Cisco detailed a metro-scale quantum networking test on deployed New York City telecom fiber in a March 19 blog post by Vijoy Pandey, Senior Vice President, Outshift by Cisco, describing a 17.6-kilometer link between Brooklyn and Manhattan that moved entanglement-based networking out of the lab and onto real operating infrastructure.
The demonstration, conducted with Qunnect, New York University, and QTD Systems, validated an entanglement-based quantum network across 17.6 kilometers of standard telecom fiber connecting three nodes between Brooklyn and Manhattan, including a route through 60 Hudson Street. Cisco said the test showed that quantum networking can operate in a live metropolitan environment on existing carrier infrastructure rather than only in tightly controlled laboratory settings.
Cisco said the system achieved entanglement swapping rates of more than 5,400 pairs per hour over deployed fiber and 1.7 million pairs per hour in local operation, while maintaining polarization fidelity above 99%. The company presented those results as a major gain over prior experimental efforts and as evidence that the technology is moving closer to commercially relevant infrastructure.
A key part of the demonstration was the separation of hardware from the protocol, control, and orchestration layer. Qunnect supplied the entanglement hardware, while Cisco’s software automated entanglement distribution and measurement coordination across the three sites. Cisco said the platform synchronized millions of photon detection events with picosecond-level accuracy using the White Rabbit timing protocol.
Cisco also argued that the test broke from the shared-laser model that has constrained many previous quantum networking experiments. Instead, the company said the results support a more scalable hub-and-spoke architecture, with specialized cryogenic equipment concentrated at a central hub and lower-cost room-temperature hardware deployed at the network edge. That design could simplify expansion and reduce the cost of adding new nodes.
- Cisco, Qunnect, NYU, and QTD Systems demonstrated entanglement-based quantum networking over 17.6 kilometers of deployed telecom fiber in New York City.
- The network connected three nodes between Brooklyn and Manhattan and included 60 Hudson Street.
- Cisco reported entanglement swapping rates above 5,400 pairs per hour over deployed fiber and 1.7 million pairs per hour locally.
- The system maintained polarization fidelity above 99% in the metro deployment.
- Cisco used a software-defined approach, combining Qunnect hardware with Cisco’s protocol, control, and orchestration stack.
- The company used the White Rabbit timing protocol to coordinate photon measurements with picosecond-level accuracy.
“This experiment is the latest milestone in that journey, and it proved that our approach works with real fiber, in a live metropolitan environment, on infrastructure that already exists,” wrote Vijoy Pandey.
