Theses Doctoral

Photonic Switches and Networks for High-Performance Computing and Data Centers

Wang, Howard

The accelerated growth in performance of microprocessors and the emergence of chip multiprocessors, which are now widely leveraged in current data centers and high-performance computing (HPC) systems, have motivated the need for developing novel interconnection networks solutions to meet the growing need for data transmissions across all levels of the infrastructure. This work posits that, given the unique characteristics of optics---advantages and limitations---purpose-driven systems-level designs are necessary in order to harness the tremendous performance and efficiency opportunities that can be enabled by photonic interconnects. First, an enhanced optically connected network architecture is presented featuring advanced photonic functionalities to support a wider class of bandwidth-intensive traffic patterns characteristic of cloud computing systems. This proposed architectural framework can enable a rich set of photonic resources to be allocated on-demand to optimize communications between various applications within the data center. A prototype of the proposed optical network architecture is constructed and a demonstration of two unique functionalities, serving to validate the physical layer feasibility of the system, is presented. An instantiation of this architectural framework is presented that enables physical layer data duplication in order to more effectively support reliable group data delivery in the data center. Compared to the conventional solutions that duplicate data in the network or application layer, this architecture achieves efficient data transmission over the ultra-fast, loss-free, energy-efficient and low cost optical paths, with simplified flow control, congestion control, and group membership management. Both an end-to-end hardware experiment and large-scale simulations were carried out to evaluate the efficacy of the design. Next, the challenges associated with interfacing to photonically-switched networks are explored. In particular, various interface designs aimed at addressing the unique challenges imposed by optical-packet switched networks are proposed and evaluated. First, an overview of the data vortex network optical packet switch architecture is given. A high-speed optical packet formatter and interface is then presented along with the results of end-to-end data exchanges across the interface connected to a data vortex network. Finally, the design of a low-power all-optical interface alternative is validated with an end-to-end demonstration. Finally, various unique photonic switching node designs are introduced for a variety of applications|a nanosecond-scale bidirectional 2 x —2 switch to construct efficient optical fat-tree architectures, a 4 x —4 switch capable of operating as both a nanosecond-scale optical packet switch and as an optical circuit switch, and a non-blocking 4 x —4 switch designed for constructing on-chip photonic integrated networks.


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More About This Work

Academic Units
Electrical Engineering
Thesis Advisors
Bergman, Keren
Ph.D., Columbia University
Published Here
April 17, 2015