Quantum-enhanced AFDM: a six-dimensional encryption scheme for reliable and secure optical fiber transmission

Area of Science:

• Optical Communications
• Quantum Information Science
• Network Security

Background:

• Passive Optical Networks (PONs) face performance and security challenges.
• Existing systems like Orthogonal Frequency Division Multiplexing (OFDM) have limitations in dispersion tolerance and security.

Purpose of the Study:

• To propose and experimentally validate a quantum-enhanced AFDM PON system.
• To improve receiver sensitivity and chromatic dispersion tolerance.
• To implement a robust physical layer security scheme for PONs.

Main Methods:

• Experimental validation of AFDM signals in Standard Single-Mode Fiber (SSMF) transmissions of varying lengths (30-km, 50-km, 80-km).
• Comparative analysis of receiver sensitivity and chromatic dispersion tolerance against OFDM.
• Implementation of a six-dimensional (6-D) signal encryption scheme using true random sequences.
• Testing in a 10-km, 7-core fiber system to evaluate multi-core integration and crosstalk resilience.

Main Results:

• AFDM signals demonstrated receiver sensitivity gains of 0.5 dB, 1 dB, and 3 dB over OFDM in 30-km, 50-km, and 80-km SSMF, respectively.
• A 1-dB performance advantage for AFDM was observed in crosstalk-dominated environments.
• The 6-D encryption scheme effectively masked signals, enhancing security against brute-force attacks.
• Exceptional inter-core interference suppression and complete physical layer security were achieved.

Conclusions:

• The quantum-enhanced AFDM PON system offers superior performance and enhanced security.
• AFDM technology provides a viable solution for high-capacity and secure optical access networks.
• The proposed framework lays the groundwork for future secure optical network development.