Dual-channel chaos laser communication system based on fiber link with dispersion compensation scheme

A model of dual-channel chaos laser communication system based on fiber transmission is proposed in this paper. The practical open-loop configuration at strong injection condition and the excellent symmetrical dispersion compensation scheme are applied in this model. The chaotic modulation (CM) and chaotic shift keying (CSK) methods are used to encrypt the message. The communication performances of both channels are evaluated by the decoding Q factor. And, further, the influences of injection power, encryption method and bit-rate of message on the performances of both channels are researched. The simulation result indicated that the optimal injection power will decrease when two channels are multiplexed compared with the single-channel case in order to balance between restraining the adjacent interfere and keeping optical field enough strong. For each channel, CSK method is better for a low bit-rate message and CM method is better for a high bit-rate. However, for the case of dual-channel communication, one channel can achieve the optimal performance at best whatever the encryption method are. It requires that different encryption methods are applied in both channels, and the optimal communication performance can be achieved for the low-speed channel encrypted by CSK method and the high-speed channel encrypted by CM.