Co-integration of microelectronics and integrated photonics for quantum technologies

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.