Ultra-compact directional couplers and race-track microcavity resonators as building blocks for WDM devices

We have designed, fabricated and demonstrated ultra-compact directional couplers (<30 /spl mu/m) and "race-track" micro-resonators as nano-photonic building blocks for a range of WDM devices, including ultra-compact directional couplers, channel-dropping filters, 1/spl times/N demultiplexers and 2/spl times/2 crossbar switches.