Optical-communication systems based on chaos in semiconductor lasers

Chaotic optical-communication systems using semiconductor lasers are studied. The dynamics, synchronization, and message encoding and decoding are modeled and studied numerically and experimentally for two systems which are based on optical injection and delayed optoelectronic feedback of semiconductor lasers, respectively. An optically-injected single-mode semiconductor laser is a nonautonomous nonlinear system of three dynamical variables. It has phase-sensitive dynamics that follow a period-doubling route to chaos. A single-mode semiconductor laser with delayed optoelectronic feedback is an autonomous, delayed-feedback nonlinear system with only two dynamical variables, but its dimension can be very high when the delay time is large. It has phase-insensitive pulsing dynamics that follows a quasi-periodic route to chaotic pulsing. Stable synchronization for both systems are devised, modeled, and studied numerically and experimentally. Message encoding schemes for chaotic communication systems based on the concept of chaos modulation are devised and implemented for both systems to encode and decode optically transmitted messages.