| Recent advances in the rapidly developing field of complex networks has established the usefulness of network representations as an insightful mathematical framework for the largescale description of systems that,like the World Wide Web(WWW),road grids,and the power grids,are composed of many interacting parts.Previous research has followed two main lines:one focused on the discovery and modeling of structural properties in real biological,social and technological networks,and the other on the theoretical study of dynamical processes,such as synchronization in abstract model systems.Despite the significant insights provided by these studies,the connection between network topology and the large-scale dynamics of real systems remains largely unexplored.As a typical nonlinear system,semiconductor lasers have rich intrinsic nonlinear dynamic behavior and have great application potential in optical information processing and optical computing.It has been adopted in a variety of applications such as secure optical communication,chaotic radar,neuron-like dynamics generator,generation of high-speed random bit and photonics information processing.However,with the increasement of information network size,the existing synchronization theoretical model of simple point to point semiconductor lasers has faced a great challenge in describing the nonlinear dynamical characteristics of complex semiconductor laser networks.And it is difficult to meet the demand of secure communication network.Based on the important applications of semiconductor lasers in the field of secure optical communication,this work explores new synchronization phenomena in complex networks.Beside,we study the new synchronization mechanism in laser networks with complex topological structure and propose new method for control of synchronization among lasers.Moreover,new schemes for the concealment of time delay signature in the output of semiconductor lasers is designed.It is of great theoretical and practical significance to realize the synchronization control of some specific lasers in the network,expand the application range of semiconductor laser system in the field of secure optical communication,and further improve the security of communication.Supported by the National Natural Science Foundation of China(Chaos synchronizaiton and polarizaiton properties in mutually coupled LDs with multi-channel time-varying injection;Hig-speed random number generators based on chaotic LDs and applicaiton in communication system),the Sichuan Science and Technology Program(Study on high speed random number generator and laser chaotic communication),this thesis concentrates on the semiconductor laser networks with complex topology and mainly explores from the following aspects.Firstly,the relationship between topology and dynamics of complex network is studied to explore new synchronization phenomenon.Then on this basis of previous research,we induce the theory of complex network into the semiconductor laser systems and investigate the influence of network structure on the stability of cluster synchronization in semiconductor laser networks.Moreover,an externally drive laser is introduced to realize the control of isolated desynchronizaiton,and the relationship among the stability of different clusters for investigated.At last,we discuss the concealment of time-delay signature in different semiconductor laser systems and networks.This work will the improve the stability of all-optical communication network,and enhance the security of communication network at the same time.The innovative achievements of this thesis are:6 SCI papers as the first author are published during the doctoral study.The innovative works of this thesis are present as follows:Firstly,we discover and characterize a new phenomenon in network synchronization,which we termed IMRS.In previously identified forms of remote synchronization between two nodes,the intermediate portion of the network connecting the two nodes is not synchronized with them but generally exhibits some coherent dynamics.Our work demonstrated IMRS,which is a scenario in which two noncontiguous parts of the network are identically synchronized while the dynamics of the intermediate part is statistically and information-theoretically incoherent.This work identified mirror symmetry in the network structure as a mechanism allowing for such behavior,and showed that IMRS is robust against dynamical noise as well as against parameter changes(the size of network and the coupling strength).IMRS is important as it represents a combination of remote synchronization with chimera states.We argue that IMRS may underlie neuronal information processing and lead to network solutions for encryption key distribution and secure communication.One paper has been published:[Physical Review Letters,118(1):174102,2017].Secondly,the complex network theory is introduced into the investigation of semiconductor lasers,and a new synchronization mode-cluster synchronization(CS)is explored theoretically.It is proved that based on the inherent symmetry of network topology,a semiconductor laser network can be divided into several synchronous clusters.Lasers within same cluster can be synchronized with each other,while the dynamics of lasers between different clusters are inherent.With the inducement of root-mean-square(RMS),we can evaluate the stability of cluster synchronization quantitatively.Moreover,new patterns of cluster synchronization,i.e.,the isolated desynchronization and intertwined synchronization are presented.The relationship between the stability of different clusters are investigated systematically.Additionally,the universality of proposed result is validated with the real world network-Nepal power grid.In conclusion,the symmetry-induced cluster synchronization in the complex delay-coupled SLs networks are systematically investigated,and those results could shed light on the synchronized dynamics and chaos-based communication applications in semiconductor laser network field.One paper has been published:[IEEE Journal of Selected Topics in Quantum Electronics,25(6):1501007,2019].Thirdly,We have investigated the isolated desynchronization in VCSEL networks.An additional auxiliary VCSEL is introduced to control the synchronization state of specific VCSEL cluster.The influence of the parameters of auxiliary VCSEL on the existence of isolated desynchronization is investigated systematically.With the calculation of cross-correlation function(CCF),it is proved that the control of stable cluster synchronization is not based on injectionlocking principle,and the intrinsic symmetry of network topology is still a necessary condition for stable cluster synchronization.Additionally,it is also found that,stable cluster synchronization can also be realized by adjusting the parameters of the injected cluster.The scheme can effectively control the synchronization of any specific cluster in semiconductor laser networks and is beneficial to the expansion of optical communication network.One paper has been published:[Optics Letters,38(45):3845,2019].Fourthly,the time-delay signature concealment is investigated systematically in different semiconductor laser systems,and the numerical results have been verified by experiments.Based on the previous work,the time-delay signature suppression in mutually coupled VCSEL network with variable polarization optical injection is studied theoretically.It is shown that,with the inducement of frequency detuning between different clusters,the time-delay signature can be deducted effectively in the VCSEL network.Moreover,time-delay signature can be further suppressed with the modulation of polarization angle.This work can further improve the security of optical communication network and provide additional solutions for the concealment of delay information in the network scenarios.Three papers have been published:[Optics Express,27(23):33369,2019],[IEEE Photonics Technology Letters,24(19):1693,2012],[International Journal of Bifurcation and Chaos,27(11):1750169,2017].In summary,this thesis focus on the chaos synchronization and time-delay signature concealment in complex semiconductor laser networks.Based on the symmetrical topology theory in complex network science,we found a novel synchronization phenomenon that combines the chimera state and remote synchronization,i.e.IMRS.Particularly,IMRS has provided the theory foundation for secure optical communication network;For the semiconductor laser networks with complex topology,we realized the stable chaotic synchronization and between different laser clusters by using symmetry of network topology.We also achieved the control of stable cluster synchronization,which offers a new approach for synchronization control in complex semiconductor laser networks;In the mutually injected semiconductor laser system and mutually coupled VCSEL network with variable polarization optical injection,the timedelay signature concealment is successfully achieved,which could significantly improve the security performance of chaotic semiconductor laser networks. |
PDF Full Text Request