CAJ | 학술논문

外腔反馈半导体激光器在合适的反馈强度下将呈现混沌态，其输出的激光混沌信号可作为物理熵源获取物理随机数序列。着重研究了外腔反馈强度对最后获取的二元码序列的随机性的影响。数值仿真结果表明，随着反馈强度的增加，外腔反馈半导体激光器输出的混沌信号的延时时间特征峰值呈现先逐渐减小再逐渐增大的过程，而对应的排列熵特征值呈现先增大、后缓慢降低的过程，即存在一个优化的反馈强度可使输出的混沌信号的延时特征得到有效抑制且复杂度高。利用NIST Special Publication 800-22软件对基于不同反馈强度下外腔半导体激光器输出的混沌信号所产生的二元码序列的随机性进行了相关测试，并讨论了反馈强度的大小对测试结果的影响。
외강반궤반도체격광기재합괄적반궤강도하장정현혼돈태，기수출적격광혼돈신호가작위물리적원획취물리수궤수서렬。착중연구료외강반궤강도대최후획취적이원마서렬적수궤성적영향。수치방진결과표명，수착반궤강도적증가，외강반궤반도체격광기수출적혼돈신호적연시시간특정봉치정현선축점감소재축점증대적과정，이대응적배렬적특정치정현선증대、후완만강저적과정，즉존재일개우화적반궤강도가사수출적혼돈신호적연시특정득도유효억제차복잡도고。이용NIST Special Publication 800-22연건대기우불동반궤강도하외강반도체격광기수출적혼돈신호소산생적이원마서렬적수궤성진행료상관측시，병토론료반궤강도적대소대측시결과적영향。
Under proper feedback strength, an external-cavity feedback semiconductor laser can operate at a chaos state, and its chaotic output can be used as a physical entropy source to generate a physical random number sequence. In this paper, we focus on the influence of feedback strength on the randomness of the obtained binary code sequence. The simulation results show that with the increase of feedback strength, the time delay characteristic peak of the chaotic signal from an external-cavity feedback semiconductor laser first decreases and then increases gradually, meanwhile, the permutation entropy characteristic value of chaotic signal first increases and then decreases gradually, namely, there exists an optimized feedback strength for obtaining the chaotic signal with the weakest time delay signature and high complexity. The randomness of binary code sequences, generated by the chaotic signal from the external-cavity feedback semiconductor laser under different feedback strengths, is tested by NIST Special Publication 800-22, and the influence of feedback strength on the test results is also discussed.