Quantum Waveguides for Indistinguishable Single Photon Sources (QWISPS)

Covesion Ltd and The University of Southampton plan a collaborative feasibility study to investigate the use of periodicallypoled
lithium niobate crystals in single-photon sources for applications exploiting quantum entanglement. Our crystals
enable the energy of a single photon to be split and conserved as two lower-energy photons at different colours; the laws of
physics state that if one of these photons is created then the other must also exist. In this project, we seek to reduce the
manufacturing tolerances required to generate indistinguisable photons between parallel sources and our objective is to
prove our new approach across multiple devices. This is an important step in enabling scalable quantum applications
where many indistinguishable photons are needed in parallel, such as quantum computing.

Economic benefits arising from this project are an expected increase in Covesion turnover based on crystal sales, plus
potential for further VC investment and growth via the development of higher-value single photon sources. These benefits
will spill-over to Covesion's supply chain, which includes specialist raw material providers, equipment suppliers, and coating
services across the UK and Europe. Periodically-poled materials are expected to be an enabling component for quantum
communications, which is expected to grow to a $Bn market in 2018 with over 50% of the required expertise based in
Europe.
Socially, additional turnover equates to new jobs at Covesion, including engineers, technical, sales and admin staff.
Investment in quantum technologies will enable the UK to maintain an important technology lead and train a new
generation of engineers and physicists with sought-after high-level skills. Engagement with industry will enable those
engineers to find jobs relevant to their training, while engagement with UK policy makers Innovate UK, DSTL and EPSRC
will ensure government priorities remain focussed on funding initiatives in areas of UK-centric expertise.
Environmentally, this feasibility study is a first step towards our ultimate aim of replacing bench-level experiments and
components with integrated systems the size of a (large) matchbox. While we only process a few kilograms of raw crystal
per year, the proportional size of a PPLN waveguide device versus bulk is around 10%, allowing us to reduce material
waste and process steps (photolithography, dicing, polishing, etc) by 90%, reducing our chemical waste by tens of litres per
year. This will become more significant as volumes increase.