Multinode demonstration of a multihop wavelength-routed all-optical packet-switched network

We present an experimental demonstration of a multinode WDM multihop packet network interconnected with an arrayed-waveguide router. Each node has the full functionality to route packets with subcarrier multiplexed headers and perform fast wavelength translation between four wavelengths and space switching between a local host and an 8×8 waveguide-grating array router. Packets consist of a 3050 bit payload at 2.5 Gbps and a 122-bit NRZ header at 100 Mbps multiplexed on a 3-GHz subcarrier. Our demonstration incorporates several new performance enhancing subsystems, which previous demonstrations lacked. These enhancements include fast, uniform wavelength-conversion-switching performed using a novel current injection circuit in combination with a four-section wavelength tunable GCSR laser yielding wavelength switching times under 4 ns for all wavelengths required by the node. Simultaneous wavelength conversion of subcarrier multiplexed packet headers and baseband payload via cross gain saturation in semiconductor optical amplifiers is shown to preserve the header through multiple all-optical hops. We have also implemented a different header recovery technique on each node: coherent RF heterodyning on one node and incoherent RF detection using a fast Schottky barrier diode on the other