Unidirectionally coupled synchronization of optically injected semiconductor lasers

Three different synchronization scenarios, namely identical chaos synchronization, chaotic driven oscillation, and chaotic optical modulation, are experimentally observed for the chaotic optical fields generated by optically injected semiconductor lasers that are unidirectionally coupled. In this fully optical system, the channel signal is different from the output field of the transmitter laser by an additional injection optical field delivered by a master laser. In the case of identical chaos synchronization, the output field of the receiver is synchronized, and frequency locked, to that of the transmitter but is not synchronized to the channel signal. In chaotic driven oscillation, the output field of the receiver is synchronized, and frequency locked, to the channel signal but is not synchronized to the output field of the transmitter. In chaotic optical modulation, the output field of the receiver is synchronized, but not frequency locked, only to the channel signal. These three different synchronization scenarios are identified in the same optical-injection system under different operating conditions.