Extremely Wideband Optical Fibre Communication Systems

高清视频流、云计算、人工智能、大数据和物联网等带宽密集型互联网服务的使用呈指数级增长，要求光数据传输技术取得新进展，以实现超高吞吐量和最小延迟。超越当前的信道限制可以说是数字光通信面临的最大挑战。为了实现这一目标，拟议的研究计划将开发新的方法，以显著提高未来通信系统的容量，重点是超宽带光传输和放大，结合自适应编码调制和数字信号处理，以确保未来强大的通信基础设施。系统容量受三个维度的限制：带宽、信息谱密度和空间。虽然许多研究都集中在最大化信息频谱密度和研究空分复用上，但对带宽域的关注很少。我们建议使用收发器，宽带光放大器来显着扩展信道带宽，超越完善的掺铒光纤放大器（EDFA），重点关注在拉曼放大辅助下的掺铋和掺铥光纤放大器。再加上基于多根光纤或新的多芯光纤的空分多路复用，将确保未来实现数十pb /s的系统容量。在EWOC研究中，我们将更深入地了解控制这种超宽系统容量上限的基本非线性效应，这是以前从未研究过的。三个主要挑战是：(i)充分利用无处不在的二氧化硅光纤低损耗窗口的带宽，克服单模光纤的限制，达到每核高达250 Tb/s的比特率；（ii）超越拉曼增益位移-意味着在广泛不同的色散和非线性制度中，相关的非线性信号对信号的干扰必须被理解、量化和有效缓解；（iii）实验证明，在各种距离和比特率传输场景和核心应用中，显著增加的带宽与新型编码调制、先进的DSP和非线性缓解相结合；接入和数据中心网络。EWOC提案是由UCL的光网络集团和南安普顿大学光电子研究中心以及6个世界领先的工业合作伙伴（包括网络和服务提供商（BT和KDDI），设备系统（Xtera和诺基亚）和光纤/放大器（康宁/OFS）制造商）之间的合作提出的，证明了这项研究的战略重要性。无处不在、宽带、高容量、低延迟和安全的电信基础设施对英国的未来和经济成功至关重要。国家电信设备多样化工作组（https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/975007/April_2021_Telecoms_Diversification_Taskforce_Findings_and_Report_v2.pdf）最近发布的报告强调了研发的必要性，以确保这一点：“研究、开发和创新是开发新的电信解决方案和技术的核心，也是现有供应商的主要竞争优势。因此，研发活动和投资对于推动多元化至关重要，“建议”政府应该投资于旨在英国早期开发和系统集成技能增长的项目。这些项目将确保英国在这一领域建立竞争优势，并作为其建立英国能力雄心的早期要素。”EWOC提案侧重于这两个目标。

The exponential growth in the use of bandwidth-hungry internet services such as high-definition video streaming, cloud computing, artificial intelligence, Big Data and the Internet of Things requires new advances in optical data transmission technologies to achieve ultra-high throughputs and minimal latencies. To go beyond current channel limits is arguably the greatest challenge faced by digital optical communications. To target it, the proposed research programme will develop new approaches to significantly increase the capacity of future communication systems focusing on the ultrawideband optical transmission and amplification in combination with adaptative coded modulation and digital signal processing, to ensure a robust communications infrastructure beyond tomorrow. Systems capacity is bounded by three dimensions: bandwidth, information spectral density and space. Whilst much research has focused on maximising the information spectral density and investigating space division multiplexing, little attention has been paid to the bandwidth domain. We propose to significantly extend the channel bandwidth with transceivers, broadband optical amplifiers, beyond the well-established erbium doped fibre amplifier (EDFA), focusing on bismuth and thulium doped fibre amplifiers with the assistance of Raman-amplification. Together with space division multiplexing, based on multiple fibres or new multi-core fibres, will ensure system capacities of tens of Petabit/s will be possible in the future. In EWOC research, we will gain a deeper understanding of the fundamental nonlinear effects that govern the upper limit on capacity in such ultra-wide systems, never previously investigated. Three main challenges are: (i) to fully utilise the bandwidth of the ubiquitous silica fibres low-loss window, overcoming the single mode fibre constraints, to reach bit rates of up to 250 Tb/s per core; (ii) to operate beyond the Raman gain shift - means that the associated nonlinear signal-to-signal interference in the widely diverse dispersion and nonlinearity regimes must be understood, quantified and effectively mitigated and (iii) experimentally demonstrate the combination of the significantly increased bandwidth with novel coded modulation, advanced DSP and nonlinearity mitigation in a wide variety of distance and bitrate transmission scenarios and applications in core, access and data centre networks. The EWOC proposal is a collaboration between UCL's Optical Networks Group and the University of Southampton Optoelectronics Research Centre and 6 world-leading industrial partners spanning network and service providers (BT and KDDI), equipment systems (Xtera and Nokia) and optical fibre/amplifier (Corning/OFS) manufacturers, a testament to the strategic importance of this research. The importance of ubiquitous, broadband, high-capacity, low delay and secure telecommunications infrastructure is critical to the UK's future and economic success. The recently published report of the National Taskforce on Telecoms Equipment Diversification Task Force (https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/975007/April_2021_Telecoms_Diversification_Taskforce_Findings_and_Report_v2.pdf) has highlighted the need for R&D to ensure this: 'Research, development and innovation are central to the development of new telecoms solutions and technologies and a major competitive advantage for incumbent vendors. Therefore, R&D activity and investment is vital in driving diversification' recommending 'The Government should invest in projects aimed at early development and growth of systems integration skills in the UK. Such projects will ensure it builds a competitive advantage in this domain, and as an early element of its ambition to build UK capability'. The EWOC proposal is focused on both of these goals.