Bidirectional Chaos Communication Based On Two Semiconductor Lasers Subject To Incoherent Optical Injection Of Common-chaotic-signal

With the high-speed development of the information-based society, high-speed high-security chaos communication becomes the research focus in the communication field. Especially, semiconductor laser (SL) based chaos synchronization and chaos communication attract extensive attention due to the unique characteristics of SLs such as complex dynamics, wide modulation bandwidth, and easy to package. The limitations of the unidirectional secure communication stimulate that many SL-based bidirectional chaos communication schemes have been proposed. One type scheme, which is based on chaos synchronization between two response SLs (R-SLs) simultaneously subject to optical injection of common-chaotic-signal from a driven SL (D-SL), possesses an advantage that the rate of the transmission message is not limited by chaos pass filtering (CPF) since the decoded process does not depend on the CPF effect. At present, the relevant investigations are focus on the chaos synchronization and communication between two R-SLs induced by coherent optical injection of common-chaotic-signal from the D-SL. Previous results have shown that the chaos system based on incoherent optical injection possesses better robustness to parameter mismatches compared with the system based on coherent optical injection system.In this paper, a novel bidirectional chaos communication system based on the chaotic synchronization between two R-SLs simultaneously subject to incoherent optical injection of common-chaotic-signal from a D-SL has been proposed. In such a system, the outputs of two R-SLs are rendered into chaotic states and synchronized by incoherent optical injection. As a result, two synchronized chaos from two R-SLs can be taken as two carriers to hide two bidirectional transmission messages, meanwhile two messages can be decoded at the received terminals by the aid of synchronized characteristic of two chaos outputs from R-SLs. The influences of the intrinsic parameter mismatches between two R-SLs on the synchronization quality of the chaotic system have been investigated, and the hidden effects of the messages during transmission process and bidirectional transmission performances for two messages with2Gbit/s have been analyzed. The results show that, under proper operation condition, high-quality chaos synchronization between two R-SLs can be achieved while the cross-correlation coefficients between the two R-SLs and the D-SL are very low. The intrinsic parameter mismatches between two R-SLs will destroy the synchronization quality to a certain extent, but the effects are not severe. The two messages can be efficiently hidden in the chaotic waveforms and can be decoded satisfactorily at two receiver terminals. Finally, through analyzing the various ways which eavesdropper may be used to eavesdrop the message, the security of this bidirectional chaos communication scheme has been proved.