Data are presented on curved‐resonator AlGaAs–GaAs quantum well heterostructure laser diodes employing a deep‐oxide guiding structure formed by a combination of impurity‐induced layer disordering and native oxidation. Room‐temperature, continuous wave (cw) threshold currents as low as ∼13 mA are measured for a ∼5 &mgr;m wide, 100 &mgr;m radius half‐ring laser employing a deep‐oxide structure. For similar 150 &mgr;m radius devices, cw threshold currents as low as ∼19 mA are observed (∼7 &mgr;m width), with total output powers exceeding 30 mW. Spectral data indicate single‐mode operation over a large current range (25–100 mA). The low‐threshold characteristics are attributed to the excellent current and optical confinement of the deep‐oxide structure, combined with low edge scattering loss. ©1995 American Institute of Physics.