Insider Brief
- Qunnect and Cisco Systems demonstrated metro-scale entanglement swapping over 17.6 km of deployed fiber in New York City using a commercial quantum networking system.
- The trial, conducted on Qunnect’s GothamQ testbed, achieved reported swapping rates of 1.7 million pairs per hour locally and 5,400 pairs per hour over deployed fiber while maintaining greater than 99% polarization fidelity.
- The system combined Qunnect’s room-temperature hardware and independent entanglement sources with Cisco’s quantum networking software to validate a scalable hub-and-spoke architecture for distributed quantum networks.
PRESS RELEASE — Qunnect today announced the first entanglement swapping demonstration of its kind over deployed metro-scale fiber using a commercial quantum networking system. The demonstration, which achieved record entanglement swapping rates, combined Qunnect’s room-temperature quantum hardware with Cisco’s quantum networking software stack. This milestone brings practical quantum networks closer to scalable deployment, validating a new spoke-and-hub model for scaling quantum networks through commercial data centers.
To validate this model, the companies conducted a landmark demonstration on Qunnect’s GothamQ testbed which runs throughout New York City, achieving several firsts. The network spanned 17.6 kilometers of deployed telecom fiber connecting Brooklyn and Manhattan through QTD Systems’ data center at 60 Hudson Street. The scientific paper is available on ArXiv.
The collaboration achieved record swapping rates of 1.7M+ pairs/hour locally and 5,400 pairs/hour over deployed fiber – nearly 10,000 times better than previous benchmarks using similar platforms. As the first demonstration of polarization entanglement swapping over deployed fiber, the system maintained >99% polarization fidelity. These results demonstrate the integrated system can operate reliably in one of the world’s most demanding urban environments, providing a deployable blueprint for distributed quantum computing and secure metro-scale quantum networks.
“Entanglement swapping is a fundamental operation in the quantum internet. Today, we not only broke the record for rate and scalability, we did so in New York City using some of the noisiest, most chaotic fiber on Earth,” said Mehdi Namazi, Co-Founder and Chief Science Officer for Qunnect. “This is a milestone the field has been waiting for, and it was proven possible by Cisco and Qunnect.”
Key Performance Milestones:
- High Throughput: Record swapping rates of 1.7M+ pairs/hour (local) and 5,400 pairs/hour (deployed).
- Signal Stability: Maintaining ultra-high quality entanglement across all nodes using a fully automated, 24/7 operational system.
- Cost-Effective Architecture: End nodes utilized room-temperature detectors, concentrating cryogenic equipment solely at the central hub to significantly reduce the cost of network scaling.
- Untethered Scalability: Independent entanglement sources require no shared lasers, allowing for modular network expansion.
At the center of this integration is Qunnect’s turnkey Carina system, a breakthrough technology capable of generating entangled photon pairs [LINK]. To maintain signal integrity, Qunnect’s Automatic Polarization Controllers (APCs) [LINK] continuously compensate for polarization drift—a persistent challenge in deployed fiber that has historically limited real-world networking.
These technologies were integrated with Cisco’s unified quantum networking software stack [LINK] for the demonstration. Functioning as a “Digital Air Traffic Controller” for the city-wide network, the software autonomously coordinates Qunnect’s turnkey Carina hardware across geographically separated nodes.
“This milestone accelerates our quantum networking vision. Our orchestration software enabled field-ready entanglement distribution and swapping—foundational capabilities for distributed quantum computing and the global quantum grid,” said Reza Nejabati, Head of Quantum Research at Cisco.
Quantum networks today are often constrained by a complex physical “tether,” relying on a shared master laser to connect all nodes. By using Qunnect’s independent atomic sources, the experiment removed the need for nodes to be physically “tethered” by shared lasers. This decoupling of nodes allows for a scalable hub-and-spoke architecture for quantum networking, enabling new endpoint nodes to be added without dedicated synchronization links to all other nodes. This achievement serves as a first proof point in our journey toward practical, entanglement-based quantum networks, laying the foundation for distributed quantum computing.
