A high‐performance index‐guided ten‐stripe AlxGa1−xAs‐GaAs quantum well heterostructure laser array fabricated using Si diffusion to effect impurity‐induced layer disordering between the active region stripes is described. The fine spacing (1 &mgr;m) between (3 &mgr;m) emitters allows coupled mode laser operation at thresholds (Ith) as low as 3–4 mA per stripe and with stable near‐ and far‐field patterns in spite of band filling (single quantum well). This form of coupled stripe laser is capable of high efficiency and high power output (250 mW at 300 mA) as well as a large excitation range extending fromIthto 9Ith.