Communication using synchronization of optical-feedback-induced chaos in semiconductor lasers

A communication system based on the synchronization of optical chaos in semiconductor lasers is proposed. The optical chaos is generated in a single-mode semiconductor laser with external ring optical feedback. Synchronization of chaos is performed by a direct optical-injection scheme that consists of a transmitter laser with an external optical feedback and a receiver laser with optical injection from the transmitter laser. Both numerical and experimental results on synchronization of gigs-hertz chaotic signals are presented. Direct encoding of 2.5 Gbps messages on the chaotic waveform is numerically demonstrated. The bit-error rate shows a sensitive dependence on the frequency detuning.