Linear anisotropies and polarization properties of vertical-cavity surface-emitting semiconductor lasers

The polarization properties of the light emitted by vertical-cavity surface-emitting semiconductor lasers are studied by means of a four-level scheme which includes misaligned linear phase and amplitude anisotropies. First we investigate the system stability characteristics, demonstrating that upon increasing the pumping level a polarization switching may take place both from the lower- to the higher- and from the higher- to the lower-frequency states. Then we study the laser stationary states identifying the role played by nonlinear effects and demonstrating that noticeable deviations from linear behavior are induced by the simultaneous presence of misaligned phase and amplitude anisotropies with comparable magnitude.