Thesis (M.Sc.) - Cairo University - National Institute of Laser Enhanced Sciences - Department of Lasers Applications of in Engineering

Security is a crucial demand in optical communication systems. Chaotic communication systems, in which the encryption is held on the physical layer, provide a high security level. Chaotic communications require a pair of synchronized chaotic laser diodes that can be used as a transmitter-receiver pair. Our main purpose, in this work, is to enhancement the performance of chaotic communication system by applying chaotic multiplexing will external optical system. To fulfill the main purpose it is required to study the chaotic behavior of semiconductor laser diodes, at different synchronization schemes. Some methods used to generate chaos using a laser diode, such as optical feedback, external optical injection and optoelectronic feedback, are first discussed in detail. To adequately describe the temporal behavior (dynamics) of a chaotic laser diode, the amplitude and phase of the laser electric field together with the density of charge carriers inside the laser cavity must be obtained. Thus we developed a numerical algorithm to simulate these dynamics, which depend on the method of chaos generation.

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