Circular Polarization Switching And Polarization Bistability Of Optically Pumped 1300 Nm Spin Vertical-Cavity Surface-Emitting Lasers

Based on the spin-flip model, the output laser circular polarization switching (PS) and polarization bistability (PB) characteristics of 1300 nm spin vertical-cavity surface-emitting lasers (Spin-VCSEL) under optical pumping are investigated numerically. The results show that, for a certain polarization ellipticity P-p of the pump light, the pump power P-out can control the polarization ellipticity of the output light at a certain extent, and its absolute value increases with the increase of pump power. For a certain normalized pump power eta, the PS can occur between the left circularly polarized light and the right circularly polarized light of the spin-VCSEL and the PB phenomenon can be observed when P-p is scanned forward (gradually increasing) or backward (gradually decreasing). For the small eta, the bistability loop width increases to a maximum, and then decreases to 0 with the increasing eta. For a large eta, the bistability loop width shows a decreasing trend with the increasing eta on the whole. Moreover, the internal parameters such as linewidth enhancement factor a of the laser and birefringence coefficient gamma(p) of the source medium have a great influence on the PS and PB characteristics induced through the changing of P-p. In addition, the distribution of the bistability loop width is also given in the parameter space of some key internal parameters of the laser and eta.