February 23, 2026 -- Could quantum physics make tomorrow's telecommunications networks unhackable? That is the challenge taken up by the QUALITY project, a large-scale initiative led by Professor Roberto Morandotti of INRS-EMT, with the active participation of ÉTS faculty members Christine Tremblay and Kim Khoa Nguyen, and researchers from McGill University and the University of Toronto. The goal of this project is to develop a new generation of quantum technologies that can be directly integrated into existing telecom infrastructures.

Quantum technologies integrated into classical networks

Telecommunications networks rely on optical fibers in which light signals, called channels, propagate at different frequencies. These conventional systems can typically carry up to 80 channels, each transmitting at 100 Gb/s. The concept behind the QUALITY project is to introduce one or more additional quantum channels into the same fiber. Unlike classical channels, these are not intended to carry user data, but rather to distribute cryptographic keys that can be used to secure communications.

This concept, known as quantum key distribution (QKD), is emerging as a response to the very real threat posed by the advent of quantum computers. Their computational power could ultimately render many of today’s widely used encryption methods obsolete. A hacker could intercept and store encrypted data now, only to decrypt it later once sufficiently powerful quantum technologies become available. By integrating quantum cryptography into fibre optic networks, the objective is to ensure long-term confidentiality of sensitive communications.

The challenge of coexistence

Building a parallel network entirely dedicated to quantum signals might appear to be a straightforward solution, but it would be prohibitively expensive. The cost of civil engineering works, fiber deployment, and specialized telecom equipment makes this approach unrealistic. Instead, quantum and classical signals must coexist in the same optical fibers, a solution that introduces significant technical challenges.

In a hybrid network, only a handful of quantum photons propagate through the fiber alongside the millions of photons that carry conventional signals. These rare photons, which encode the cryptographic keys, are extremely fragile: they can easily be overwhelmed by optical noise or disturbed by interference from neighbouring channels.

This is where the expertise of ÉTS comes into play. The team led by Christine Tremblay, a specialist in optical communications, and Kim Khoa Nguyen, an expert in software-defined networking (SDN), is developing a hybrid classical-quantum network testbed to investigate different coexistence scenarios. Using this platform, experiments on the simultaneous transmission of quantum and classical signals are conducted by adjusting key parameters such as channel allocation, frequency selection, node architecture, and network resource sharing.

A unique infrastructure in Canada

ÉTS has an internal fibre optic network spanning over 2,500 km, with the ability to connect to external networks as needed. This infrastructure provides a real-world experimental platform for studying the coexistence of quantum and classical signals. Researchers will be able to evaluate the quality of recovered quantum photons, the key exchange rates, and the throughput of classical channels.

Initial tests are promising: a 800 Gb/s connection incorporating a point-to-point quantum channel has already been demonstrated, confirming the feasibility of the concept.

The researchers will initially use commercially available equipment to perform baseline experiments and establish reference performance benchmarks. Subsequently, the quantum technologies developed by the QUALITY project team will be integrated into this experimental testbed to evaluate their performance against existing solutions.

A collaborative ecosystem

The QUALITY project is part of a broader ecosystem focused on collaboration and expertise- sharing. Notable examples include the ÉTS Institute of Quantum Science and Engineering, which brings together researchers exploring practical applications of quantum technologies, and Numana, the organization behind the KIRQ testbed. This testbed provides organizations with an environment to test and validate their innovations in quantum telecommunications and cybersecurity.

Training tomorrow’s network engineers

This project also offers students an exceptional learning environment, enabling them to develop dual expertise in conventional optical networking and quantum communications. Once mature, the solutions developed within the QUALITY project will provide telecom operators with practical guidelines for adapting their infrastructures to future security requirements.

Artificial intelligence to the rescue

Finally, the ÉTS team is also exploring the use of artificial intelligence (AI) to optimize resource allocation in these complex hybrid networks. Given the multitude of variables to be adjusted—data rates, channel frequencies, photon quality, and link stability—AI could play a pivotal role in making the coexistence of quantum and classical signals not only feasible, but also efficient.