Transceiver Circuits for Optical Backplanes

光背板收发器电路

• 批准号: RGPIN-2014-04399
• 负责人: Sheikholeslami, Ali
• 金额: $ 1.82万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=587783
• 关键词: Transceiver; Circuits; Optical; Backplanes

Optical links have long been known as lighter, cleaner, and faster alternatives to copper cables for long-haul data communication where the distance between communicating nodes is in kilometers. In the last decade, however, as the sheer weight and volume of the copper cables have increased substantially, optical links have replaced copper cables in communication over shorter distances, such as a few meters between computers in data centers. Today, optical links are competing against copper at distances as short as a few centimeters, such as those between a microprocessor and a memory on a printer circuit board (PCB), for speeds in excess of 25Gb/s. At these speeds, the copper traces attenuate the electrical signal so much that it is extremely hard to recover the correct data at the receiver end no matter how much electronics one includes at the two ends of the link. On the other hand, the attenuation of an optical channel is known to be negligible at these distances even at far higher data rates. What has prohibited so far the wider use of optical backplanes is mainly the cost of electrical to optical and optical to electrical interfaces and the surrounding electronics to compensate for various imperfections of these interfaces. This is in addition to the assembly cost of the chips on board as much more precise alignments are necessary. This proposal relates to the innovation of designs (devices and circuits) for optical/electrical interfaces, and the electronics surrounding these interfaces. In particular, we propose designs for optical devices such as the ring modulators, photo-detectors, and optical filters, and electronic circuits such as trans-impedance amplifiers (TIA), limiting amplifiers, equalizers, and clock and data recovery circuits. The long-term objective of this research is to demonstrate a fully integrated transceiver for optical backplanes. The short-term objectives are to design, fabricate, and test individual building blocks of the complete transceiver. As part of this research, we also develop a system-level model (in Matlab or Simulink) that includes all the building blocks, along with their main sources of non-idealities. This model will be used to identify the link performance as a function of key design parameters. Accordingly, we determine the sensitivity of the link performance to each design parameter in order to identify the performance limits of the architectures. Once we determine the final architecture, we will move towards implementing one block at a time in circuit level. We will test each block individually before moving on to higher levels of integration.

长期以来，光链路一直被认为是铜缆的更轻、更清洁、更快的替代品，用于长距离数据通信，其中通信节点之间的距离以公里为单位。然而，在过去的十年中，随着铜缆的绝对重量和体积大幅增加，光纤链路已经取代了铜缆在更短距离上的通信，例如数据中心计算机之间的几米。如今，光链路在短至几厘米的距离上与铜线竞争，例如打印机电路板（PCB）上的微处理器和存储器之间的距离，速度超过25 Gb/s。在这些速度下，铜迹线使电信号衰减得如此之大，以至于无论在链路的两端包括多少电子设备，都很难在接收器端恢复正确的数据。另一方面，已知光信道的衰减在这些距离处甚至在高得多的数据速率下是可忽略的。到目前为止，阻碍光学背板更广泛使用的主要是电到光和光到电接口以及周围电子设备的成本，以补偿这些接口的各种缺陷。这除了板上芯片的组装成本之外，因为需要更精确的对准。 该提案涉及光/电接口的设计（设备和电路）以及围绕这些接口的电子设备的创新。特别是，我们提出了设计的光学器件，如环形调制器，光电探测器和光学滤波器，和电子电路，如跨阻放大器（TIA），限幅放大器，均衡器，时钟和数据恢复电路。这项研究的长期目标是展示一个完全集成的光背板收发器。短期目标是设计、制造和测试完整收发器的各个构建模块。 作为这项研究的一部分，我们还开发了一个系统级模型（在Matlab或Simulink中），其中包括所有的构建块，沿着其主要来源的非理想性。该模型将被用来确定作为关键设计参数的函数的链路性能。因此，我们确定每个设计参数的链路性能的灵敏度，以确定的架构的性能限制。一旦我们确定了最终的架构，我们将朝着在电路级一次实现一个模块的方向发展。我们将在进入更高级别的集成之前单独测试每个块。