Qunnect has announced a metro-scale quantum entanglement swapping demonstration over deployed telecom fiber in New York City, using what it calls a commercial quantum networking system integrated with Cisco’s quantum networking software stack. Qunnect says the test validated a hub-and-spoke model intended to scale quantum networks through commercial data centers, with endpoints designed for room-temperature operation and centralized cryogenic equipment at a hub.
The demonstration ran on Qunnect’s GothamQ testbed across 17.6 km of deployed fiber connecting Brooklyn and Manhattan through QTD Systems’ data center at 60 Hudson Street. Qunnect reports record entanglement swapping rates of 1.7M+ pairs/hour locally and 5,400 pairs/hour over deployed fiber, which it says is nearly 10,000 times better than previous benchmarks using similar platforms. Qunnect also reports this as the first demonstration of polarization entanglement swapping over deployed fiber, maintaining greater than 99% polarization fidelity.
Qunnect attributes polarization stability to its Automatic Polarization Controllers (APCs), which it says continuously compensate for polarization drift in deployed fiber. The testbed used Qunnect’s turnkey Carina system, which Qunnect describes as generating entangled photon pairs, and it integrated that hardware with Cisco’s unified quantum networking software stack. Qunnect says Cisco’s software autonomously coordinated Qunnect’s Carina hardware across geographically separated nodes during the demonstration.
The companies say the architecture reduces operational coupling between nodes by avoiding a shared master laser. Qunnect says its “independent atomic sources” removed the need for a shared laser “tether,” enabling modular hub-and-spoke scaling where new endpoint nodes can be added without dedicated synchronization links to all other nodes. In performance terms, Qunnect lists a “fully automated, 24/7 operational system,” room-temperature detectors at end nodes, and cryogenic equipment concentrated at the central hub as key elements of the design.
“Entanglement swapping is a fundamental operation in the quantum internet,” said Mehdi Namazi, Co-Founder and Chief Science Officer for Qunnect. “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,” “This is a milestone the field has been waiting for, and it was proven possible by Cisco and Qunnect.”
“This milestone accelerates our quantum networking vision,” said Reza Nejabati, Head of Quantum Research at Cisco. “Our orchestration software enabled field-ready entanglement distribution and swapping—foundational capabilities for distributed quantum computing and the global quantum grid,”
Source: Qunnect
