激光器自发辐射噪声对混沌光通信系统的影响

Effects of spontaneous emission noise in semiconductor lasers on chaotic optical communication systems

构建了基于外光反馈的混沌光通信系统模型,通过引入Langevin噪声源,建立了包含自发辐射噪声特性的主从式速率方程.利用所得数学模型,研究了系统中可能存在的两类同步:全混沌同步和普通注入锁模型混沌同步;分析了两端激光器自发辐射噪声对此二类同步以及系统收发两端混沌信号的影响;最后,以2·5Gb/s伪随机数字调制下的混沌掩蔽方式为例,介绍了系统的加/解密过程以及噪声对系统解码性能的影响.

A chaotic optical communication system based on external optical feedback is constructed. By introducing the Langevin noise sources, the master-slave rate equations including spontaneous emission noise characteristics arc deduced. Utilizing the obtained mathematical model, two kinds of possible chaos synchronization in the system, i. e. complete chaos synchronization and generalized mode-locking chaos synchronization, are studied. The effects of the spontaneous emission noises of the two lasers on the two types of synchronization as well as the chaotic outputs of the transmitter and receiver are discucsed. Finally, for a sequence of pseudorandom digital bits at 2.5Gb/s bit rate, the encoding/decoding process basing on chaotic masking method is presented, and the effects of noise on decoding performance are examined.