High-index-contrast ridge waveguide laser with thermally oxidised etched facet and metal reflector

A novel GaAs-based high-index-contrast ridge waveguide quantum well heterostructure laser is demonstrated, which features an etched and wet thermally oxidised rear facet with a deposited metal mirror suitable for wafer scale integration. The self-aligned fabrication process utilises a single deep etch step and oxygen-enhanced non-selective wet oxidation of the AlGaAs heterostructure ridge sidewall and the entire exposed facet, including the waveguide core region composed of low-Al content AlGaAs material not readily oxidised by conventional techniques. Singlemode devices exhibiting thresholds as low as 20 mA at λ=808 nm are demonstrated.