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...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.展开更多
Based on a semiconductor laser(SL) with incoherent optical feedback, a novel all-optical scheme for generating tunable and broadband microwave frequency combs(MFCs) is proposed and investigated numerically. The result...Based on a semiconductor laser(SL) with incoherent optical feedback, a novel all-optical scheme for generating tunable and broadband microwave frequency combs(MFCs) is proposed and investigated numerically. The results show that, under suitable operation parameters, the SL with incoherent optical feedback can be driven to operate at a regular pulsing state, and the generated MFCs have bandwidths broader than 40 GHz within a 10 d B amplitude variation. For a fixed bias current, the line spacing(or repetition frequency) of the MFCs can be easily tuned by varying the feedback delay time and the feedback strength, and the tuning range of the line spacing increases with the increase in the bias current. The linewidth of the MFCs is sensitive to the variation of the feedback delay time and the feedback strength, and a linewidth of tens of KHz can be achieved through finely adjusting the feedback delay time and the feedback strength. In addition,mappings of amplitude variation, repetition frequency, and linewidth of MFCs in the parameter space of the feedback delay time and the feedback strength are presented.展开更多
Interlinked positive feedback loops,an important building block of biochemical systems,can induce bistable switching,leading to long-lasting state changes by brief stimuli.In this work,prevalent mutual activation betw...Interlinked positive feedback loops,an important building block of biochemical systems,can induce bistable switching,leading to long-lasting state changes by brief stimuli.In this work,prevalent mutual activation between two species as another positive feedback is added to a generic interlinked positive-feedback-loop model originating from many realistic biological circuits.A stochastic fluctuation of the positive feedback strength is introduced in a bistable interval of the feedback strength,and bistability appears for the moderate feedback strength at a certain noise level.Stability analysis based on the potential energy landscape is further utilized to explore the noise-induced switching behavior of two stable steady states.展开更多
文摘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.
基金supported by the National Natural Science Foundation of China(Grant Nos.61178011,11204248,61475127,and 61275116)the Natural Science Foundation of Chongqing City,China(Grant Nos.2012jj B40011 and 2012jj A40012)the Open Fund of the State Key Lab of Millimeter Waves of China(Grant No.K201418)
文摘Based on a semiconductor laser(SL) with incoherent optical feedback, a novel all-optical scheme for generating tunable and broadband microwave frequency combs(MFCs) is proposed and investigated numerically. The results show that, under suitable operation parameters, the SL with incoherent optical feedback can be driven to operate at a regular pulsing state, and the generated MFCs have bandwidths broader than 40 GHz within a 10 d B amplitude variation. For a fixed bias current, the line spacing(or repetition frequency) of the MFCs can be easily tuned by varying the feedback delay time and the feedback strength, and the tuning range of the line spacing increases with the increase in the bias current. The linewidth of the MFCs is sensitive to the variation of the feedback delay time and the feedback strength, and a linewidth of tens of KHz can be achieved through finely adjusting the feedback delay time and the feedback strength. In addition,mappings of amplitude variation, repetition frequency, and linewidth of MFCs in the parameter space of the feedback delay time and the feedback strength are presented.
基金supported by the National Natural Science Foundation of China(Grants 11372017,11272024,and 11371046)the General Research Program of Science and Technology at Universities of Inner Mongolia Autonomous Region(Grant NJZY14130)
文摘Interlinked positive feedback loops,an important building block of biochemical systems,can induce bistable switching,leading to long-lasting state changes by brief stimuli.In this work,prevalent mutual activation between two species as another positive feedback is added to a generic interlinked positive-feedback-loop model originating from many realistic biological circuits.A stochastic fluctuation of the positive feedback strength is introduced in a bistable interval of the feedback strength,and bistability appears for the moderate feedback strength at a certain noise level.Stability analysis based on the potential energy landscape is further utilized to explore the noise-induced switching behavior of two stable steady states.
