Fast random bit generation with bandwidth-enhanced chaos in semiconductor lasers

Area of Science:

• Optics and Photonics
• Information Security
• Semiconductor Devices

Background:

• Semiconductor lasers with optical feedback are sources of chaotic fluctuations.
• Bandwidth enhancement of chaos is crucial for high-speed applications.
• Random bit generation is essential for secure communications and cryptography.

Purpose of the Study:

• To experimentally demonstrate random bit generation using multi-bit samples of bandwidth-enhanced chaos.
• To achieve high random bit generation rates.
• To verify the randomness of the generated bits.

Main Methods:

• Generating chaotic fluctuations in a semiconductor laser with optical feedback.
• Enhancing the chaos bandwidth up to 16 GHz by injecting into a second laser.
• Sampling the chaotic signal at 12.5 Giga samples per second (GS/s) to create an 8-bit digital signal.
• Performing bitwise exclusive-OR operations on samples and their time-delayed versions to generate random bits.

Main Results:

• Achieved bandwidth-enhanced chaos up to 16 GHz.
• Generated random bits using 1 to 6 bits per sample.
• Demonstrated random bit generation rates from 12.5 to 75 Gigabit per second (Gb/s).
• Statistical tests confirmed the randomness of the generated bit sequences.

Conclusions:

• Multi-bit sampling of bandwidth-enhanced chaos in semiconductor lasers is a viable method for high-speed random bit generation.
• The demonstrated technique offers a promising approach for secure communication systems.
• The system's performance is scalable to higher bit rates by increasing the number of bits per sample.