Exploring hybrid photonic networks-on-chip foremerging chip multiprocessors

Increasing application complexity and improvements in process technology have today enabled chip multiprocessors (CMPs) with tens to hundreds of cores on a chip. Networks on Chip (NoCs) have emerged as scalable communication fabrics that can support high bandwidths for these massively parallel systems. However, traditional electrical NoC implementations still need to overcome the challenges of high data transfer latencies and large power consumption. On-chip photonic interconnects have recently been proposed as an alternative to address these challenges, with high performance-per-watt characteristics for intra-chip communication. In this paper, we explore using photonic interconnects on a chip to enhance traditional electrical NoCs. Our proposed hybrid photonic NoC utilizes a photonic ring waveguide to enhance a traditional 2D electrical mesh NoC. Experimental results indicate a strong motivation for considering the proposed hybrid photonic NoC for future CMPs -- as much as a 13× reduction in power consumption and improved throughput and access latencies, compared to traditional electrical 2D mesh and torus NoC architectures.