Minimal-post-processing 320-Gbps true random bit generation using physical white chaos.

Area of Science:

• Physics
• Optical Engineering
• Information Security

Background:

• Chaotic external-cavity semiconductor lasers (ECLs) are explored for high-speed random bit generation.
• Existing methods are limited by laser relaxation oscillation and external-cavity resonance, requiring complex post-processing.

Purpose of the Study:

• To propose and demonstrate a novel entropy source using broadband white chaos generated by optical heterodyning of two ECLs.
• To achieve high-speed random bit generation (RBG) with minimal post-processing.

Main Methods:

• Generated broadband white chaos via optical heterodyning of two ECLs.
• Utilized the white chaos spectrum and symmetric amplitude distribution for entropy extraction.
• Employed a multi-bit analog-to-digital converter (ADC) and extracted least significant bits (LSBs) for RBG.

Main Results:

• Achieved a white chaos spectrum with a 3-dB bandwidth of 16.7 GHz.
• Estimated an entropy rate of 16 Gbps with single-bit quantization, demonstrating 96% spectral efficiency.
• Generated 320-Gbps physical RBG by extracting 4 LSBs using an 8-bit ADC at an 80-GHz sampling rate.

Conclusions:

• Optical heterodyne chaos offers a superior entropy source for high-speed RBG compared to traditional ECL methods.
• Minimal post-processing is required due to the inherent properties of the generated white chaos.
• The proposed method significantly advances the capabilities of physical random bit generation.