双路激光混沌复用系统的混沌同步及安全性能研究

针对一种新型的双路激光混沌复用系统, 建立相应的速率方程模型, 详细分析了两个主激光器的单个参数失配、多个参数同时失配、反馈强度差异以及频率失谐对混沌同步性能的影响, 并对此复用系统的安全性能和频谱性能进行了研究. 研究结果表明: 采用参数失配方案, 通过合理选择两个主激光器的参数, 可以保证两个主激光器之间的同步性能较差而两对主从激光器间实现高品质的混沌同步, 因此满足双路激光混沌复用的条件; 两个主激光器之间的参数失配对它们之间的同步性能影响较大, 然而对配对主从激光器间同步性能的影响并不明显, 进一步说明参数失配方案的有效性和可行性. 另外, 通过自相关函数和频谱分别分析混沌复用信号的时域和频域特征, 发现双路激光混沌复用系统可提供更高的安全性.

Performance of chaos synchronization and security in dual-chaotic optical multiplexing system

Based on a novel multiplexing system of two distinct chaotic signals, the corresponding modified Lang-Kobayashi rate equations are established. The numerical investigations into the performance of chaos synchronization are carried out. In more detail, the influences of single-parameter mismatch, multi-parameter mismatch, feedback-strength discrepancy, and frequency detuning between the two master semiconductor lasers (MLs) on synchronization performance are investigated, respectively. Moreover, the security and spectrum characteristics are addressed briefly in this work. The numerical simulations show that by adopting parameter mismatch, i.e., choosing appropriate system parameters of the two MLs, the correlation between the two MLs becomes extremely low, while the matched master-slave laser pairs can achieve high-quality chaos synchronization, indicating that the condition of optical chaos multiplexing is satisfied; the parameter mismatch between the MLs has a significant influence on their synchronization quality, but no obvious influence on their synchronization quality of the matched master-slave laser pairs, which further demonstrates the validity and feasibility of the chaos multiplexing scheme. More importantly, in this paper, the multiplexed chaotic signals in the time and frequency domains in terms of autocorrelation function and power spectrum are analyzed, demonstrating that the present system could provide higher security than the single external-cavity semiconductor laser.