Performance characteristics of buried heterostructure VCSELs using semi-insulating GaInP:Fe regrowth

We have fabricated GaAs-AlGaAs buried heterostructure vertical cavity surface emitting lasers, emitting at 850 mm, using semi-insulating GaInP:Fe regrowth and investigated their static properties. Lasers of different size (10-21 /spl mu/m) have threshold currents in the range 2.8-7.0 mA, and produce a maximum output power of 1.7-6.0 mW at room temperature. The variation of threshold current with device size shows that the leakage current at the regrowth interface accounts for a significant part of the injection current. In spite of this, a differential quantum efficiency in the range 20%-30% is obtained which indicates that the regrowth interface is smooth and does not introduce any significant scattering loss. Studies of the transverse mode properties suggest that the GaInP provides weak guiding, resulting in single mode operation up to an output power of 0.7 mW and a beam divergence of only 60 for lasers as large as 10 /spl mu/m.