Theoretical Studies on Chaotic Semiconductor Laser Dual-directional Secure Communication System

A full-light chaotic synchronization system of external light injected semiconductor lasers with optical coupled-feedback is presented.The dynamical stable characterization of laser is analyzed,its maximum Lyapunov exponent is calculated.The system synchronous error perturbed equation is proved.Synchronous error and demodulation formulae are also theoretically demonstrated under chaotic masking encoding.And the system gradual synchronization is numerically certified and successfully simulated.Synchronization transient respond and noise effect also are analyzed.The system has an anti-disturbance ability.Chaotic analog secure communication with a sinusoidal signal of 0.2 GHz modulation frequency,chaotic digital secure communication with a digital signal of 0.2 Gb/s modulation rate and chaotic shift keying secure communication with a rate of 0.05 Gb/s are numerically simulated,respectively.The decoding character and modulation bandwidth of the system are analyzed,in particular.The system shows the good ability of robust security in time-domain and frequency-domain,so it could be used in dual-directional chaotic secure communication.The system parameter mismatch is studied to illustrate that its practical performance can be realized because synchronization can be achieved under a certain range of parameter mismatch.