25Gb/s 3.6pJ/b and 15Gb/s 1.37pJ/b VCSEL-Based Optical Links in 90nm CMOS

📋 论文概要

本文在90nm CMOS工艺中实现了两种基于VCSEL的多模光纤光链路，分别达到25Gb/s 3.6pJ/b和15Gb/s 1.37pJ/b的能效，解决了高性能计算系统对亚2pJ/bit能效光互连的需求。通过共享发射机并采用两种不同接收机，探索了功耗、带宽和面积之间的权衡。

💡 主要创新点

• 实现了15-22Gb/s范围内低于2pJ/bit的能效，突破了此前报道的≥2.5pJ/bit水平。
• 采用两种不同接收机设计，分别优化高速率（25Gb/s）和低功耗（15Gb/s）场景，展示了灵活的功耗/带宽/面积权衡。

🏷 关键词

📄 原文摘要

Future high-performance computing systems require sub-2pJ/bit power efficiencies at >10Gb/s [1-2]. The best reported optical link efficiencies at these data rates are ≥2.5pJ/bit [1-4]. This paper describes two VCSEL-based multimode (MM) fiber optical links achieving sub-2pJ/bit power efficiency from 15Gb/s to 22Gb/s. The links realized in 90nm CMOS share the same TX but use two different RXs that explore different aspects of the power/BW/area tradeoff. The system-level block diagram of the optical link and the TX circuits are shown in Fig. 24.5.1. The laser diode driver (LDD) TX consists of a 2-stage preamplifier and a main driver stage (DRV). The preamplifier stages are Cherry-Hooper (CH) amplifiers with 1.6V supply VDD_PA. The DRV is an inductively-peaked differential amplifier, one side wire-bonded to a 5µm diameter 850nm GaAs laser diode (VCSEL) [5] and the other side terminated to 60Ω on chip. The DRV is

👥 作者与机构

Jonathan Proesel, Clint Schow, Alexander Rylyakov

IBM T. J. Watson, Yorktown Heights, NY