Ultralow Threshold Current Vertical-Cavity Surface-Emitting Lasers with AlAs Oxide—GaAs Distributed Bragg Reflectors

An electrically-pumped, vertical-cavity, surface-emitting laser (VCSEL) using an AIAs oxide–GaAs DBR above the AlGaAs–GaAs–InGaAs gain region and a conventional AIAs-GaAs DBR below is described. By selective oxidation, devices with current flow apertures of different areas are fabricated, and in 8-µm-square devices, threshold currents as low as 0.22 mA are achieved. Being the first electrically-pumped VCSEL to utilize the oxide-based DBR, it demonstrates that the oxide-based DBR is of sufficient quality to realize submilliampere threshold currents.