Performance Requirements for Terabit-Class Silicon Photonic Links Based on Cascaded Microring Resonators

The electrical interconnects in high performance computing (HPC) systems are reaching their bandwidth capacities in supporting data-intensive applications. Currently, communication between compute nodes through these interconnects is the main bottleneck for overall HPC system performance. Optical interconnects based on the emerging silicon photonics (SiP) platform are considered to be a promising replacement to boost the speed of the data transfer with reduced cost and energy consumption compared to electrical interconnects. In this paper, we present a comprehensive analysis of a comb source microring-based SiP link architecture with p-i-n photodetectors. In particular, we direct our focus on improved grating coupler and bus waveguide designs to reduce the link power penalties. Additionally, we map the required performance from the comb laser to provide an aggregated data rate of 1 Tbps under the constraints of free spectral range (FSR) and nonlinearities of the microring resonators (MRRs). We show that a select few comb configurations satisfy these requirements, and energy consumption as low as 3\,\frac{\text{pJ}}{\text{bit}} is achievable.