Advances in oxide-confined vertical cavity lasers

During the past two years significant performance advances have been achieved in selectively oxidized vertical-cavity surface emitting lasers (VCSELs), many of which have established overall benchmark records for semiconductor lasers. For example, a wall plug efficiency (at 1 nW output) of greater than 50% and threshold currents less than 10 μA have been obtained from VCSELs containing a stable and low refractive index Al-oxide formed from AlGaAs. These oxidized VCSEL structures leverage the high oxidation selectivity of Al(Ga)As and the capability of forming buried oxide layers within the epilayers of the laser. Presented is a review the advances made in device fabrication, structure and performance of selectively oxidized VCSELs.