提出了一种基于数字混沌与偏振移位键控(PolSK)技术的光保密通信系统。该系统选取几种偏振态部分或完全相同的PolSK方式,在系统不同时钟周期,发送端根据实时产生的数字混沌序列选用不同的PolSK方式调制信息,接收端利用同步的混沌序列与相应的PolSK方式解调信息。数字混沌序列的伪随机特性使得该系统的PolSK调制方式呈现无规则变化。当星座点个数不少于6且选用的PolSK方式不少于4种时,可选的PolSK组合超过1060种,系统的密钥空间庞大。用OptiSystem和Matlab软件相结合的方法进行了系统仿真,并做了一定的数值分析。仿真与分析结果表明,该光通信系统通信正常,具有较强的保密性。

An optical secure communication system based on digital chaos and polarization shift keying (PolSK) technology is proposed. Several PolSK schemes are employed, in which states of polarization are partially or totally uniform. In different cycles of the system clock, different PolSK schemes are selected in the transmitter to modulate the information according to the real-time generated digital chaotic sequences, and corresponding PolSK schemes are used in the receiver to demodulate the information according to the synchronous chaotic sequences. The pseudo-random of the digital chaotic sequences makes the PolSK modulation schemes randomly vary. When the point number of constellation is not less than 6 and number of selected PolSK schemes is not less than 4, the optional PolSK schemes exceed 1060 kinds. Therefore, the secret key space of the system is huge. Simulation is carried out with OptiSystem and Matlab softwares, and the numerical analysis is also presented. Simulation and analytical results indicate that this system works well in transmitting information and has strong anti-attack ability.