly selective /spl mu/-sized device is presented, that transmits about 99% of the input power to the drop port.