Next-Generation Optically-Interconnected High-Performance Data Centers

Abstract

Abstract-The communication requirements imposed by the unabated growth in both the size and computational density of modern data centers will soon outpace the fundamental capabilities of conventional electronic interconnection networks. Optical interconnects represent a potentially disruptive technology that can simultaneously satisfy the throughput, latency, and energy demands of these next-generation systems. In this paper, we propose an end-to-end photonic networking platform for future optically-interconnected data center networks. A reconfigurable hybrid photonic network building block and a protocol-agnostic optical network interface comprise the key elements of our proposed system. A modular optical switch fabric prototyping platform is designed and implemented to support a wide variety of potential photonic technologies. We successfully demonstrate nanosecond-scale optical packet-switching at 1-Tb/s per port (40-Gb/s s) through our prototype, configured as a 4 4 switch, and confirm error-free transmission across all wavelengths. In order to flexibly allocate appropriate bandwidth for heterogeneous applications, we further implement and evaluate a novel wavelength-reconfigurable optical packet-and circuit-switch by utilizing our optical switch platform. Finally, we detail our implementation of an optical network interface card (O-NIC) designed to bridge the gap between the well-established protocol layers utilized in current networks and the physical layer of the proposed photonic networks and demonstrate its functionality by the streaming of high-definition video through the end-to-end optical network.

Optical Switching in Next Generation Data Centers

“…Electronic links and switches in the conventional data center design do not leave much space for improvement in this area as they are power hungry devices especially as the bit rate increases. The power consumption of a single switch located in higher data center network tiers can exceed tens of kilowatts when also considering the dedicated cooling systems required [18].…”

“…• Low power consumption: Low power consumption is one of the major characteristics of optical links and switches [18,[23][24][25]. The low loss of optical fibers (around 0.2 dB/km) makes it feasible to set up very long links without the need for regeneration.…”

“…Quantum dot (QD) lasers require very low driving current and offer wide temperature stability, thus eliminating the need for expensive and power-hungry thermo-electric coolers and control circuits. In summary, it is expected that integrated WDM technology, novel laser sources, and volume manufacturing based on emerging technologies such as silicon nanophotonics would result in drastic cost reductions in future optical data center networks [18,47].…”

“…While data center network traffic is essentially unpredictable due to application heterogeneity, communication patterns where only a few ToR switches are tightly coupled with long, extended data flows have been observed in data centers [10,18]. The characteristics of many data center workloads suggest that many applications may not need full bisection bandwidth at the packet granularity.…”

Simultaneous wavelength and orbital angular momentum demultiplexing using tunable MEMS-based Fabry-Perot filter

“…We consider this compact, on-chip integrable device to be especially useful for communication applications, where the distances are relatively short but high data rates are desirable, such as metro-access networks [19,35] and optical interconnects for data centers [36,37].…”