Security-Enhanced Bidirectional Communication Based on A Long-Distance Chaos Synchronization System with Double Optical Feedback

A security-enhanced bidirectional chaotic secure communication system is proposed and numerically investigated. In which, the high-quality chaos synchronization between two response lasers (RLs) is achieved via the common chaos signals injection from a driving laser (DL) with double optical feedback (DOF). The simulated results show that, the time delay signature (TDS) of the driving chaotic signals from DL with DOF is greatly weakened under suitable operation conditions. Two RLs can generate chaos signals with low TDS and broad bandwidth, and the high quality chaos synchronization between two RLs can be achieved while the synchronization quality between DL and any one of RLs is extremely bad, which can enhance the security of messages transmission in this proposed system. Using the synchronized chaos output signals from two RLs as chaos carriers and chaos masking (CM) encoding method, the bidirectional 10 Gb/s image messages transmission can be successfully realized.