ORB: An on-chip optical ring bus communication architecture for multi-processor systems-on-chip

As application complexity continues to increase, multiprocessor systems-on-chip (MPSoC) with tens to hundreds of processing cores are becoming the norm. While computational cores have become faster with each successive technology generation, communication between them has become a bottleneck that limits overall chip performance. On-chip optical interconnects can overcome this bottleneck by replacing electrical wires with optical waveguides. In this paper we propose an optical ring bus (ORB) based on-chip communication architecture for next generation MPSoCs. ORB uses an optical ring waveguide to replace global pipelined electrical interconnects while preserving the interface with today's bus protocol standards such as AMBA AXI. We present experiments to show how ORB has the potential to provide superior performance (more than 2times) and significantly lower power consumption (a reduction of more than 10times) compared to traditionally used pipelined, all-electrical bus-based communication architectures, for 65-22 nm technology nodes.