PLANAR NATIVE-OXIDE INDEX-GUIDED ALXGA1-XAS-GAAS QUANTUM-WELL HETEROSTRUCTURE LASERS

A new form of planar index-guided laser diode is demonstrated with a relatively thick (approximately 0.4-mu-m) native oxide employed to define the lateral optical waveguide (transverse to the laser stripe). Oxidation of high-gap AlxGa1-xAs in a "wet" ambient results in the transformation of most of the upper confining layer to a lower-index current-blocking native oxide outside of the active stripe. Planar quantum well heterostructure (QWH) AlxGa1-xAs-GaAs laser diodes fabricated by this process exhibit both optical and current confinement. Continuous 300 K threshold currents as low as 10 mA (uncoated facets) and kink-free single-longitudinal-mode operation are demonstrated for approximately 2-mu-m-wide active region devices.