【作者】 邱鑫；

【导师】 吴正茂；

【作者基本信息】 西南大学 ， 光学， 2008， 硕士

【摘要】 激光混沌系统具有很大的带宽、动力学行为复杂和系统对参数的高度敏感性等特点,适合于进行高速远程通信。在光混沌通信中,如何使系统在保持较好的保真性和较高的保密性成为保密通信中需要解决的关键问题,本论文对混沌同步开关及其特性进行了研究,研究结果有助于使系统在存在一定参数失配的条件下达到较好保真性与保密性。针对实验报道的光混沌同步开关现象,建立了基于半导体激光器的光混沌同步开关的理论模型。利用该模型,数值模拟了相关函数随失谐频率变化图像。结果表明:改变系统工作参量(如失谐频率),系统会在完全同步(CCS)态和广义同步(GCS)态之间发生转换,从而呈现出混沌同步开关现象。本文也数值模拟了不同外腔反馈强度和注入强度下的光混沌同步开关特性。结果表明:固定外腔反馈强度,不同注入强度下的混沌同步开关的对比度和宽度均不同;当注入强度与外腔反馈强度相同时,开关的对比度达到最大值;进一步地,当外腔反馈强度和注入强度同步增强时,混沌同步开关的对比度和宽度均单调增大。本文的研究将有助于更深入的认识光混沌同步开关机制,并为开发新型的混沌数字隐藏技术提供相关理诊基础。更多还原

【Abstract】 Laser chaotic system has many merits such as broad bandwidth, complex dynamic behavior and the highly sensitive to parameters, which are suitable for high-speed and long-distance communications. In the optical chaos communications, how to make the system better to maintain the fidelity and high confidentiality becomes a key issues to address in the secure communication. In this paper, chaos synchronization switching and its characteristics are investigated, and the results will helpful to achieve fidelity and confidentiality under the case of parameters mismatch.A theoretical model characterizing a reported experiment on optical chaos synchronization switching is presented. Based on the model, the correlation function has been simulated with change of detuning frequency. The results show that: changing parameters of system (such as frequency detuning), the system synchronization state will be switched between complete chaos synchronization (CCS) state and generalized chaos synchronization (GCS) state, thus presenting a chaos synchronization switching phenomenon. In the paper, the characteristics of optical chaos synchronization switching have also been numerically simulated for different feedback strength and injection strength. The results show that: for a fixed feedback strength, both on-off switching ratio and width of the chaos switching will vary with the injection strength changed; When the injection strength equals to the feedback strength, the on-off switching ratio will reach a maximum; Furthermore, when both the feedback strength and the injection strength are increased synchronously, both the on-off switching ratio and the width of the chaos switching will enhance monotonously. Investigations of this manuscript will contribute to better understanding the mechanism of chaos synchronization switching, and provide theoretical base for development of new data hiding technology.更多还原