利用耦合时延增强激光混沌系统安全性能研究

安全性是混沌通信中的重要问题。基于一个外光反馈半导体激光器驱动两个互耦合激光器的混沌通信系统,研究激光混沌系统中反馈时延与耦合时延特征,并应用龙格-库塔法进行动态仿真。重点分析了当调节一些可控参数(耦合时延和驱动强度)时,能够改变两耦合激光器输出自相关函数中反馈时延和耦合时延幅值的差异,以此掩藏反馈时延,从而得出更优载波。仿真结果说明利用耦合时延可以增强激光混沌系统的安全性。最后给出了在优化载波后系统同步质量的讨论。

Investigation on Security Enhancement of Chaotic Optical Communication Systems via Coupling Delay

The security issue is of vital importance in chaos-based communications. The characteristics of feedback delay and coupling delay in chaotic optical communication systems has been numerically studied, based on a chaos-based communication system composed of two mutually coupled semiconductor lasers driven by an external cavity semiconductor laser. Numerical simulation of the model is established with the Runge-Kutta method. The emphasis has been devoted to the following analysis: by adjusting some controllable parameters (coupling delay and injection strength), one can reasonably change the discrepancy between the amplitudes of feedback delay and coupling delay in autocorrelation function for the mutually coupled semiconductor lasers output. For this reason, the feedback delay is effectively concealed, and thus a better chaotic carrier can be obtained. More importantly, our numerical results demonstrate that the coupling delay is able to be employed to improve the security of chaotic optical communication systems. Finally, the discussion of synchronization quality of the dedicated system, under the optimized chaotic carrier circumstance, is given.