Study of the Dynamics of Spin-Polarized Vertical Cavity Surface Emitting Lasers Using Largest Lyapunov Exponent

Polarization dynamics of spin polarized Vertical Cavity Surface Emitting Lasers (VCSELs) has been the subject of intense research work. Apart from the interesting physics involved, polarization dynamics of VCSELs offer a platform for a wide range of applications. Recently, the potential of the use of Quantum Dot (QD) VCSELs has been highlighted. Regardless of the active material, reliable resolution of the dynamics is important. Two methods are primarily used, namely Bifurcation Theory (BT) and the Largest Lyapunov Exponent (LLE). Among the two, BT is more popular within the optoelectronics community by virtue of its simplicity. The method can determine in a fast and trackable manner the kind of the nonlinear dynamics However, it cannot quantify the strength of nonlinear dynamics This is possible with the LLE method which can be beneficial in some cases where an asymmetry in the dynamics of the system might exist. Our recent work on the dynamics of spin polarized QD-VCSELs that accounts for both the effects of Ground States (GS) and Excited States (ES) has concluded that the time evolution of the ES and GS is asymmetric. This is studied here by means of LLE.