偏振旋转光反馈半导体激光混沌系统时延特征的隐藏

半导体激光混沌系统的时延特征为混沌通信攻击者重构非法接收机提供了线索，隐藏系统输出的时延特征能够提高通信的安全性。基于单模半导体激光器的理论模型，构建了偏振旋转光反馈半导体激光系统的动力学方程，利用自相关函数及时延特征峰相对高度，数值研究了该系统输出的时延特征。结果表明，在激光器合适的参数条件下，波片快轴方向在30°和60°附近一定范围内，反馈系数较小及偏置电流较大时，时延特征容易被隐藏。

Concealment of Time Delay Feature in the Polarization-rotated Optical Feedback Semiconductor Laser Chaotic System

Time delay signature of semiconductor laser chaotic system can make it possible for the communication attacter to rebuild the illegal receiver. Concealing the time delay signature can enhance the safety of the communication system. Based on the theory model of single-mode semiconductor laser, the kinetic equation is established describing laser chaotic system with polarization-rota- ted optical feedback. Time delay signature of output in this system is investigated numerically by autocorrelation function and the relative height of time-delay peaks. The results show that when parameters of laser are suitable and the fast axis of wave plate is in a certain range near 30° and 60°, smaller feedback coefficient and higher bias current are beneficial to hide the time delay signature.