Quantum Dots for Entanglement-based Quantum Key Distribution

Entanglement is a fundamental ingredient for extending quantum key distribution from two-party communication to networks without trusted nodes. Yet, the commercial application of this concept is currently hindered by the probabilistic nature of the photon-generation process underlying the used entanglement resources.
QD-E-QKD will develop a novel technology based on semiconductor quantum dots and test it in realistic urban communication scenarios to surpass the limits of current approaches to entanglement-based quantum key distribution.
Our photonic source will combine recent research developments in microfabrication in a single device. Its structural design will embed high-quality epitaxial quantum dots and include a p-i-n-i-n diode for the suppression of charge noise, a circular Bragg grating cavity for brightness enhancement, and a piezoelectric substrate for optimal entanglement. We predict that our device will operate—at near-unity degree of entanglement—at rates that are more than one order of magnitude higher that those accessible by state-ofthe-art parametric down converters for the same qubit error rate. At the same time, the near-zero multi-pair emission probability guarantees better robustness against channel attenuation losses in the communication protocol implementation.
We will use this device to implement quantum key distribution using two quantum-channel approaches, a single-mode fiber and free space. To guarantee stable operation we will develop a stand-alone device that combines time-to-digital conversion with optical clock recovery for remote synchronization and a free spaceoptical-communication receiver with integrated adaptive optics based on deformable lenses.
Finally, we will provide quantitative benchmarking, backed by theoretical modelling and testing, to certify the advancement over existing entanglement-based quantum key distribution systems. This will offer a viable technology for the realization of more complex quantum key distribution networks.




  • Coordinator: Rinaldo Trotta (Sapienza University of Rome, Physics Department, IT)
  • Stefano Bonora (CNR / IFN Padova, IT)
  • Tobias Huber (Julius Maximilians Universität Würzburg / Technische Physik, DE)
  • Henning Weier (Quantum Technology Laboratories Deutschland GmbH, DE)
  • Armando Rastelli (Johannes Kepler University / Institute of Semiconductor & Solid State Physics, AT)
  • Thomas Scheidl (Quantum Technology Laboratories GmbH, AT)
  • Vladyslav Usenko (Palacký University, Olomouc, Faculty of Science, CZ)


Call year

Call 2021

Call topic

Applied Quantum Science

Area of research

Quantum communication

Start date

May 2022


36 months

Funding support

€ 1 761 370

Project status

In Progress