Time delay signature suppressed broadband chaotic laser for high-speed all-optical true random number generator

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Truly random numbers are important for scientific computation, stochastic modeling, secure communications and quantum key distribution in quantum cryptography systems. Chaotic lasers provide high quality randomness for truly random number generation. In chaos-based random number generator, the bandwidth of the chaotic laser dominates the generated bit rate which is limited around 35 GHz to date and they require significant post-signal processing. In typical chaotic laser system, additional competition dynamic from external optical feedback is essential for a broadband chaotic output. However, the unpredictable, unreproducible and statistically unbiased features cannot be met by almost all of chaotic lasers due to the time delay signature in the generated optical chaos. This is attributed by the basic building block of chaotic laser generation via different laser injection with a fixed delay time to create chaotic nature. As a result, the time delay signature of the generated chaotic laser output induced the predictability, which disqualified them from random number generation. To overcome the above-mentioned bottleneck, we propose a novel chaotic laser generation with a well extended bandwidth as well as free from time delay signature. By dual detuning external light injections with distributed random periods with randomized optical feedback strength, the bandwidth of the proposed chaotic laser would combine the multiple gain spectra and be well extended up to 50GHz. In particular, random distributed optical feedback through our proposed random fiber grating are implemented to remove the temporal predictability and suppress the time delay signature, which will be demonstrated for the first time. The requested 50GHz Signal Analyzer is crucial for the characterization of the chaos bandwidth in electrical frequency domain with the upper limit range of 50 GHz, as well as the identification of the time delay signature suppression. The proposed chaotic laser would build up a high speed true random bit generator timely to give Canada competitive edge in this field, paving a way for practical application in secure communication. This random grating based chaotic laser can be used for quantum communication, microwave photonics source and neutral dynamics. It opens doors for many local collaboration, as well as international collaborations in academic and industry of telecom and biomedical instrumentation.