Opportunities and Challenges of Using Plasmonic Components in Nanophotonic Architectures

Nanophotonic architectures have recently been proposed as a path to providing low latency, high bandwidth network-on-chips. These proposals have primarily been based on micro-ring resonator modulators which, while capable of operating at tremendous speed, are known to have both a high manufacturing induced variability and a high degree of temperature dependence. The most common solution to these two problems is to introduce small heaters to control the temperature of the ring directly, which can significantly reduce overall power efficiency. In this paper, we introduce plasmonics as a complementary technology. While plasmonic devices have several important advantages, they come with their own new set of restrictions, including propagation loss and lack of wave division multiplexing (WDM) support. To overcome these challenges we propose a new hybrid photonic/plasmonic channel that can support WDM through the use of photonic micro-ring resonators as variation tolerant passive filters. Our aim is to exploit the best of both technologies: wave-guiding of photonics, and modulating using plasmonics. This channel provides moderate bandwidth with distance independent power consumption and a higher degree of temperature and process variation tolerance. We describe the state of plasmonics research, present architecturally-useful models of many of the most important devices, explore new ways in which the limitations of the technology can most readily be minimized, and quantify the applicability of these novel hybrid schemes across a variety of interconnect strategies. Our link-level analysis shows that the hybrid channel can save from 28% to 45% of total channel energy-cost per bit depending on process variation conditions.