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Quantum Leap: 120km Secure Connection Achieved!
10 May
Summary
- Secure quantum signals transmitted over 120km fiber.
- On-demand quantum dot device enables stable encryption.
- Time-bin encoding enhances real-world robustness.
An international research team has demonstrated a stable quantum key distribution (QKD) system, achieving secure communication over 120 kilometers of optical fiber. This significant feat was accomplished using a novel on-demand telecom semiconductor quantum dot device and time-bin encoding.
The experiment involved generating quantum signals from polarized single photons converted by a quantum dot, which were then transmitted through a 120km fiber link. The system maintained stability for over six hours of continuous operation, a crucial factor for real-world applications.
This time-bin QKD system achieved a high secure key rate, suitable for encrypted messaging, with low quantum bit error rates. The researchers highlighted that time-bin encoding offers inherent stability against environmental factors like temperature and vibrations, unlike many other quantum dot-based QKD systems.
The development marks a key step towards practical, scalable quantum communication networks based on solid-state single-photon emitters. The on-demand quantum dot source's brightness and purity are ideal for intercity fiber communication, promising integration into future QKD systems.
