Quantum Data Teleported Over 30km of Urban Fiber
Scientists at Deutsche Telekom and the University of Warsaw have successfully achieved quantum teleportation of weak coherent polarization states over 30km of metropolitan fiber. The breakthrough uses polarization encoding and trusted relays, providing a foundation for future quantum-safe data transmission standards. This marks a significant step from laboratory research toward urban-scale quantum network deployment.
- The experiment maintained a 99% fidelity rate for the transmitted quantum states over 17 days with only 1% network downtime, a significant improvement over previous metropolitan network demonstrations. This stability was achieved by using automatic polarization control systems to compensate for environmental disturbances like vibrations and temperature changes within the urban fiber infrastructure. - This achievement is part of Deutsche Telekom's broader quantum research strategy, which includes the 2023 opening of its Quantum Lab in Berlin. The lab is connected to a fiber-optic network of over 2,000 kilometers, linking partners throughout Germany for collaborative research. - The "trusted relay" technique used in this demonstration is a practical approach for extending the range of Quantum Key Distribution (QKD) networks with current technology. It involves intermediate nodes that are physically secured to relay the quantum key, overcoming the typical distance limitations of about 100 miles for a single quantum link. - While effective for current QKD systems, the trusted relay model has a key disadvantage: the encryption key is exposed within each relay node. The long-term goal for a general-purpose quantum internet involves replacing these with secure "quantum repeaters," an emerging technology that does not expose the key at intermediate nodes. - Standardization bodies like the European Telecommunications Standards Institute (ETSI) are actively working on developing standards for QKD to ensure the interoperability of equipment and protocols. This work is crucial for integrating quantum communications into existing telecommunications infrastructure on a commercial scale. - The University of Warsaw's Quantum Photonics Laboratory, a key partner in this research, focuses on spectral-temporal encoding for quantum information processing and is involved in building Quantum Key Distribution links in Poland. - A similar successful demonstration was recently conducted by Cisco and quantum networking startup Qunnect over approximately 17.6 km of existing fiber-optic cables in New York City, linking Brooklyn to a Manhattan data center. - The technology's ability to operate on existing commercial fiber, alongside classical data traffic, is a major step toward deployment. This avoids the need to build entirely new infrastructure for a future quantum internet.
