Network-on-chip (NoC) can improve the performance, power efficiency and scalability of multiprocessor system-on-chip (MPSoC). However, traditional NoCs using metallic interconnects consume significant amount of power to deliver even higher communication bandwidth required in the near future. Optical NoCs are based on CMOS-compatible optical waveguides and microresonators, it promise significant bandwidth and power advantages. Due to the difficulties in buffering and processing an optical signal, an electronic control network is used in order to maintain an optical path for point-to-point optical communication....[ Read more ]

Network-on-chip (NoC) can improve the performance, power efficiency and scalability of multiprocessor system-on-chip (MPSoC). However, traditional NoCs using metallic interconnects consume significant amount of power to deliver even higher communication bandwidth required in the near future. Optical NoCs are based on CMOS-compatible optical waveguides and microresonators, it promise significant bandwidth and power advantages. Due to the difficulties in buffering and processing an optical signal, an electronic control network is used in order to maintain an optical path for point-to-point optical communication.

A hybrid optical-electronic mesh NoC, HOME, is proposed which utilizes optical waveguides as well as metallic interconnects in a hierarchical manner. HOME uses hybrid optical-electronic routers for electronic wormhole switching in local networks and optical circuit switching in the global network. Packets transmit in the local network only involve a local electronic switching fabric, which minimizes the number of optical and electronic components involved and significantly reduces both power consumption and latency. For the long-distance communications among different clusters, optical circuit switching is used to achieve a high bandwidth and low delay transmission with low power consumption. HOME also employs a new set of protocols which improve the optical network throughput and reduce latency.

HOME is compared with a matched optical mesh NoC for a 64-core MPSoC in 45nm, using SPICE simulations and our cycle-accurate multi-objective NoC simulation platform, MoLab. Simulation results show that HOME uses 75% less optical/electronic interfaces and laser diodes, and consumes 54% less power, while achieving 65% higher throughput and 64% less latency with a packet size of 64 bytes under 62% inter-cluster traffic.