Chaos Synchronization And Communication In Networks Based On Mutually Coupled Semiconductor Lasers

Secure communication has attracted much more attention with the high-speed development of the information-based society. Many secure communication schemes have been proposed and studied, among which the one based on chaos synchronization is particularly popularized. Semiconductor laser (SL) based chaos synchronization and chaos communication attracts extensive attention due to the unique characteristics of SLs such as complex dynamics, wide modulation bandwidth. During recent years, researchers have proposed many systems of chaos communication based on SLs, much of which mainly investigate unidirectional and bidirectional communication. Whereas, these systems can not satisfy the needs of a great deal of communication. Multidirectional secure communication is always highly expected.In this paper, the theories of the chaos and chaos synchronization are summarized firstly; then, chaos, chaos synchronization, and secure communication schemes based on SL are introduced; lastly, through analyzing the existed researches on the system of coupled SLs, star, ring, and mesh network systems composed of many mutually coupled SLs are presented. For these systems, the dynamical behaviors of each SL and the synchronization characteristics between arbitrary two SLs have been investigated numerically, meanwhile the secure communication performance of these systems have been analyzed. The theoretical results show that all outputs from SLs in these network systems can route into chaos under suitable coupled condition. But the synchronization characteristics are associated with topological structure:synchronization can be observed for all stars, while not synchronization between the center and stars in star network; and global synchronization can be observed in odd-numbered lasers ring networks, and clusters synchronization can be observed in even-numbered lasers ring networks; global synchronization or partial synchronization can be observed for these SLs under suitable coupled condition in mesh network. Based on the chaos synchronization in these systems, the bidirectional secure communication among multi-users can be achieved.