Ultrafast Forwarding Architecture Using a Single Optical Processor for Multiple SAC-Label Recognition Based on FWM

We propose and demonstrate a novel ultrafast label processor that can recognize multiple spectral amplitude coded (SAC) labels using four wave mixing (FWM) sideband allocation and selective optical filtering. Our proposed solution favors hardware simplicity over bandwidth efficiency in order to achieve ultrafast label recognition at reasonable cost. Our implementation, unlike all other optical label processing techniques, does not require time gating, envelope detectors, or serial-to-parallel converters. Labels are transmitted simultaneously with the payload, improving temporal efficiency at the expense of spectral efficiency. Note that bandwidth efficiency can be improved through a frequency management scheme that uses irregular spacing of wavelengths for payload and label, a complexity overhead in management similar to that in long-haul networks employing irregular spacing of carriers to avoid FWM products. We present two experiments of the single processor for ultrafast forwarding using first optoelectronic and then all-optical switches. In the first experiment, we use 10 SAC labels with minimum bin separation of 25 GHz, 10 Gb/s variable-length data packets, and forward packets over 200 km using electrooptical switches. In the second experiment, all-optical switching at 40 Gb/s is demonstrated using a SAC family for up to 36 labels. We present details on the families of spectral codes for label recognition, using unequally spaced frequency bins. A code family with weight 2 and length 9 uniquely identifies 36 labels. Hardware complexity is moderate compared with short-pulse code labels (mode-locked laser) techniques. Two stable tunable lasers are required for label generation of this code family; all other hardware is commercial, off-the-shelf components such as semiconductor optical amplifiers, array waveguide gratings, optoelectronic switches, and photodetectors.