Petabit Energy Aware Capacity Enhancement (PEACE)

正如《华尔街日报》最近讨论的那样，互联网的显著成功可能要归功于看不见的地下和海底光缆的巨大容量以及与之相关的技术。事实上，1990年代中期网络使用量的最初激增恰逢第一个光放大跨大西洋电缆网络TAT12/13投入使用，使人们可以随时获取否则无法获取的信息。自那时以来，随着波分复用的引入取得了巨大的进步，其中使用多种颜色的光来通过相同的光纤和相干检测建立独立的连接，能够同时检测幅度和频率(或相位)调制的先进无线电接收器的光学模拟使得信息承载能力翻了一番，所需的信号功率被降低。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，从而避免与跨越遥远距离的所有用户的专用链路相关联的巨大成本。通常，在成本和可靠性之间进行权衡，导致来自数千名客户的流量聚合到一根光纤上，导致每个波长通道的比特率约为100Gbit/S，以支持约10Mbit/S的宽带连接。然而，这导致光纤的强度比地球大气层表面的太阳光大一百万倍，因此信号受到非线性的严重失真(类似于超载扬声器的影响)。这种失真限制了可以通过光纤链路传输的最大信息量，除非得到打击，否则这种非线性反应将导致容量紧缩，将互联网接入限制到今天的水平。该项目旨在允许这些支撑现代通信的光纤网络的带宽继续增加，包括1760万英国移动互联网连接和70%的家庭宽带连接普及率。为了增加容量，我们将最大限度地提高频谱利用率，方法是将移动电话中的技术用于光纤网络，使用数字和模拟电子和光学处理的平衡来解决与处理带宽增加1,000,000倍的数据相关的重大问题。这将降低与每波长生产Tb/S容量相关的成本、尺寸和功耗。重要的是，该项目将开发了解和缓解非线性信号失真的技术。非线性失真发生在通道内、通道之间和每个通道之间，以及源自光放大的噪声。通过在链路中途变换信号，我们将利用光纤链路的后半部分的非线性响应来抵消第一部分的非线性失真，以最大限度地减少与通道本身相关的非线性失真的影响，并优化系统配置，以最大限度地减少与噪声的非线性相互作用，从而使光纤系统的最大容量增加数量级。

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.