Nonlinear switching and modulational instability of wave patterns in ring-shaped vertical-cavity surface-emitting lasers

摘要

We have explored theoretically and experimentally the steady-state transverse light fields emitted from ring-shaped lasers, specifically, those from vertical-cavity surface-emitting lasers (VCSELs). We saw the switching on of patterns of increasing spatial frequencies as a function of pump parameter. Furthermore, we were able to identify the mechanism for such an evolution as geometrical modulational instability within the nonlinear cavity. Other mechanisms such as the conventional gain-loss balance had no effect on the ring configuration that was modeled. The experiments with annular VCSELs gave results that matched the theoretical predictions well, although other mechanisms not considered in our model, such as carrier diffusion, took place in the experimental devices. We conclude that the nonlinear mechanisms presented here can be regarded as limiting cases in the interpretation of more-complex functions, such as patterns, modes, and filamentation switching, in VCSELs. (C) 2002 Optical Society of America. [References: 29]