Heterogeneous space switches for power-efficient optical interconnection networks

Abstract

Space switches are the fundamental elements in single plane and multi-plane optical interconnection networks. This paper proposes a heterogeneous implementation of optical space switches based on two gating elements, amplifiers such as semiconductor optical amplifier (SOA) and modulators such as Mach-Zehnder modulators. The heterogenous implementation has the advantage of being more power-efficient than a homogeneous implementation based only on SOAs and more scalable than a homogeneous implementation based only on modulatorbased gates as the optical power loss can be compensated by the SOAs.The paper derives the requirements in number of gating elements for different space switch architectures (i.e., crossbar, Beneš, Spanke, Clos, Spanke-Beneš, and hybrid Clos). Based on the such derivation, the scalability and the power-efficiency of the different non-blocking architectures with heterogeneous design are assessed, with the aim at identifying the most suitable architecture based on today's available optical technologies. Results show that power saving around 80% are achievable when using a heterogeneous implementation instead of a homogenous SOA-based implementation.

Heterogeneous Optical Space Switches for Scalable and Energy-Efficient Data Centers

“…Instead, in the Spanke-Beneš and crossbar the number of crossed SOAs is much higher and grows linearly with the number of ports, thus severely impairing the scalability, as well as the physical layer performance. In addition, Beneš architecture requires a total number of SOAs and MZIs lower than the other considered architectures [18]. Similar performance in terms of scalability are experienced for different values of and [6], leading to the conclusion that Spanke and Beneš architectures represent the best candidates from the scalability standpoint [18].…”