High speed prototype quantum key distribution system and long term field trial

Area of Science:

• Quantum Information Science
• Network Security
• Applied Physics

Background:

• Information security in communication networks is a critical global challenge.
• Quantum Key Distribution (QKD) offers unique security features, enabling intrusion detection and preventing information leakage.
• Existing QKD systems face limitations in speed and real-world deployment robustness.

Purpose of the Study:

• To report a record high bit rate prototype Quantum Key Distribution (QKD) system.
• To demonstrate the system's performance and robustness in a metropolitan fiber network.
• To provide a comprehensive security analysis including finite key size effects and decoy states.

Main Methods:

• Deployment of a compact, robust, and automatically stabilized QKD prototype.
• Operation over a standard 45 km metropolitan telecommunication fiber link in Tokyo.
• Utilized an efficient QKD protocol with decoy states and finite key size analysis.

Main Results:

• Achieved a total of 878 Gbit of secure key data over a 34-day period.
• Sustained a record high key rate of approximately 300 kbit/s.
• Demonstrated reliable key distribution across diverse weather conditions with a quantified key failure probability of ε = 10⁻¹⁰.

Conclusions:

• The prototype QKD system represents a significant advancement in high-speed, secure communication.
• The system's robustness and performance in a real-world metropolitan network highlight its practical applicability.
• The security analysis confirms the system's reliability for secure key distribution.