光纤中的色散和非线性效应对混沌同步的影响

Influences of chromatic dispersion and nonlinearity in the fiber on the chaotic synchronization

基于描述光反馈半导体激光器的动力学以及信号在光纤信道中传输的理论,研究了光纤中色散和非线性效应对混沌信号传输以及发射和接收激光器的混沌同步特性的影响,目的是为远程光纤混沌保密通信提供理论指导。数值模拟结果表明:光纤非线性效应只影响信号的位相,不会影响混沌信号的强度;光纤色散将使混沌信号发生严重变形,影响混沌系统的同步性能:通过在接收器的前端放置放大器以补偿光纤的损耗,信号经过200km的色散位移光纤传输后,发射和接收激光器输出混沌信号的关联系数仍可达到0.99,即系统可达到很好的同步性能。

In order to supply a theoretical guide for chaotic telecommunication, the influences of the chromatic dispersion and nonlinearity in fiber on the chaotic synchronization have been investigated based on the theoretical models used to describe the dynamics of semiconductor laser subjected to the external optical feedback and signal transmission in fiber channel. The numerical simulation results show that, the fiber nonlinear effect is responsible for the phase varying of chaotic signal and do not affect the amplitude of the chaotic signal; due to chromatic dispersion, the amplitude characteristics of chaotic signal are distorted significantly and the system synchronization quality will be impaired; after propagating 200 km in dispersion shifted fiber, a desirable system chaotic synchronization with a synchronized coefficient 0.99 can be achieved by adopting a amplifier before the received laser to compensate the fiber loss.