Submilliamp vertical-cavity surface-emitting lasers with buried lateral-current confinement

Lateral current confinement of intracavity contacted 0.98 μm vertical cavity surface emitting lasers has been achieved by inserting a 50 nm thick n-type GaAs current blocking layer into the p-doped cladding. Epitaxial regrowth by solid source MBE is used to bury the current confining layer in the cavities. Threshold currents of 0.78 mA, optical output powers of 1 mW and external quantum efficiencies of up to 15% are measured. The lateral current injection via the top p-type cladding leads to low voltages at threshold of 1.78 V.