Taking quantum into space

Privacy and data security are two of the hottest topics in the news today.

One opportunity for ultra-secure communication is quantum key distribution (QKD). QKD utilizes the laws of quantum mechanics to establish a secure key between two parties — a key comprised of entangled photons, particles of light. Once this key is established, any attempt to intercept the key will be detected — quantum mechanics tell us that if you look at a quantum state you perturb it, so the state of the key will be disturbed. Unlike systems today where we don’t know that systems are being intercepted, QKD establishes a truly secure network where you can continue to exchange keys until a secure channel is created.

Today’s commercial QKD systems connect through fibre-optic cable, but are limited to less than 200 kilometres before the photons are absorbed into the fibre. With quantum repeaters still in the very early phases of research, the challenge becomes establishing a quantum network at global distances.

This is a challenge IQC faculty member Thomas Jennewein, a professor of physics in the Faculty of Science, and his team including postdoctoral fellow Brendon Higgins and PhD students Jean-Philippe Bourgoin, Catherine Holloway and Chris Pugh have gladly accepted. Their research looks to create a global quantum communications network using satellites.

Jennewein’s satellite mission proposal, Quantum Encryption and Science Satellite project (QEYSSAT), brings together the Canadian Space Agency and space hardware designer and manufacturer COM DEV for the development of a global satellite-based quantum communications network. In this satellite project, quantum information is generated and distributed using single or entangled photon sources located at a ground station and sent in a tight beam up towards the satellite receiver — called an “uplink.”

By keeping the photon source on the ground and sending the photons up, Jennewein and his team can manipulate the ground source — a more complex and fragile technology than the photon detectors on the satellite — which allows flexibility for future experiments, expanding the potential possibilities of the project.

With support from the Canadian Space Agency, Government of Canada’s Federal Economic Development Agency for Southern Ontario and collaborators from Communitech’s DATA.Base project, IQC is advancing the overall concept of the satellite mission proposal and showing the readiness of this quantum technology for space.

The next step in the project will be to demonstrate the satellite pointing system to track and maintain a link between a fixed ground station and a moving quantum receiver. The low-earth orbit satellite when in operation will be located about 500-600 kilometres from the ground and will move at speeds in excess of 25,000 kilometres per hour.

In preliminary experiments, the quantum transmitter stationed on the Research Advancement Centre (RAC) on the north end of the University of Waterloo campus and the current home of Jennewein’s lab, performs QKD with a receiver mounted to a moving vehicle. Eventually, the team will mount the receiver to a flying system, such as a hot air balloon or a plane, to further advance the evolution of quantum transmission between a ground station and a moving satellite in space.

Once the satellite pointing system is successfully proven, Jennewein looks forward to collaborating with research groups around the world to demonstrate several quantum transmissions, moving one step closer to establishing a global quantum communications network.

A collaborative approach

Collaboration with other IQC researchers contributes to the progress of the satellite project. Jennewein works with experimentalist Vadim Makarovand theorists Norbert Lutkenhaus and Michele Mosca, experts in quantum cryptography and security theory, to bring the fundamental theory of quantum communications to realization through the development of working quantum devices and real-world applications.

Envisioning the future of quantum communications

Jennewein is confident that the cutting-edge research happening in the field of quantum communications will change the way we send, receive and store our private data as quantum computers become more practical. What possibilities could a secure quantum communications network lead to? Jennewein predicts a global exchange of quantum information between many different users may be next, laying the possible framework for the realization of a global-scale exchange of quantum information — the quantum internet.