Chaotic Spiking and Multiscroll Attractors in Semiconductor Laser by Optical Feedback

Abstract

In this thesis we present numerical investigation of nonlinear dynamics of a semiconductor laser subjected optical delay feedback. The investigation performed based on numerical simulation of Lang-Kobayashi model over wide range of optical feedback strength value using Matlab 7 packages software. The results show that under small, moderate and high optical feedback strength semiconductor laser output power goes different dynamical regimes involving steady state, periodic, mixed modes and chaotic spiking. These dynamics analyzed by time series and their FFt power spectrum with phase space trajectory(Attractors). The bifurcation diagram is drawn as a function of optical feedback strength. Chaos synchronization in unidirectional coupling scheme numerically presentedunderline the significance of symmetry and asymmetry of optical feedback strength and initial conditions. This work also proposed a novel numerical investigation for generating and controlling multiscroll attractors in semiconductor laser dynamics by direct current modulation. Dynamics characterized by a transition of fixed point attractor, mixed modes,chaotic spiking. The complicated dynamical behavior performed at constant optical feedback strength and variable solution time interval shown that how to increase the number of scroll from one to 1D 10 scroll attractors. These complex behaviors may be used in secure optical communication and optical networks.