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

在量子密码系统中，真随机数对于科学计算、随机建模、保密通信和量子密钥分配都具有重要意义。混沌激光器为真正的随机数生成提供高质量的随机性。在基于混沌的随机数发生器中，混沌激光器的带宽决定了所产生的比特率，迄今为止所产生的比特率被限制在35 GHz左右，并且它们需要大量的信号后处理。在典型的混沌激光系统中，来自外部光反馈的附加竞争动力学对于宽带混沌输出是必不可少的。然而，由于产生的光学混沌具有时延特性，使得几乎所有的混沌激光器都不能满足不可预测、不可再现和统计无偏的特性。这归因于通过具有固定延迟时间的不同激光注入来产生混沌性质的混沌激光产生的基本构建块。其结果是，产生的混沌激光输出的时间延迟签名诱导的可预测性，这使他们从随机数产生的资格。为了克服上述瓶颈，我们提出了一种新的混沌激光产生具有很好的扩展带宽，以及没有时间延迟签名。通过采用随机周期分布的双失谐外光注入和随机的光反馈强度，所设计的混沌激光器的带宽将联合收割机的多个增益谱组合在一起，并扩展到50 GHz。特别是，通过我们提出的随机光纤光栅的随机分布式光反馈实现，以消除时间的可预测性和抑制的时间延迟签名，这将是第一次证明。所要求的50GHz信号分析仪对于表征上限范围为50 GHz的电频域中的混沌带宽以及识别时延特征抑制至关重要。该混沌激光器将及时建立一个高速真随机比特发生器，使加拿大在该领域具有竞争优势，为保密通信的实际应用铺平了道路。这种基于随机光栅的混沌激光器可用于量子通信、微波光子源和中性动力学。它为许多本地合作以及电信和生物医学仪器的学术和行业的国际合作打开了大门。

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.