A photonic front-end processor in a WDM ATM multicast switch

Dense wavelength-division multiplexing (DWDM) technology has provided treme ndous transmission capacity in optical fiber communications. However, switc hing and routing capacity is still far behind transmission capacity. This i s because most of today's packet switches and routers are implemented using electronic technologies. Optical packet switches are the potential candida te to boost switching capacity to be comparable with transmission capacity. In this paper, we present a photonic asynchronous transfer mode (ATM) fron t-end processor that has been implemented and is to be used in an optically transparent WDM ATM Multicast (3M) switch. We have successfully demonstrat e the front-end processor in two different experiments, One performs cell d elineation based on ITU standards and overwrites VCI/VPI optically at 2.5 G b/s. The other performs cell synchronization, where cells from different in put ports running at 2.5 Gb/s are phase-aligned in the optical domain befor e they are routed in the switch fabric. The resolution of alignment is achi eved to the extent of 100 ps (or 1/4 bit). An integrated 1 x 2 Y-junction s emiconductor optical amplifier (SOA) switch has been developed to facilitat e the cell synchronizer.