Abstract
Electronic-controlled rounte to chaos in a quantum-well laser diode is carried out by a delayed-feedback technique. By introducing an extra delayed-feedback control term cSn(t-τ),chaotic light output can be achieved. Bifurcation diagram suggests qusi-periodicity route to chaos. In addition, a practical algorithm to calculate the Lyapunov exponents for delay differential equations has been developed. The resulets from the Lyapunov exponents also indicates chaotic behaviors. A synchronization scheme using quantum well laser diodes with delayed-feedback in optical chaotic communication is proposed. To synchronize between two identical chaotic system with different initial conditions, a drive and response system modelis constructed according to Pecora and Carroll's theory. Synthronization can be achieved for optical simplex and duplex transmissions provided that the conditional Lyopunov exponents for drive and response systems are all negative. This approach offers a key step toward the optical chaotic modulation and demodulation. Optical chaotic transmission of a digital signal is investigated by the input parameter switch using the drive-response model according to Pecora and Carroll's theory. The digital message can in the receiving end. In addition, the first conditional Lyapunov exponent of the system is shown to be directly the transmission rate. 2 Chaos 5 2.1 Formulation ........................................5 2.2 Trajectory, Poincare map and Bifurcation diagram ....6 2.2.1 Trajectory ......................................6 2.2.2 Poincare map ....................................6 2.2.3 Bifurcation diagram .............................7 2.3 Lyapunov expinents ..................................8 3 Synchronization 11 3.1 Formulation .......................................11 3.2 Synchronization in simplex transmission ............11 3.3 Synchronization in duplex transmission .............13 4 Optical digital communication 14 5 Conclusion 17