延时反馈光电振荡器是高速混沌保密通信系统产生光混沌信号的重要方案。通过Hopf分岔分析,详细研究了延时可变光电振荡器通往混沌的三条典型路径(激变、周期和准周期振荡及“breather”振荡)及其特性。通过仿真发现,随着延时的增加,输出信号的复杂度增加;当延时足够大时,在一定时间范围内出现周期脉冲现象。另外,相图突变的临界点可能是由滤波器引起的,但在临界点附近信号的复杂度变化不大。

An optoelectronic oscillator with time delay varying feedback is an important means for generating laser chaos signals in a high speed optical chaos security communication system. Three typical routes to laser chaos (cataclysm, periodic and quasi periodic oscillations, and ‘breather’ oscillations) and their characteristics are investigated in detail through analyzing the Hopf bifurcation behaviors. The simulation shows that with the increase of time delay, the complex degree of the output signal increases, and when the time delay is large enough, there occur periodic pulse phenomena within a limited time range. In addition, there exists a critical point caused possibly by the filer, at which the phase diagram changes suddenly, but the complex degree of the output signal does not change obviously.