FTTDOR: Microring Fault-resilient Optical Router for Reliable Optical Network-on-Chip Systems

Photonic Networks-on-Chip (PNoCs) have been proposed as a disruptive technology solution to the silicon problem showing their great superiority over their electronic counterparts. In these architectures, higher bandwidth can be achieved thanks to the light speed transmissions, and the power required to transmit over a distance is much lower. Despite these advantages, PNoC designs are very complex, and thus are more susceptible to physical defects and short-term malfunctions. Therefore, fault-tolerance has become a primordial requirement for these future generation high-performance systems. In this paper, we present a fault-tolerant optical router, named FTTDOR, with its electrical control module for highlyreliable low-power 3D-Networks-on-Chip (PHENIC). It uses minimal redundancy to assure accuracy of the packet transmission even after faulty Microring Resonators (MRs) are detected. The fault-tolerant optical switch is decomposed nonblocking, with minimal MRs, and requires no MRs for straight transmission (East to West, North to South, and Up to Down, as well as their inverses). Simulation results show that the network can maintain 98% and 94% throughput when considering 3% and 20% fault-rates, respectively. These results come with 35% decrease in the number of MRs when compared to the conventional crossbar switch resulting in 32% power reduction.