TEMPERATURE-DEPENDENCE OF GAIN-GUIDED VERTICAL-CAVITY SURFACE-EMITTING LASER POLARIZATION

We show the polarization characteristics of gain-guided vertical-cavity surface emitting lasers are related to the temperature-dependent cavity optical resonance and laser gain spectral alignment. Simultaneous nearly degenerate orthogonal eigen polarization states are observed at and above lasing threshold. The partitioning of power between the linear polarization states is shown to depend on the relative spectral overlap of the cavity resonance of each state with the gain. Near the condition of cavity resonance/gain alignment, an abrupt switch in the dominant eigen polarization with a region of polarized output fluctuations is evident. Rotation of the eigen polarization directions relative to the crystal axes is also observed at temperatures where the gain is blue shifted from the cavity resonances.