High-efficiency native-oxide-passivated high-index-contrast ridge waveguide lasers

A GaAs-based high-index-contrast ridge waveguide laser is fabricated using a self-aligned process of deep dry etching plus oxygen-enhanced wet thermal oxidation of low Al-content AlGaAs. Lasers operating at λ=813 nm (CW, 300 K) with external differential quantum efficiencies as high as 78% are demonstrated, indicating effective passivation of the directly-oxidised etched active region sidewall surface.