Polarization switching in composite resonator vertical cavity lasers

We report polarization switching in a monolithic dual-resonator vertical-cavity laser. The light output from the top ion-implanted cavity under forward bias above threshold is partitioned into two orthogonal polarizations of the fundamental transverse mode. A reverse bias of sufficient magnitude applied to the bottom oxide-confined cavity causes the abrupt suppression of the dominant polarization and simultaneous emergence of the orthogonal polarization. We find that the electro-optic birefringence of the two polarizations increases with increasing reverse bias. We show that the mechanism of the polarization switch is consistent with wavelength-dependent loss from electroabsorption in the reverse-biased quantum wells of the oxide-confined cavity.