反馈强度调制增强混沌光通信的保密性

注入锁定式光混沌同步通信系统对收发机的参数失配有较大的容忍度，这在一定程度上降低了信息的安全性.提出采用反馈强度的调制来提高系统的保密性.数值模拟分析了调制前后系统提取信号质量的变化，以及收发机调制的速率失谐、延时对提取信号质量的影响.研究发现：仅在发射机增加反馈强度调制后，同步性恶化、误码率增大两个数量级，无法提取信号；而在接收机引入相同的调制后，系统同步性及误码率得到恢复.此外，收发机的反馈强度调制速率失谐和延时范围分别在±5 MHz和±0.1倍调制周期时，信息提取质量较高.反馈强度调制能够有效地增强传统混沌通信系统的保密性. 关键词： 反馈强度 调制 混沌通信 保密

Modulation of feedback strength to enhance the security of chaos optical communication system

There is a high tolerance on parameters mismatch between transmitter and receiver in the chaos communication system based on injection locking synchronization, so to a certain extent, the information security has been reduced. We propose the synchronous modulation of feedback strength to improve the system security. The change of signal extraction quality after modulation is studied numerically, and the effects of modulation rate detuning and modulation delay time on signal extraction are analyzed too. The research results indicate that the synchronization of the original system is destroyed and the bit error rate increases by two orders of magnitude when the transmitter feedback strength is modulated. The information can not be recovered unless the receiver uses the same modulation. Furthermore, the results also show that high quality information could be obtained when rate detuning and delay time are in the range of±5 MHz and±0. 1 times the modulation cycles, respectively. All of these prove that modulating the feedback strength can enhance the security of chaos communication efficiently.