设计了一种新型的闭环双向三激光器混沌保密通信系统,驱动激光器基于延时外光反馈,两个参数完全相同的响应激光器在自身延时反馈和驱动激光器的驱动下实现混沌同步。建立了相应的理论模型,研究了系统的分岔特性、同步性以及内部参数失配对其同步性能的影响,并与不含自身光反馈的开环系统进行了比较。研究结果表明,当系统参数满足一定条件时,两个响应激光器的关联极值接近于1,而驱动激光器和响应激光器的相关性很小。与开环系统相比,该系统的载波带宽拓宽了约1.99GHz,对参数失配比较敏感并具有更好的保密性能。 A new type of closed-loop bi-directional three-laser chaotic secure communication system is designed. The driving laser is based on time-lapse extrinsic optical feedback. Two identical response lasers realize chaos synchronization driven by their own delay feedback and driving laser. The corresponding theoretical model is established and the influence of system bifurcation characteristics, synchronization and internal parameter mismatch on the synchronization performance is studied. The results are compared with the open-loop system without self-optical feedback. The results show that when the system parameters meet certain conditions, the correlation extremum of the two response lasers is close to 1, and the correlation between the driving lasers and the response lasers is very small. Compared with the open-loop system, the system has a wider carrier bandwidth of about 1.99GHz, is more sensitive to parameter mismatch and has better confidentiality.