Kimia Mohammadi (MSc '22, PhD in progress)
Student, Faculty of Science
> Institute for Quantum Computing
In our increasingly digital and interconnected world, graduate students like Kimia Mohammadi constantly innovate to stay ahead of emerging security risks. She is part of a national team creating Canada's first quantum satellite, currently scheduled for launch in 2025. The Quantum EncrYption and Science Satellite (QEYSSat) mission will be a demonstration of secure ground-to-space quantum communication.
"QEYSSat is a huge milestone for Canadian technology," says Mohammadi, a PhD student in the University of Waterloo's Department of Physics and Astronomy, and the Institute for Quantum Computing (IQC). "It's so satisfying to see my research play a role in the future of communication."
Leading QEYSSat's national science team is Mohammadi's graduate supervisor, Dr. Thomas Jennewein, a professor in Waterloo's Department of Physics and Astronomy and a faculty member at IQC. Jennewein's research aims to create a global quantum internet, developing the technologies to realize secure satellite-based quantum communications. His research also sheds light on fundamental questions in quantum physics as he explores quantum entanglement over large distances and speeds.
The key to quantum encryption
Jennewein, Mohammadi and the QEYSSat team use a technique called "quantum key distribution" to generate encrypted keys sent between the satellite and researchers on Earth. These cryptographic keys take advantage of a quantum mechanics property, asserting that a quantum state cannot be observed without changing it. Therefore, if the secret quantum key is observed or copied, a detectible trace is left, so the researchers know that the key has been compromised and is no longer secure.
"Quantum signals are secure because they cannot be copied. However, this also makes it difficult to transmit through fibreoptic cables over large distances, unlike classical signals which rely on signal repetition and amplification," Jennewein says. "So, to successfully transmit a QKD signal over large distances, we need methods such as satellites that don't rely on signal repetition."
With the science headquartered at IQC, Canada's anchor-point of the quantum ecosystem, QEYSSat will communicate with research ground stations at both the University of Waterloo and the Canadian Space Agency headquarters in Saint-Hubert, Quebec. These ground stations will generate quantum signals using photons of light and send them up to the satellite. Such quantum satellites could then be used as a trusted relay to send these signals between the ground stations.
One distinct advantage of this configuration is that since the photons are being sent from Earth to the satellite, the research teams will have the advantage of flexibility, being able to change the source of the photons or update the device as new technologies are developed.
Mohammadi is currently working to ensure that the Waterloo ground station can find and communicate with the satellite using their telescope transceiver, which she built during her previous master's degree, located on the roof of the Research Advancement Complex at the north end of Waterloo's Research and Technology Park.
"Most people wouldn't like to go to the telescope at 2 a.m. to do optical alignments via stars or track objects such as the International Space Station, but for me, it's fascinating to take each small step toward having a fully functional ground station once the satellite is launched," she says. "Thomas gave me the opportunity to design and build our own telescope, which will be used in our future free-space communication experiments."
Canadian satellites for quantum security
Launching a satellite like QEYSSat is an interdisciplinary undertaking. Experts in physics develop the scientific basis for the quantum communication efforts; engineering experts build the satellite components and ensure they will survive the launch and harsh conditions of outer space; and industry partners, including the Canadian Space Agency and Honeywell, are guiding the satellite launch and manufacturing.
Looking forward, Mohammadi and Jennewein have also explored realistic future satellite scenarios and identified current technological bottlenecks in the project QEYSSat 2.0 to demonstrate the technologies necessary for developing a quantum internet across Canada.
While the QEYSSat mission will be a demonstration of quantum key distribution and secure communication to a satellite, it is paving the way for Canada to be a leader in secure communication in the quantum age. As an entirely Canadian-owned project, it is focused on creating a future prioritizing national security and sovereignty.
"Governments around the world, including Canada, have recently announced national quantum strategies," Jennewein says. "Once quantum computers come online, our current encryption methods become potentially vulnerable, and world leaders are recognizing the importance of becoming quantum literate and quantum ready."
