Rethinking the fundamentals of photonic signal processing for "green" communications and computing

在信息和通信技术(ICT)系统中实现用于时间信号产生、处理和检测的光子电路通常被认为是克服当前基于电子的解决方案的速度限制的一种非常有前途的方法。光子学的带宽优势尤其具有吸引力，以应对高速电信、信息处理和计算平台中不断增长的“以更低的成本获得更高容量”的需求。然而，光子解决方案仍然受到两个主要限制，即1)它们通常很笨重，2)它们“耗电”，阻碍了光子信号处理技术的实际使用和推广，超出了一些利基应用。通过在紧凑型光纤技术(例如光纤布拉格光栅)或集成波导配置(最突出的是与cmos兼容的光子芯片)中成功地实现器件，在减小光子结构尺寸方面已经取得了重大进展。这种占地面积的改进反过来又对光子信号处理技术的能量性能产生了积极影响。尽管取得了这一进展，但目前的光子信号处理设计本质上比竞争对手的技术(如电子学)使用的能量要高得多，到目前为止，很少有人致力于提高其能效方面的性能。**本提案中描述的研究计划将重点放在设计和实现光子信号处理设备，以有效地产生、处理和检测超高速数据和控制信号，这对宽带电信以及高速信息处理和计算至关重要。该计划的独特重点将是定义创新的、通用的策略，以优化目标光子电路的能效，而不牺牲它们的处理速度优势。特别是，我们将在光纤和/或集成波导(硅光子学)技术中追求目标电路的实现，重点是光纤/集成光栅结构。将要研究的新设计策略将能够在处理速度远远超出电子设备的范围、高于THz范围的情况下，在当前技术的基础上提供显著(数量级)的能量性能改进。在中长期内要追求的子系统将包括用于光学线性滤波、任意光波形产生和检测以及超高速模拟和数字计算的“片上”可重构电路。在短期内，该计划的核心活动将围绕四个相互关联的研究项目进行，涉及开发(A)能量优化的模拟光信号处理器，(B)“绿色”无噪声波形放大方法，(C)“零能量”超快光逻辑门，以及(D)用于超快时钟恢复、产生和处理的能量优化电路。**这项研究的结果可为在更大范围内使用光子信号处理解决方案开辟道路，直接有助于克服目前几乎任何依赖信通技术基础设施的应用或部门的电子瓶颈。该计划产生的新知识和在目标战略领域对高素质人员(HQP)的培训将有助于提高加拿大在非常广泛的高科技行业的全球竞争力。

The implementation of photonic circuits for temporal signal generation, processing, and detection in information and communications technology (ICT) systems is generally envisioned as an extremely promising approach to overcome the speed limitations of present electronics-based solutions. The bandwidth advantage of photonics is especially attractive to cope with the ever-increasing demand for "higher capacity at a lower cost" in high-speed telecommunications, information processing and computing platforms. However, photonic solutions still suffer from two main limitations, namely 1) they are typically bulky and 2) they are "power hungry", preventing the practical use and spread of photonic signal-processing technologies beyond a few niche applications. Significant progress has been made concerning size reduction of photonic structures, through successful device implementations in compact fiber-optics technologies, e.g. fiber Bragg gratings, or in integrated-waveguide configurations, most prominently CMOS-compatible photonic chips. Such footprint improvements in turn have had a positive impact on the energy performance of photonic signal-processing technologies. In spite of this progress, present photonic signal-processing designs intrinsically use much higher amounts of energy than competing technologies (e.g. electronics), and very little effort has been devoted so far to improving their performance in terms of energy efficiency. **The research program described in this proposal will focus on the design and realization of photonic signal-processing devices for efficient generation, manipulation, and detection of ultrafast data and control signals, of fundamental importance for broadband telecommunications, and high-speed information processing and computing. The distinctive focus of the program will be on defining innovative, general strategies for optimizing the energy efficiency of the target photonic circuits without trading their processing speed advantage. Particularly, we will pursue the realization of the target circuits in fiber-optics and/or integrated waveguide (silicon photonics) technologies, with an emphasis on fiber/integrated grating structures. The novel design strategies to be investigated will be capable of providing dramatic (orders-of-magnitude) improvements on energy performance over present technologies at processing speeds well beyond the reach of electronics, above the THz range. Sub-systems to be pursued in the mid to long-term will include `on chip' reconfigurable circuits for optical linear filtering, arbitrary optical waveform generation and detection, and ultrafast analog and digital computing. In the short-term, activities at the core of the program will be conducted around four inter-related research projects, involving the development of (a) energy-optimized analog optical signal processors, (b) "green" noiseless waveform amplification methods, (c) "zero-energy" ultrafast optical logical gates, and (d) energy-optimized circuits for ultrafast clock recovery, generation and processing. **The outcome of this research could open the path to the use of photonic signal-processing solutions at a much larger scale, directly contributing to overcome present electronic bottlenecks in almost any application or sector relying in ICT infrastructure. The new knowledge generated from this program and the training of highly qualified personnel (HQP) in the targeted strategic areas will contribute to enhance Canada's global competitiveness across a very wide range of high-technology sectors.