Temperature dependence of the null hysteresis loop in polarization switching of vertical-cavity surface-emitting lasers

This research investigated the frequency-dependent polarization switching hysteresis loop (PSHL) of vertical-cavity surface-emitting lasers (VCSELs) in constant ambient temperature. The special feature of VCSELs is the polarization switching (PS). In most case, the switching current in the rise and decline bias are not the same, and shows hysteresis. The ambient temperature was controlled in this experiment. The hysteresis loop width of polarization switching disappears as the modulation frequency is lower than a critical frequency. Experimental results show that the critical frequency dependents on the ambient temperature. Experimental data presents that the thermal effect plays a major role in the hysteresis of PS. These results greatly contribute to the understanding of the VCSEL's PSHL.