Abstract:
Chaotic dynamics are at the center of multiple studies to perfect encrypted
communication systems. Indeed, the particular time evolution nature of chaotic
signals constitutes the fundamentals of their application to secure the optical
communications. The information coded on the carrier wave can be extracted with
knowledge of the system dynamic evolution law.
The work presents the implementation of experimental chaos generation
systems by means of electro-optic feedback of the semiconductor laser. The output
photocurrent of the optical receiver is amplified and reinjected as a feedback to the
semiconductor laser source. The injected feedback photocurrent produces a chaotic
behavior in the laser output.
The change of the chaotic series and its jump from chaotic to periodic form
depends on the initial operation condition of the laser diode and on the
amplification of the injected feedback photocurrent. The chaotic signal has been
used as a carrier for data transmission, the phase masking technique was used
during the work. The data (message) signal was injected with the chaotic signal.
Finally, two of the chaotic laser systems have been established to find the
synchronization between two chaotic attractors. This step was done in order to
extract the encoded message via the chaotic laser system.
