Energy-efficient optical packet switch with recirculating fiber delay line buffers for data center interconnects

Potentially, optical packet switching architectures can alleviate the power consumption, bandwidth and connectivity constraints that existing electronically-switched networks are encountering as interconnects in Data centers and High Performance Computing (HPC) platforms scale out to many thousands of processing nodes. In this paper, we propose a novel optical packet switch architecture, based on the Arrayed Waveguide Grating Router (AWGR), which requires many less tunable wavelength converters than wavelength channels and where contention is efficiently resolved using a low-power re-circulating optical delay module. Compared to previous schemes which propose using an electronic buffer to resolve packet contentions in this type of architecture, we show through simulation that our scheme can improve scalability, by reducing switch power consumption by up to 50% while maintaining low packet latencies. By proper integration of the buffer into the switch and correct dimensioning of the optical buffers, packet loss rates of <; 10^-10 are achievable.