Light: A Scalable and Efficient Wavelength-Routed Optical Networks-On-Chip Topology

ABSTRACTWavelength-routed optical networks-on-chip (WRONoCs) are known for delivering collision- and arbitration-free on-chip communication in many-cores systems. While appealing for low latency and high predictability, WRONoCs are challenged by scalability concerns due to two reasons: (1) State-of-the-art WRONoC topologies use a large number of microring resonators (MRRs) which result in much MRR tuning power and crosstalk noise. (2) The positions of master and slave nodes in current topologies do not match realistic layout constraints. Thus, many additional waveguide crossings will be introduced during physical implementation, which degrades the network performance. In this work, we propose an N x (N - 1) WRONoC topology: Light with a 4 x 3 router Hash as the basic building block, and a simple but efficient approach to configure the resonant wavelength for each MRR. Experimental results show that Light outperforms state-of-the-art topologies in terms of enhancing signal-to-noise ratio (SNR) and reducing insertion loss, especially for large-scale networks. Furthermore, Light can be easily implemented onto a physical plane without causing external waveguide crossings.