Native-oxide-confined high-index-contrast λ = 1.15   μ m strain-compensated InGaAs single quantum well ridge waveguide lasers

High performance native-oxide-confined high-index-contrast (HIC) ridge waveguide (RWG) diode lasers are fabricated in a strain-compensated In 0.4 Ga 0.6 As single quantum well structure by employing a deep dry etch plus nonselective O 2 -enhanced wet thermal oxidation process. The thermal native oxide grown on the etch-exposed RWG sidewalls of the Al 0.74 Ga 0.26 As waveguide cladding layers and GaAs core with GaAsP-InGaAs quantum well provides both strong optical and electrical confinements for the active region. Due to a smoothing of sidewall roughness by the O 2 -enhanced oxidation, the lasers exhibit a low internal loss in α i = 7.2 cm − 1 for a w = 7.2 μ m narrow stripe HIC RWG structure, only 53% larger than that of w = 87.2 μ m broad-area devices, enabling their room temperature operation at a low 300 A / cm 2 threshold current density.