Petabit Energy Aware Capacity Enhancement (PEACE)

正如《华尔街日报》最近所讨论的那样，互联网的巨大成功可能要归功于看不见的地下和海底光纤电缆的巨大容量以及与之相关的技术。事实上，20世纪90年代中期网络使用的最初激增与第一个光学放大跨大西洋电缆网络TAT 12/13的投入使用相吻合，该网络允许随时访问否则无法访问的信息。自那时以来，随着波分复用技术的引入，已经取得了巨大的进展，在波分复用技术中，使用多种颜色的光通过同一光纤和相干检测建立独立的连接，这种先进的无线电接收器的光学模拟能够同时检测幅度和频率（或相位）调制，从而使信息承载能力增加一倍，并降低所需的信号功率。为了管理成本，通信网络通常将许多用户之间的连接聚合到网络核心内的单个通信链路上，从而避免了与跨越巨大距离的所有用户的专用链路相关联的巨大成本。通常，成本和可靠性之间的权衡导致来自几千个客户的业务被聚集到单个光纤上，从而导致每波长信道100 Gbit/s的比特率以支持大约10 Mbit/s的宽带连接。然而，这导致光纤中的强度比地球大气层表面的太阳光大一百万倍，因此信号因非线性而显著失真（类似于过载负载扬声器的效果）。这种扭曲限制了光纤链路上传输的最大信息量，除非加以克服，否则这种非线性响应将导致容量紧缩，将互联网接入限制在今天的水平。该项目旨在继续增加支撑现代通信的光纤网络的带宽，包括1760万英国移动的互联网连接和70%的家庭宽带连接渗透率。为了增加容量，我们将最大限度地利用频谱，通过调整移动的电话中的技术用于光纤网络，解决与使用数字和模拟电子和光学处理的平衡以1，000，000倍的带宽处理数据相关的重大问题。这将降低与产生每波长Tb/s容量相关的成本、尺寸和功耗。重要的是，该项目将开发技术来理解和减轻非线性信号失真。非线性失真发生在信道内、信道之间以及每个信道之间，并且噪声起源于光放大器。通过在链路中间沿着变换信号，我们将利用光纤链路的后半部分的非线性响应来消除前半部分的非线性失真，以最小化与信道本身相关联的非线性失真的影响，并优化系统的配置以最小化与噪声的非线性相互作用，导致光纤系统的最大容量的数量级增加。

As recently discussed by the Wall Street Journal, the remarkable success of the internet may be attributed to the tremendous capacity of unseen underground and undersea optical fibre cables and the technologies associated with them. Indeed, the initial surge in web usage in the mid 1990s coincides with the commissioning of the first optically amplified transatlantic cable network, TAT12/13 allowing ready access to information otherwise inaccessible. Tremendous progress has been made since then, with the introduction of wavelength division multiplexing, where multiple colours of light are used to establish independent connections through the same fibre and coherent detection, the optical analogue of an advanced radio receiver able to detect both amplitude and frequency (or phase) modulation simultaneously enabling the information carrying capacity to be doubled and the required signal power to be reduced. To manage the costs, communication networks typically aggregate connections between many users onto a single communications link within the core of the network, avoiding the tremendous costs associated with dedicated links for all users across vast distances. Typically the trade of between cost and reliability has resulted in traffic from several thousand customers being aggregated onto a single fibre resulting in bit rates in the region of 100 Gbit/s per wavelength channel to support broadband connections of around 10 Mbit/s. However, this has resulted in intensities in optical fibres that are a million times greater than sunlight at the surface of the Earth's atmosphere and so the signal is significantly distorted by nonlinearly (a similar effect to overdriving load speakers). This distortion limits the maximum amount of information which may be transmitted across and optical fibre link, and unless combated, the nonlinear response will result in a capacity crunch, limiting access to the internet to today's levels.This project aims to allow the continued increase of the bandwidth of these fibre networks underpinning modern communications, including 17.6 million UK mobile internet connections and 70% penetration of home broadband connections. To increase capacity we will maximise spectral use, by adapting techniques found in mobile phones for use in fibre networks, resolving the significant issues associated with processing data with 1,000,000 times greater bandwidth using a balance of digital and analogue electronic and optical processing. This will reduce cost, size and power consumption associated with producing Tb/s capacities per wavelength. Critically, the project will develop techniques to understand and mitigate the nonlinear signal distortions. Nonlinear distortions occur within a channel, between channels and between each channels and noise originating in the optical amplifiers. By transforming the signal mid way along the link, we will exploit the nonlinear response of the second half of the fibre link to cancel the nonlinear distortion of the first to minimise the impact of nonlinear distortion associated with the channels themselves, and optimise the configuration of the system to minimise the nonlinear interaction with the noise, resulting in orders of magnitude increases in the maximum capacity of the optical fibre system.