Fibre Wavelength Quantum Light Sources

The Sheffield team and the National Centre for III-V technologies will develop quantum dot single photon emitters for
Quantum Communications. The overall project aims are to demonstrate the controlled emission of entangled photons from
an LED structure emitting at a fibre-compatible wavelengths. Devices operating at this wavelength will be required to
achieve commercially significant Quantum Communications technologies. There is a significant epitaxy challenge in
developing this technology by Metal Organic Vapour Phase Epitaxy (MOVPE) at these wavelengths and there have been
no demonstrations of entangled LEDs to date.
The Sheffield team will develop Indium Arsenide on Indium Phosphide quantum dots by MOVPE , complementing and
contrasting with the development by the Molecular Beam Epitaxy (MBE) method in the Cavendish laboratory. To
demonstrate single photon emitters at these wavelengths is challenging and there is a need to investigate the properties of
the quantum dots by both techniques to understand how the quantum dots form and what controls the fundamental
properties that will generate photon entanglement; including aspects such as the exciton spin splitting value. The work will
build significantly on the prior work carried out at shorter wavelengths in Sheffield, Toshiba and Cavendish laboratories
using a different material system. In particular at Sheffield the result of quantum dot structures developed under an EPSRC
Programme Grant will benefit the project strongly since many of the physical properties may be similar. The demonstration
of high quality devices at this wavelength will be a significant milestone in matching Quantum Communications to the
current non-quantum fibre-communications infrastructure.

Exploitable outcomes will include IPR and technology related to single photon generation, growth of quantum dots and
fabrication of quantum devices. There is also the potential for IPR on the application of the device to areas such as
quantum key distribution, quantum relays/repeaters, quantum sensors, quantum imaging and photonic quantum computing.
We will seek to exploit the outcomes of the project through a close interaction with the EPSRC Quantum Technology Hubs,
especially those which have a strong focus upon photonic technologies and to which we can make a strong collaborative
contribution. It should be noted that none of the EPSRC Hubs are funded to develop quantum light sources. In
collaboration with the Quantum Communication Hub (co-ordinated by York) we will develop systems for quantum
relays/repeaters and quantum digital signatures based upon fibre wavelength entangled LEDs developed in this project.
Dissemination will be achieved through patent publications, scientific papers (eg recent reports by the applicants on
quantum light generation have been published in Nature, Nature Photonics, Nature Communications and Applied Physics
Letters) and presentations at relevant international conferences (such as Photonics West, ECOC, OFC, CLEO, CLEO
Europe, QCrypt, QCMC).
The know-how developed in the project will be added to the capabilities of the National Centre for III-V Technologies and
will be available as a resource for the broader UK academic community through EPSRC, TSB or EU research grants. This
significantly increases the leverage of the project through dissemination into a broader set of R&D projects and other
applications areas such as telecommunication lasers and detectors.
TREL chair the Industry Standardisation Group (ISG) on Quantum Key Distribution (QKD) of the European
Telecommunication Standards Institute. We expect the outcomes of this project to contribute to the active work item of the
ISG on Components used for QKD. This is defining how quantum components should be tested and specified for QT
system integrators, which is an important dissemination activity for stimulating QT component supply chains.
We will disseminate to industry and potential customers via press releases and feature articles in the specialist press (such
as Photonics Spectra), taking part in InnovateUK dissemination events and joint publicity with the EPSRC QT Hubs. An
Exploitation Advisory Group will advise the project on exploitation of project results. The initial membership of the EAG
includes representatives from the EPSRC QT Hubs and senior industrialists and researchers with experience of technology
and business innovation.
We will explore exploitation in schemes for eye-safe quantum enhanced LIDAR in the Quantum Imaging Hub (Glasgow).