A 1024-Port Optical Uni- and Multicast Packet Switch Fabric

Novel Data Center (DC) architectures based on resource disaggregation hold the potential to increase the resource utilization at a reduced energy and cost envelope, imposing, however, significant challenges in the underlying DC network infrastructure that has to provide high-radix and high-bandwidth connectivity, while maintaining sub-μs latency. At the same time, the explosive growth of AI applications has transformed the traffic profiles on the majority of DC workloads calling for support of advanced network functionalities, such as multicasting. In this direction, we scale-up the Hipoλaos optical packet switch architecture to a thousand-port layout, at the same time upgrading its functionality to allow latency-free intra-tray multicasting. The feasibility of a 10.24-Tb/s capacity switch fabric with a 10-Gb/s line rate in a 1024-port configuration, with four-packet buffering capacity is experimentally demonstrated, revealing error-free performance with <3.4-dB power penalty. Optical multicasting to up-to five nodes is also experimentally validated at 10 Gb/s, with a power penalty variation of less than 1 dB between the different output ports, while multicast operation across the whole required spectral range of a 1024-port switch is investigated, utilizing pairs of wavelengths with different channel spacing. Network-level analysis of the 1024-port Hipoλaos switch revealed sub-μs p90-latency and ∼85% throughput, for the unicast case, when utilizing a two-packet-buffer design. Finally, the simulation model was extended to support the Hipoλaos multicast friendly layout, revealing up to 4250% throughput improvement, as compared to the conventional layout, while maintaining sub-μs latency.