激光混沌通信中半导体激光器接收机对高频信号的滤波特性

High frequency message filtering characteristics of semiconductor laser as receiver in optical chaos communications

数值研究了基于半导体激光器的混沌通信系统中构成混沌同步的接收半导体激光器对高频信号的滤波特性.分析了闭环结构的接收机对不同频率、不同幅度的加载信号的提取能力.研究发现,混沌保密通信系统对传输信号的提取能力与信号的频率有关.当信号频率较低时,闭环结构的接收机对信号的滤波效果较好;当信号频率接近半导体激光器的弛豫振荡频率时,接收机的滤波效果较差.分析结果同时表明,混沌保密通信系统中接收机对传输信号的提取质量不仅与实现混沌同步的两激光器的同步质量有关,而且依赖于传输信号的幅度.

The high frequency message filtering characteristics of the semiconductor laser which act as a receiver are numerically simulated in a scheme of closed-loop optical chaos communications system. Both transmitter and receiver are realized by semiconductor lasers subject to strong optical injection. We examined the filtering properties of semiconductor laser with modulation message with different frequencies and amplitudes. The results demonstrate that the filtering effectiveness of the semiconductor laser receiver is higher for low frequency message and decreases as the message frequency approaches the relaxation oscillation frequency of the semiconductor laser. The quality of message recovery in such systems is shown to depend not only on the synchronization quality but also on the difference in amplitude of the message in the transmitter and receiver outputs.