Optimal interfacing with coupled-cavities slow-light waveguides: mimicking periodic structures with a compact device.

We present an approach for optimal interfacing with coupled resonator optical waveguides (CROWs). The interfacing section constitute an additional small set of cavities with varying coupling coefficients at edges of the CROW in order to match its impedance with that of the I/O waveguides. Efficiencies exceeding 99.9% are shown to be possible over a bandwidth which is larger than 50% of that of the CROW. We study the relations between the number of resonators comprising the interface section and its overall performances.