Frequency response of current-driven polarization modulation in vertical-cavity surface-emitting lasers

We present an experimental study of the current-driven polarization modulation properties of vertical-cavity surface-emitting Lasers (VCSELs). Some VCSELs exhibit a high-contrast polarization flip for a particular value of pump current. By modulating the current around this value we measure the critical modulation amplitude necessary to force current-driven polarization switching as a function of the modulation frequency. We thus obtain the polarization modulation frequency response, which shows the same cut-off frequency as the thermal frequency response. This indicates the necessity to incorporate a temperature-dependent variable in realistic models that describe the polarization behavior of these VCSELs.