ODOR: a microresonator-based high-performance low-cost router for optical networks-on-Chip

The performance of system-on-chip is determined not only by the performance of its functional units, but also by how efficiently they cooperate with one another. It is the on-chip communication architecture which determines the cooperation efficiency. Network-on-Chip (NoC) is introduced to improve communication bandwidth and power efficiency. However, traditional metallic interconnects consume significant amount of power to deliver large communication bandwidths. Optical NoCs are based on silicon optical interconnects with significant bandwidth and power advantages. Optical routers are the key enabling components of optical NoCs. This paper proposed a novel optical router architecture, ODOR, for optical NoCs based on XY routing algorithm. We compared ODOR with four other router architectures, and analyzed three aspects in details, including power consumption, optical power insertion loss, and the number of microresonators. The results show that ODOR has the lowest power consumption and losses and requires the least microresonators. ODOR has 40% less power consumption, 40% less loss, and 52% less microresonator than the full-connected crossbar. Furthermore, ODOR has a special feature which guarantees the maximum power to route a packet through a network to be a small constant number, regardless of the network size. The maximum power consumption is 0.96fJ/bit under current technology. We simulated a 6x6 2D mesh NoC based on ODOR, and showed the end-to-end delay and network throughput under different offered loads and packet sizes.