Eurofiber and Delft Networks have established a closed-loop, entanglement-ready dark fiber network directly linking Delft and Rotterdam. This deployment focuses on distributing long-lived entangled states between quantum memories, testing the potential to augment existing telecom networks for quantum technologies. According to Marc Hulzebos, Innovation manager at Eurofiber, “Our project demonstrates how existing fiber infrastructure can evolve to support the next generation of quantum technologies.” By integrating quantum signals with deployed fiber, the collaboration lays groundwork for interconnected quantum devices and a future quantum internet.
Entanglement-Based Network Deployed: Delft and Rotterdam Dark-Fiber Link
The newly deployed dark fiber loop physically connects Delft and Rotterdam, establishing a dedicated pathway for quantum experimentation over metropolitan distances. This closed-loop configuration, a collaboration between Eurofiber and Delft Networks, allows for bidirectional entanglement distribution and continuous testing of quantum signals in a real-world fiber environment, the company says. Unlike previous demonstrations often confined to laboratory settings, this network uses existing deployed fiber, assessing the practical challenges of scaling quantum communication beyond short distances.
The infrastructure is designed to distribute long-lived entangled states, a critical requirement for applications demanding sustained quantum correlations between distant quantum memories. Signal attenuation and synchronization represent key hurdles addressed by the project, as maintaining entanglement fidelity over extended fiber lengths requires precise control and compensation for signal loss. Researchers are actively evaluating performance metrics within the carrier-grade infrastructure, assessing the stability of entanglement distribution and its integration with existing telecom protocols.
This focus on practical constraints distinguishes the deployment from purely theoretical explorations, aiming to accelerate the transition from research and development to scalable quantum networks. “Deploying entanglement over operational telecom networks allows us to understand and address practical constraints and accelerate the transition from R&D to scalable deployment,” said Ronald Hanson, CEO of Delft Networks.
The initiative received support from QDNL Delft’s Regional Quantum Program, a consortium involving the Province of South Holland, Metropoolregio Rotterdam Den Haag and multiple municipalities. This funding emphasises a regional commitment to advancing quantum technologies and supporting collaboration between industry and emerging quantum businesses.
Eurofiber’s contribution centers on using its existing high-quality fiber optic infrastructure, demonstrating the potential to adapt current telecom networks for quantum applications without requiring entirely new cabling installations, according to the company. “By combining classical and quantum networking capabilities, we are preparing our infrastructure for a future where quantum devices become integral to communication and computation.” Delft Networks, spun out from QuTech in 2024, is applying breakthroughs in photonically integrated qubits and quantum network software to unlock real-world advantages.
The company’s work is also supported by funding from the European Innovation Council, the EU Chips JU pilot and the EU Quantum Flagship programme, highlighting a broader European investment in quantum communication technologies, the company says. The project’s success reinforces the Netherlands’ position as a leader in quantum communication innovation.
Our project demonstrates how existing fiber infrastructure can evolve to support the next generation of quantum technologies.
Marc Hulzebos, Innovation manager at Eurofiber
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