Co-integration of microelectronics and integrated photonics for quantum technologies

预计在未来20年内，实用量子计算机的出现将对大多数标准加密系统构成严重威胁。量子密钥分发（QKD）和量子随机数生成器（qrng）旨在利用量子力学定律提高通信和个人数据的安全性，并为恶意使用量子计算机造成的威胁提供解决方案。qrng利用了量子测量的概率性质，产生了真正的随机数。这与目前结合使用混沌系统和基于软件的伪随机数生成器生成随机数的方法相反。QKD系统利用量子系统的特定特征，如量子态的叠加和“不可克隆”定理，使各方能够以本质上安全的方式交换加密密钥。由于QKD密钥交换基于物理系统，而不是基于软件的加密方法，因此QKD也是“面向未来的”，因为黑客算法的任何改进都不会影响协议的安全性。在过去的几年里，QKD和QRNG社区的努力首先集中在生产实验室原型上，最近则集中在提供商业系统上，这些系统已经在全球范围内小规模地部署。然而，对于诸如外形尺寸、技术可扩展性以及功耗和成本等关键方面的关注却很少。用光纤和分立电子元件构建的系统不可避免地昂贵、笨重、性能有限，因此本质上是不可扩展的。KETS量子安全有限公司是量子工程技术实验室（布里斯托尔大学）的分支机构，通过结合集成光子学技术和量子加密协议的优势来解决可扩展性问题。虽然集成光子芯片大大减小了核心光学系统的尺寸，但离散电子元件和光子芯片之间的分离本质上限制了量子技术的整体性能。此外，这增加了设备的尺寸和成本，限制了这种QKD和QRNG系统的推广。该奖学金的重点将是开发一些新的关键集成光电子系统，其中微电子和量子光子学将在同一半导体衬底上单片集成。电子学和光子学的单片集成是向前迈出的关键技术一步，它将为一系列全新的解决方案开辟道路，并将潜在地提高量子技术的性能。这可能会给QKD和QRNG系统带来突破性的改进，为它们与现代数字技术的直接集成开辟道路。

The advent of practical quantum computers, expected within the next two decades, poses a serious threat to most of standard encryption systems. Quantum Key Distribution (QKD) and Quantum Random Number Generators (QRNGs) aim to enhance security of communications and personal data by exploiting the laws of Quantum Mechanics and provide the solution to threat caused by a malicious use of quantum computers. QRNGs, exploiting the probabilistic nature of quantum measurements, produce truly random numbers. This is in opposition with current methods to generate random numbers which combine the use of chaotic systems and software-based pseudo random number generators. QKD systems taking advantage specific features of quantum systems such as superposition of quantum states and the "no-cloning" theorem enable parties to exchange cryptographic keys in an intrinsically secure way. Because QKD key exchange is based on physical systems as opposed to software-based encryption methods, QKD is also "future-proof" as no improvement on hacking algorithm will affect the security of the protocols.In the last few years, the efforts of the QKD and QRNG community have focused first to produce lab prototypes and more recently to provide commercial systems, which have been deployed in small scale around the globe. However, less focus has been placed on key aspects such as the form factor and technology scalability as well as power consumption and costs. Systems built with optical fibres and discrete electronics components are inevitably expensive, bulky, and limited in terms of performance and therefore intrinsically not scalable. KETS Quantum Security Ltd, spin-off of the Quantum Engineering Technology Labs (University of Bristol) has been addressing the scalability issues by combining the advantages of integrated photonics technologies and quantum cryptography protocols. While the integrated photonic chips have significantly reduced the size of the core optical system, separation between discrete electronic components and photonic chips inherently limits the overall performance of the quantum technology. Moreover, this increases the size of the devices and their costs, limiting the spread of this QKD and QRNG systems. The focus of this fellowship would be the development of some novel critical integrated opto-electronics systems, where microelectronics and quantum photonics will be monolithically integrated on the same semiconductor substrate. Monolithic integration of electronics and photonics is a critical technological step forward that will open the way to a whole new range of solutions and will improve the performance of quantum technologies potentially by orders of magnitude. This could bring groundbreaking improvements to QKD and QRNG systems, opening the way to their direct integration onto modern digital technologies.