Wideband chaotic comb source using a weak-resonant-cavity Fabry-Perot laser diode subject to optical feedback for parallel random number generation

Currently, optical chaos comb generation primarily relies on dielectric nonlinear micro-cavities on-chip, which require a high quality-factor. This increases complexity, cost, and potential compatibility issues with photonic integration. Here, we propose and experimentally verify a novel and simplified scheme for generating chaotic combs. We utilize a weak-resonant-cavity Fabry-Perot laser diode (WRC-FPLD) connected to a single ferrule connector with physical connection to generate a wideband chaotic comb. It is possible to achieve over 70 chaotic carrier channels, covering a spectral range exceeding 40 nm. The effective bandwidth of the single channel chaotic signal reaches 15.43 GHz. The Pearson correlation coefficient between randomly selected two-channel time series is −0.0033, indicating an almost negligible level of correlation. The cross-correlation among the 15 channels in the wavelength range of 1546.4–1554.5 nm is all within 0.05, meeting orthogonality requirements and distinguishing it from traditional FPLD with external feedback. The offline random bit sequences generated by single-channel chaos have been validated using the National Institute of Standards and Technology Special Publication 800-22 Statistical Test suite, thereby confirming the practicality of our proposed scheme. Since each chaotic carrier can be used as an independent chaotic entropy source after filtering and extraction, so the data throughput of the offline random number sequence generated by this scheme is expected to reach 22.40 Tbits/s (320 Gbits/s × 70 = 22.40 Tbits/s). Furthermore, III-V-based WRC-FPLDs offer the advantage of monolithic integration, which makes them potentially capable of achieving miniaturization, cost-effectiveness, massively parallel high-speed random bit generation, and parallel chaotic LiDAR and WDM chaotic secure communication in the future.