RobustONoC: Fault-Tolerant Optical Networks-on-Chip with Path Backup and Signal Reflection

Optical networks-on-chips (ONoCs) have become a potential solution for on-chip communication of multi- and many-core systems. Compared to electrical NoCs, they provide superior communication bandwidth, efficiency in power consumption, and low latency. Prior studies on this topic have focused on developing efficient architectures of optical routers based on micro-ring resonators (MRRs). However, potential transmission faults of MRRs after manufacturing have not yet been considered in architecture design of ONoCs. To enhance the reliability of ONoCs, we propose a framework to construct backup optical paths with wavelength reflection. To minimize power consumption and resource usage, the proposed framework takes advantage of the multi-wavelength resonance property of MRRs, an important feature of MRRs which has rarely been considered in previous studies. With these concepts, the architectures of ONoCs are enhanced by a modified random search algorithm to achieve fault tolerance. Experimental results demonstrate that all single faults in ONoCs can be dealt with effectively, while the number of backup MRRs can be reduced effectively.