Studii privind comportarea sistemelor laser cu semiconductoare în cavități optice externe duble pentru comunicații securizate / Studies on the behaviour of semiconductor laser systems coupled with two external cavities for secure communications

This thesis makes a detailed study on the chaotic dynamics of the emission of a semiconductor laser system optical coupled with an external cavity operating in different feedback conditions determined by injection currents above the laser threshold value, double external optical cavity, operation of a chaotic coupled master-slave system in the presence of injection current modulation. Experimental studies are accompanied by the modeling and numerical simulation of the chaotic dynamics of the semiconductor laser system optically coupled with the double external cavity, operating in low frequency oscillation mode. The numerical simulation was done with Lang Kobayashi rate equations and electromagnetic field specific to semiconductor laser systems with external feedback. The results of these simulations allowed the evaluation, before performing the experiments, of the results we can obtain, depending on the experimentally controllable parameters. The approach of the chaotic dynamics of multimode emission in the visible field of double external cavity semiconductor laser systems (D-LSCE) represents an original study because the numerical models dedicated to the behavior of these systems were made only for single-mode infrared emissions. All these studies are of scientific interest due to their applications in encoding and transmitting information using chaotic optical carriers.