# HyPPI NoC: Bringing Hybrid Plasmonics to an Opto-Electronic Network-on-Chip

## TL;DR

This paper introduces HyPPI, a hybrid plasmonic-photonic interconnect for network-on-chip designs, demonstrating significant performance and efficiency improvements over traditional nanophotonics and electronics.

## Contribution

It proposes and analyzes a novel hybrid plasmonic-photonic interconnect, HyPPI, for opto-electronic NoCs, showing its advantages in performance, energy, and area efficiency.

## Key findings

- Augmenting electronic NoCs with HyPPI improves performance-to-cost ratio by up to 1.8x.
- Trace-based simulations show latency improvements up to 1.64x with negligible energy increase.
- Futuristic projections indicate HyPPI-based NoCs are two orders more energy and area efficient than alternatives.

## Abstract

As we move towards an era of hundreds of cores, the research community has witnessed the emergence of opto-electronic network on-chip designs based on nanophotonics, in order to achieve higher network throughput, lower latencies, and lower dynamic power. However, traditional nanophotonics options face limitations such as large device footprints compared with electronics, higher static power due to continuous laser operation, and an upper limit on achievable data rates due to large device capacitances. Nanoplasmonics is an emerging technology that has the potential for providing transformative gains on multiple metrics due to its potential to increase the light-matter interaction. In this paper, we propose and analyze a hybrid opto-electric NoC that incorporates Hybrid Plasmonics Photonics Interconnect (HyPPI), an optical interconnect that combines photonics with plasmonics. We explore various opto-electronic network hybridization options by augmenting a mesh network with HyPPI links, and compare them with the equivalent options afforded by conventional nanophotonics as well as pure electronics. Our design space exploration indicates that augmenting an electronic NoC with HyPPI gives a performance to cost ratio improvement of up to 1.8x. To further validate our estimates, we conduct trace based simulations using the NAS Parallel Benchmark suite. These benchmarks show latency improvements up to 1.64x, with negligible energy increase. We then further carry out performance and cost projections for fully optical NoCs, using HyPPI as well as conventional nanophotonics. These futuristic projections indicate that all-HyPPI NoCs would be two orders more energy efficient than electronics, and two orders more area efficient than all-photonic NoCs.