Eurofiber has paired with quantum networking company Delft Networks to deploy dark fiber that connects Delft and Rotterdam, in the Netherlands.

Fiber firm Eurofiber confirmed that it has completed the successful deployment of entanglement-ready dark fiber connecting Delft and Rotterdam in a closed loop configuration.

The company said that the infrastructure is designed to "test and validate long-range quantum connections over existing deployed fiber," which it claims is a significant step toward the realization of a future quantum Internet.

The deployment leverages Eurofiber's fiber optic infrastructure along with Delft Networks’ advanced quantum networking expertise, and aims to prepare for the distribution of long-lived entangled states between quantum memories separated by metropolitan distances.

Eurofiber notes that the integration of quantum signals with deployed fiber allows for the exploration of how existing telecom networks can be augmented to support fundamentally new levels of privacy, trust, and coordination.

The aim of the deployment is to look at how effectively entangled quantum states can be distributed across a conventional network.

As for quantum entanglement, it's described by Eurofiber as a "phenomenon that enables generation of intrinsically secure correlations and fast coordination between distant nodes.

This allows for a new generation of machines – quantum computers and sensors – to be linked in a network providing significant performance boosts. This entanglement is seen as the foundational capability for a broader class of quantum technologies, which includes distributed quantum computing, ultra-precise sensing, and time synchronization using quantum clocks.

According to Eurofiber, the Delft–Rotterdam loop "serves as a real-world testbed for evaluating performance, stability, and scalability of entanglement distribution across operational fiber networks."

The purpose of this project, it adds, is to focus on challenges such as signal attenuation, synchronization, and integration into carrier-grade infrastructure. 

“Our project demonstrates how existing fiber infrastructure can evolve to support the next generation of quantum technologies,” said Marc Hulzebos, innovation manager at Eurofiber. “By combining classical and quantum networking capabilities, we are preparing our infrastructure for a future where quantum devices become integral to communication and computation.”

Ronald Hanson, CEO, Delft Networks, added: “Deploying entanglement over operational telecom networks allows us to understand and address practical constraints and accelerate the transition from R&D to scalable deployment.”

Funding support for the project has come from QDNL Delft’s Regional Quantum Program, which involves the Province of South Holland, Metropoolregio Rotterdam Den Haag, and the municipalities of Delft, Leiden, Rotterdam, and the Hague.

Delft Networks was spun-out from QuTech at TU Delft in 2024 to build deployment-ready full-stack quantum networks. The company is supported by funding from the European Innovation Council, the EU Chips JU pilot “Photonics 4 Quantum,” and the EU Quantum Flagship program “Quantum Internet Alliance."

Eurofiber operates a 77,500km fiber network which spans the Netherlands, Belgium, Luxembourg, France, and Germany, alongside eight data centers in the Netherlands. It acquired two in 2024, alongside the purchase of Bytesnet.