Nonlinear dynamics of 1550nm VCSELs under external perturbations

In this paper, nonlinear dynamical characteristics of 1550nm vertical-cavity surface emitting lasers (VCSELs) subject to positive optoelectronic feedback (POEF) or polarization-preserved optical feedback (PPOF) are experimentally investigated. For the case of POEF, various nonlinear dynamical behaviors including regular pulsing (RP), quasiperiodic pulsing (QP), chaotic pulsing (CP) and mode locking (ML) have been experimentally observed and a mapping of dynamical states is presented in the parameter space of bias current and feedback strength. For the case of PPF, the characteristics of this polarization switching (PS) between two orthogonal linearly polarized fundamental modes are strongly modified. The PPOF results in the PS point shift towards lower injection current, and the region within which the two polarization modes coexist is enlarged with the increase of the PPOF strength. Under too strong PPOF levels, the PS disappears.