Data are presented on a high‐performance native‐oxide coupled‐stripe AlyGa1−yAs‐GaAs‐InxGa1−xAs quantum well heterostructure laser realized by the recently introduced simple process of ‘‘wet’’ oxidation (H2O vapor+N2,≳400 °C, 3 h) of the upper AlyGa1−yAs confining layer. If the native oxide between active stripes (ten 5 &mgr;m stripes on 10 &mgr;m centers) is brought into closer proximity with the waveguide and quantum well region (i.e., from 0.53 to 0.4 &mgr;m), the 10‐stripe laser operates decoupled because of increased (coupling) absorption losses and some index guiding.