Short wavelength Alx’Ga1−x’As‐AlxGa1−xAs (x’∼0.85,x∼0.22) quantum‐well heterostructure (QWH) laser diodes (well sizeLz≊400 A˚) that operate continuously (cw) at 300 K are subjected to hydrostatic pressure (≲12 kbar). The emission spectrum and the light intensity versus current (L‐I) curves are monitored to determine the pressure dependence of the direct (&Ggr;) band gap and the threshold current. The band gap exhibits a linear pressure dependence with a noticeable change in slope at ∼4.5 kbar, similar to previously reported results for AlxGa1−xAs‐GaAs QWH diodes. The threshold current increases monotonically with pressure, reflecting the increasing loss of carriers to theXandLbands. The short‐wavelength cw limit of the system, i.e., a gain‐guided laser with a 400‐A˚ AlxGa1−xAs (x∼0.22) quantum well and no separate waveguide region, is determined to be ∼6980 A˚.