Multiwavelength-channel header recognition for reconfigurable WDM networks using optical correlators based on sampled fiber Bragg gratings

We demonstrate a tunable, multiwavelength optical correlator that uses an array of sampled fiber Bragg gratings (FBGs) as the correlating element. The incoming wavelength-division-multiplexing (WDM) data streams are tapped off and the packet headers on each 10-Gb/s channel are simultaneously recognized and correlated to a reconfigurable header code. The correlation output for each channel is compared to a threshold level, and simple decision electronics are used to drive a set of switches to route the individual WDM packets accordingly. Using this technique, we recognize two WDM 10-Gb/s packet headers simultaneously, with a negligible power penalty when switching packets to the appropriate output port. Moreover, we tune the gratings for reconfigurable routing.