Scientists from the School of Engineering and Physical Sciences, Heriot-Watt University, have created a prototype quantum network. This network connects two smaller networks into a single, adaptable system. It can accommodate eight users and can route and teleport entanglement as needed. The study represents a significant advancement in the size, flexibility, and capabilities of quantum networks. The study was published in Nature Photonics.
Image Credit: Heriot-Watt University
Scientists have long envisioned a quantum internet, a global network for secure communication and advanced computation using the connections between light particles.
Other teams had already demonstrated that you can build a single quantum network and send entanglement to many users at once. But this is the first time anyone has managed to link two separate networks together. It doesn’t just distribute entanglement in different ways, it actually lets one network talk to the other. This is a major milestone on the road to a real-world quantum internet.
Mehul Malik, Professor, School of Engineering and Physical Sciences, Heriot-Watt University
Using Light’s Chaos as a Resource
The Heriot-Watt prototype utilizes an off-the-shelf optical fiber, costing under £100, as its core component.
The team utilized the light scattering properties within the optical fiber to program their reconfigurable entanglement router.
Dr Natalia Herrera Valencia, lead author of the study, notes, “Light tends to ricochet chaotically through the fibers’ hundreds of internal pathways. We turned that chaos into a resource.”
The outcome is a reconfigurable multi-port device capable of distributing quantum entanglement among users in various configurations. It can switch between local connections, global connections, and mixed configurations as needed.
The system can multiplex these channels, enabling simultaneous service to multiple users, unlike previous systems that served one pair at a time. This multiplexing concept, similar to classical telecoms, allows for the transmission of multiple quantum channels within a single fiber.
The team demonstrated multiplexed entanglement teleportation, swapping entanglement between four distant users across two channels concurrently. This surpasses previous demonstrations in terms of the number of simultaneous users and the flexibility of the architecture.
By shaping the light at the input, we effectively programmed the fiber, transforming its messy internal scattering into a powerful, high-dimensional optical circuit. That lets us route quantum entanglement wherever we want, even teleport it, using this deceptively simple piece of fiber.
Dr. Natalia Herrera Valencia, Heriot-Watt University
A Leap for Quantum Computing
Professor Malik highlights the demonstration's promising potential for quantum computing.
It’s really exciting. Quantum computing could be world-changing, transforming how we find and develop medicines, create new materials for batteries, and supercharge machine learning. A promising current approach to building a large-scale, powerful quantum computer is to interconnect lots of smaller quantum processors.
Mehul Malik, Professor, School of Engineering and Physical Sciences, Heriot-Watt University
“Our prototype is a network that can flexibly distribute and swap entanglement among many users, or quantum processors - it could be the breakthrough quantum computing has been waiting for. Yes, this is a lab-scale demonstration, but the principle is extendable,” continued Malik.
The study is associated with the £22 m Integrated Quantum Networks (IQN) Hub, a project aiming to establish the UK's first large-scale quantum network. The project, led by Heriot-Watt University, is funded by the Engineering and Physical Sciences Research Council (EPSRC). It involves 14 UK universities and over 50 industrial partners, with the goal of securing the UK's leadership in quantum networking.
The Hub's objectives are in line with the UK Government's national quantum strategic missions, specifically the deployment of the world's most advanced quantum network by 2035. This study was funded by the UK Engineering and Physical Sciences Research Council (EPSRC), the European Research Council (ERC), and the Royal Academy of Engineering. The study was conducted by Heriot-Watt University’s Beyond Binary Quantum Information Lab in collaboration with the Edinburgh Mostly Quantum Lab.
Journal Reference:
Malik, M., et al. (2025) A large-scale reconfigurable multiplexed quantum photonic network. Nature Photonics. DOI:10.1038/s41566-025-01806-x. https://www.nature.com/articles/s41566-025-01806-x