Exploiting optical chaos with time-delay signature suppression for long-distance secure communication

The time-delay (TD) signature of the chaotic signal is an essential factor for eavedroppers and attackers to reconstruct the secure communication system. Based on three-cascaded vertical-cavity surface-emitting lasers (VCSELs) for TD signature suppression, we propose a novel long-distance secure communication system. We analyze the influence of the feedback time (i.e., the TD signature) on the security of the proposed system, and suppress the TD signatures of the outputs of the VCSELs under proper parameters. Based on chaos synchronization with TD signature suppression, we exploit the chaos masking encryption scheme for long-distance chaos secure communication. When four 10 Gbit/s messages transmit in 20 km single-mode fiber channel or 132 km SMF channel with dispersion compensating fiber, all bit error rates (BERs) keep smaller than 10^-9, and Q-factors are larger than 6, which illustrates that the proposed system effectively realizes long-distance chaos secure communication.