Accelerated secure key distribution based on localized and asymmetric fiber interferometers.

Area of Science:

• Quantum Information Science
• Optical Communications
• Cybersecurity

Background:

• Secure key distribution is crucial for modern communication networks.
• Existing methods face challenges in terms of speed, cost, and security against sophisticated attacks.
• Optical fiber infrastructure offers a promising channel for secure key exchange.

Purpose of the Study:

• To develop and demonstrate a novel approach for secure key generation and distribution over optical fiber.
• To enhance the security and efficiency of key exchange protocols.
• To leverage existing optical fiber infrastructure for practical quantum key distribution.

Main Methods:

• Utilized Mach-Zehnder interferometers (MZIs) for key generation by converting environmental noise into random optical signals.
• Implemented a novel combination of wideband optical noise and asymmetric MZI structures for secure transmission.
• Experimentally demonstrated the system over a 10 km optical fiber link.

Main Results:

• Achieved a key generation rate of 502 bit/s.
• Demonstrated successful key exchange with a low bit error rate of approximately 0.3%.
• Security analysis confirmed protection against various attacks, including active intrusion.

Conclusions:

• The proposed system offers a reliable and cost-effective solution for secure key establishment.
• Localized MZIs improve key generation rates by a factor of 5.7 and enhance robustness against attacks.
• The technology is compatible with existing optical fiber communication infrastructure, paving the way for practical implementation.