Qunnect and Cisco have announced a major milestone in quantum networking, demonstrating metro-scale, high-speed quantum entanglement swapping over deployed commercial fiber infrastructure.
The demonstration, conducted on Qunnect’s GothamQ quantum networking testbed in New York City, combined Qunnect’s room-temperature quantum hardware with Cisco’s quantum networking software orchestration platform. The result represents one of the first demonstrations of entanglement swapping performed across operational telecommunications fiber in a dense urban environment.
Quantum Networking Demonstrated Across New York City Fiber
The network spanned 17.6 kilometers of commercial telecom fiber, connecting Brooklyn and Manhattan through QTD Systems’ data center at 60 Hudson Street.
Using deployed metropolitan infrastructure rather than laboratory fiber systems, the demonstration validated a scalable hub-and-spoke architecture for future quantum networks operating through commercial data centers.
According to the announcement, the experiment achieved several technical firsts in real-world quantum networking deployment.
Record Entanglement Swapping Performance
The collaboration achieved record entanglement swapping rates, including:
- 1.7 million+ entangled pairs per hour locally
- 5,400 pairs per hour across deployed metro fiber
These results represent performance improvements nearly 10,000 times greater than previous benchmarks using comparable platforms.
The system also maintained greater than 99% polarization fidelity, demonstrating stable quantum signal performance across one of the world’s most complex telecommunications environments.
Room-Temperature Quantum Hardware Enables Scalable Deployment
A key feature of the demonstration was the use of room-temperature quantum endpoints, allowing deployment without requiring cryogenic systems at every network node.
Cryogenic equipment was instead centralized at a hub location, reducing infrastructure complexity and supporting more cost-effective scaling of quantum networks.
Qunnect’s system architecture also enables independent entanglement sources that do not rely on shared master lasers between nodes. This removes a traditional physical limitation in quantum networking and allows additional network nodes to be added without dedicated synchronization links.
Integration of Hardware and Software Networking Systems
At the center of the demonstration was Qunnect’s Carina quantum networking system, which generates entangled photon pairs and stabilizes signals across deployed fiber using Automatic Polarization Controllers.
Cisco’s quantum networking software stack coordinated operations across geographically separated nodes, autonomously managing entanglement distribution and swapping throughout the network.
Reza Nejabati, Head of Quantum Research at Cisco, noted that orchestration software plays a foundational role in enabling distributed quantum computing systems and future quantum networking infrastructure.
Advancing Practical Quantum Networks
Entanglement swapping is considered a fundamental operation required for large-scale quantum networks and future quantum internet architectures.
According to Qunnect Chief Science Officer Mehdi Namazi, the demonstration shows that scalable quantum networking can operate reliably using existing metropolitan fiber infrastructure—even within highly variable urban environments.
The results provide a deployable model for future distributed quantum computing systems and secure metro-scale quantum communication networks.
A scientific paper describing the demonstration has been made available on ArXiv.
