Mode hopping and polarization switching of mutually coupled vertical-cavity surface-emitting lasers

We perform a theoretical study on the polarization-resolved compound lasing mode (CLM) of two mutually coupled vertical-cavity surface-emitting lasers (VCSELs). Different solutions of CLMs are derived though stability analysis of the spin-flip model. The dynamical evolvements of CLMs with the existence of polarization degrees of freedom are also charactered. The most stable CLM with the smallest carrier density tend to be excited, since the gain needed for this mode to emit is the lowest. In the given system, varying values of injection rate or birefringence, etc., will change the generation of the preferred CLMs in the two polarization directions, and thus influence the polarization switching (PS) characteristics. Thus, hoppings between CLMs are also companied by PSs. Through mapping of average power in the parameter space, the influences of coupling rate and anisotropy parameters (linear dichroism and linear birefringence) on PS and hopping between CLMs are discussed.