Energy Efficiency Analysis of Comb Source Carrier-Injection Ring-Based Silicon Photonic Link

Current electronic interconnections in high performance computing (HPC) systems are reaching their limit in supporting high data traffic demands. Dense wavelength-division multiplexed (DWDM) links have gained interest as they can potentially alleviate these interconnect bandwidth demands while also lowering the cost and energy consumption compared to traditional electronic links. In this article we present an analysis of a ring-based DWDM silicon photonic (SiP) link architecture with a comb laser source and p-i-n photodetectors. Specifically, we consider microring resonators (MRRs) with narrow bus waveguides and carrier-injection ring modulators. We propose a new method to select the optimal comb source setting to minimize the laser power consumption at a particular data rate. Additionally, we leverage power penalty models supported by measurements to estimate the effective received optical power at the receiver input of each of the DWDM channels which yields a bit error rate (BER) of 10^-12 or lower. We show that the analyzed comb source has the lowest power consumption per channel for 24 consecutive lines. For these comb settings, the maximum channel data rate of non-return to zero on-off keying (NRZ-OOK) signals is 22 Gbps, and the minimum energy consumption is 3.28 pj/bit.