| A high-speed chaotic optical communication system using semiconductor lasers with optoelectronic feedback is investigated both experimentally and numerically. The nonlinear dynamics, synchronization, and communication property of the system are investigated, respectively. The lasers are found to generate different states including periodic pulsing, quasiperiodic pulsing, and chaotic pulsing with the variation in operating conditions. The system follows a quasiperiodic scenario to chaos. When two such lasers are unidirectionally coupled together, the receiver laser can synchronize to the transmitter laser if both are identical lasers under the same driving force. Reliable synchronization of chaotic pulses on the subnanosecond time scale is achieved. Other interesting phenomena such as route tracking synchronization, anticipated synchronization, and difference between synchronization and modulation are also investigated. Chaotic communication at 2.5 Gb/s is experimentally demonstrated using this optoelectronic feedback system. Different message encoding and decoding schemes are investigated and compared. Numerical simulation further proves that chaotic communication at 10 Gb/s is feasible with high-speed lasers. |
