Lithium niobate integrated quantum photonics

Quantum information science has the potential to revolutionise information and communications technologies (ICT) in the 21st century via secure communication, precision measurement, and ultra-powerful simulation and ultimately computation. Photonics is destined for a central role - the photon is an ideal quantum bit, or 'qubit', for encoding, processing, and transmitting quantum information. However, real-world applications require integrated photonic devices, incorporating photon sources, detectors and circuits. Just as the invention of the silicon integrated circuit turned the tremendous potential of the transistor into reality, this project aims to develop all necessary components to the high levels of performance and integration required to realise quantum photonic technologies. This project will be the first to simultaneously address all components and their integration simultaneously. It will thereby overcome the major challenges to realising the tremendous potential of future quantum technologies.

A key challenge in the development and application of our approach is to integrate waveguide circuits with active components: single-photon sources, phase- and amplitude-modulators and high-efficiency single-photon detectors. Our initial benchmarking and characterisation results have identified lithium niobate (LN) as the perfect material system in which to realise all of these components and thereby to create a new paradigm for integrated quantum photonics. The goals of this proposal are to fabricate all of the key devices in the LN material system and to integrate them to realise the first prototype systems. Telecom wavelength operation will enable interfacing with existing telecom systems (existing fibre optic networks for example) and the adoption of powerful telecom technologies (modulators, wavelength division multiplexing, arrayed waveguide gratings, etc.).

The devices and systems developed in this programme will revolutionise approaches to photonic quantum technologies, paving the way to practical applications. This project brings together all of the essential expertise required to achieve these ambitious goals in world-leading groups in quantum photonic technologies and LN device fabrication (Bristol), superconducting single-photon detectors (Heriot-Watt), and superconducting thin film growth and nanofabrication (Cambridge). This proposal builds on successful work within and between these groups and has substantial support from our exisiting industrial partners (The UK National Physical Laboratory, Nokia and Quantum Technology Research Ltd.). Over the last several years the applicants have already made great strides towards integrated quantum photonic technologies, developing waveguide-on-chip quantum photonic circuits, combined with practical superconducting single photon detectors, and non-linear photon sources.

This research proposal is extremely timely in addressing a critical bottleneck in the development of optical quantum information technologies: a single material system that can support all of the required components and their integration. Our research programme will provide a launching pad to a new generation of compact, high performance quantum photonic devices operating at telecom wavelengths. We adopt a highly novel and ambitious approach in migrating from silica-on-silicon waveguide circuits to LN waveguide circuits. This will enable us to integrate periodically poled lithium niobate (PPLN) photon sources, rapidly reconfigurable waveguide circuits and high performance superconducting single-photon detectors together for the first time, and to achieve high performance operation at telecom wavelengths. This approach promises a new technology platform for realising secure communication networks, precision measurement systems, simulation of important physical, chemical and biological systems, including new materials and pharmaceuticals, and ultimately ultra-powerful computers.

This ambitious EPSRC Project is aimed at developing and bringing together novel optical quantum information processing components into single chip devices. These integrated devices will represent a step change in the state-of-the-art for communication and computing technology. This Project is designed to have far-reaching impacts beyond the academic research community, both during the 4-year Project span and in the longer term.

Impact 1: Benefits to High Tech Industry in the UK

This Project is of strong relevance and interest to high tech industry, with significant potential future benefits for the UK economy. The main applications are foreseen in the areas of high performance (quantum) communications and computing, with likely further uses in a wide range of fields, from medical research to defence. We have enlisted the support of three major Project Partners who will provide support for the Project and guidance towards end-applications. The National Physical Laboratory (NPL) is the UKs national metrology laboratory, providing advanced technology to support the current and future needs of UK industry. Our technology will support and accelerate NPL efforts in next-generation optical metrology and communication standards. Nokia is a major global player in the advanced communications technology arena. Nokia has shown a significant commitment to UK economic growth by setting up substantial research and development centre in Cambridge, UK. Finally Quantum Technology Research Ltd is a forward-looking UK start-up, focussed on securing investment to underpin the exploitation of emerging quantum technologies. We aim to further strengthen links with these Partners via exchange of personnel and joint Project meetings. By forging these robust connections at the outset, we aim to ensure the rapid uptake of our technology in real-world applications. We estimate that the first Project outputs will reach commercial applications within 10 years of the beginning of the Project.

Impact 2: Training of Researchers for the UK Knowledge Economy

The second major impact of this Project will be in the training of young researchers. This Project will train a team of talented postgraduate and postdoctoral researchers in a fast moving area at the frontier of science and technology. Our Project will provide opportunities for undergraduate and masters level students to carry out cutting edge research in the laboratory for the first time often a decisive factor in whether these individuals choose to continue a career in scientific research or high tech industry. These researchers are likely to be highly valued in their future careers in science or industry, with corresponding benefit to the UK knowledge economy over the coming decades.

Impact 3: Inspiration for a New Generation of UK Scientists and Engineers

Finally the results and outputs of this Project will be publicised in both the scientific and general news media. We believe our work represents an outstanding example of world-leading research carried out in the UK, and we will make every effort to highlight our successes to as wide an audience as possible. This will provide inspiration for a new generation of young people to take up careers in science and engineering. We consider this a valuable long term impact of our Project.