A Highly Scalable Optical Network-on-Chip with Small Network Diameter and Deadlock Freedom

To increase the performance of chip multiprocessors, optical network-on-chip (ONoC) becomes promising because of its high bandwidth and low energy consumption. In this paper, we propose an architecture called RPNoC (Ring-based Packet-switched NoC), which uses few optical devices. Specifically, Single-waveguide RPNoC employs only one waveguide. Multiwaveguide RPNoC introduces space division multiplexing to make the architecture highly scalable. A novel wavelength assignment method and a deadlock-free deterministic routing algorithm are jointly designed, which make the network diameter quite small. This design also guarantees deadlock freedom, a little resource use, and low complexity at the same time. Evaluation is carried out for the 64-node RPNoC under different synthetic and realistic traffic patterns. The simulation result shows that it yields high throughput and low latency. Comparison with other packet-switched ONoCs shows that RPNoC has the lowest energy consumption.