Physical Layer scalability of WDM optical packet interconnection networks

The physical layer scalability of a packet-switched optical interconnection network utilizing semiconductor optical amplifier (SOA) switch elements is investigated experimentally and with numerical modeling. Optical packets containing payloads of multiple wavelength-division-multiplexing (WDM) channels are propagated through cascaded SOA-based switching nodes in a recirculating test-bed environment. Experiments show that bit-error rates (BERs) below 10^-9 can be maintained through 58 switching nodes for the entire eight-channel 10-Gb/s-per-channel payload distributed over 24.2 nm of the C-band. When the packet payload consists of a single 10-Gb/s channel, 98 node hops can be traversed before a BER of 10^-9 is exceeded. In conjunction with the experiments, a novel phenomenological modeling technique is developed in order to forecast the scalability of SOA-based WDM packet interconnection networks. This technique is shown to yield results that correlate well with the experimental data. These investigations are presented as predictors of the physical limitations of large-scale WDM packet-switched networks.