12.1 terabit/second data center interconnects using O-band coherent transmission with QD-MLL frequency combs

作者：Santiago Bernal, Mario Dumont, Essam Berikaa, Charles St-Arnault, Yixiang Hu, R. Gutiérrez-Castrejón, Weijia Li, Zixian Wei, Benjamin Krueger, Fabio Pittalà, John E. Bowers, David V. Plant · 发表于：Nature Communications · 年份：2024 · DOI：10.1038/s41467-024-51682-2 · 被引用次数：51 · 研究领域：Advanced Fiber Laser Technologies、Optical Network Technologies、Photonic and Optical Devices

Most current Data Center Interconnects (DCI) use intensity modulation direct detection (IMDD) configurations due to their low complexity and cost. However, significant scaling challenges allow coherent solutions to become contenders in these short reach applications. We present an O-band coherent optical fiber transmission system based on Quantum Dot-Mode Locked Lasers (QD-MLLs) using two independent free-running comb lasers, one each for the carrier and the Local Oscillator (LO). Using a comb-to-comb configuration, we demonstrate a 10 km single mode fiber, O-band, coherent, heterodyne, 12.1 Tbps system operating at 0.47 Tbps/λ using 26 λs. We used fewer comb lines (26 λs), faster symbol rate (56 GBaud) and higher constellation cardinality (32 QAM) relative to the highest capacity C-band systems reported to date. Through design, analysis, and experimentation, we quantify the optimum comb line spacing for this use case. We compare potential configurations for increasing data center interconnect capacities whilst reducing power consumption, complexity, and cost.