Chaos synchronization in semiconductor lasers with optoelectronic feedback

Chaos synchronization is experimentally investigated in semiconductor lasers with delayed optoelectronic feedback. Depending on the coupling strength of the driving signal to the receiver, the lasers fall into different regimes of chaos synchronization or modulation. Synchronization happens when the coupling strength to the receiver matches the feedback strength to the transmitter, where the receiver output reproduces the output of the transmitter regardless of the presence of channel distortion or an encoded message. Modulation dominates when the coupling strength is much less than the feedback strength, where the receiver output follows the driving signal. In between, there is no sharp transition between these two regimes but only a mixture of the two phenomena. Driven oscillation is not observed in this optoelectronic feedback system when the coupling strength is increased to a level higher than the feedback strength.