Advancing Quantum Communications using Next-Generation Optical Fibre

安全通信技术是当今数字经济的支柱，但目前用于保护通过光纤网络传输的全球通信的加密工具的安全性是基于“计算复杂性”的。这假设窃听者的计算资源有限，无法破解复杂的数学问题。这种假设在即将到来的量子计算时代已经失效，因此迫切需要采取行动来确保通信系统的持续安全。量子密钥分发(QKD)是一种迅速成熟的技术，它通过使用量子光来分发秘密数字密钥来解决这一问题。作为一项前沿技术，量子密钥分发系统的发展本质上是多学科的。这需要量子物理、高速电子学、低损耗光子学和高性能软件的仔细融合来产生、操纵和测量光。虽然量子密钥分配已经成功地部署到世界各地的许多光网络中，但它一直使用“标准”的单模电信光纤。最近，下一代光纤的发展有了很大的进步，使用新的物理设计来实现非常不同的光学制导特性。这种几何结构包括空芯和少模光纤，这为光通信提供了许多优势。例如，这使得空分多路复用能够增强光纤的传统数据传送能力，并减少非线性和色散效应，以及减少等待时间。这种新光纤也可以为量子通信提供许多好处，但这些好处还有待开发。东芝欧洲有限公司的一个博士项目可以对利用下一代光纤的量子通信系统的开发进行开创性研究。该项目将从新型光纤的详细光学特征开始，测量各种线性和非线性光学现象，重点是这些现象如何影响经典光信号和量子光信号之间的相互作用。然后，候选人将在全量子密钥分发系统的实验开发中发挥领导作用，设计、建造和表征将通过新型光纤连接的光发射器和接收器模块。这将包括广泛的实验研究，结合高速光学和电子设备，以及开发控制软件。预计应聘者将在半导体激光、短脉冲产生、光学调制、高速射频电子学、线性和非线性光纤光学、量子光子学和单光子光检测方面拥有广泛的专业知识。也有机会进行理论工作，以模拟和优化光学系统和基本的量子通信协议。

Secure communication technologies are the backbone of today's digital economy yet the security of current cryptographic tools, which are applied to protect global communications travelling across a network of optical fibre, is based on 'computational complexity'. This assumes an eavesdropper has limited computational resources to break complex mathematical problems. This assumption is invalidated in the coming quantum computing era and thus, urgent action is needed to ensure the continued security of our communication systems.Quantum key distribution (QKD) is a rapidly maturing technology that solves this problem by distributing secret digital keys using quantum light. As a frontier technology, the development of QKD systems is inherently multidisciplinary. This requires the careful fusion of quantum physics, high-speed electronics, low-loss photonics and high-performance software to generate, manipulate and measure light.While QKD has already been successfully deployed to many optical networks worldwide, this has always employed "standard" single-mode telecommunication fibre. Recently, there has been great progress in the development of nextgeneration optical fibres, using novel physical designs to achieve very different optical guidance characteristics. Such geometries include hollow-core and fewmode fibres, which offer many advantages for optical communications. This enables, for example, spatial division multiplexing to enhance the classical datacarrying capacity of fibre and reduction of nonlinear and dispersive effects, as well as reduced latency. Such new fibres could also offer many benefits for quantum communications, but these have yet to be explored.A PhD project based at Toshiba Europe Ltd is available to perform pioneering research into the development of quantum communication systems that exploit next-generation optical fibres. The project will commence with detailed optical characterisation of new types of optical fibres, measuring various linear and onlinear optical phenomena with a focus on how these affect the interaction between classical and quantum light signals. The candidate will then play a leading role in the experimental development of full QKD systems, designing, building and characterising optical transmitter and receiver modules to be connected by new types of optical fibre. This will involve extensive experimental research, combining both high-speed optical and electronic devices, in addition to developing control software. It is expected that the candidate will develop broad expertise with semiconductor lasers, short-pulse generation, optical modulation, high-speed RF electronics, linear and nonlinear fibre optics, quantum photonics, and single-photon photodetection. There are also opportunities for theoretical work to simulate and optimise optical systems and the underlying quantum communication protocols.