OPSquare: towards petabit/s optical data center networks based on WDM cross-connect switches with flow control

Scaling the capacity while maintaining low latency and power consumption is a challenge for hierarchical data center networks (DCNs) based on electrical switches. In this work we present a novel optical DCN architecture called OPSquare that potentially addresses the scaling issues by employing parallel intra- and inter-cluster switching networks based on distributed fast WDM optical cross-connect (OXC) switches and a novel top-of-rack (ToR) switch architecture. The WDM OXC switches with nanoseconds reconfiguration time allow flexible switching capability in both wavelength and time domains and statistical multiplexing. Packet loss, latency, throughput, multi-path dynamic switching with flow control operation, and scalability will be discussed and experimentally evaluation by employing a 4×4 OXC prototypes. The potential of switching higher-order modulation and waveband signals further proves the suitability of OPSquare architecture for Petabit/s and low-latency DCN by using optical switches with moderate radix.