Separate‐confinement heterostructure diode lasers containing a strained Al0.18In0.20Ga0.62As single quantum well active layer and Al0.25Ga0.75As confining layers have been fabricated from structures grown on GaAs substrates by low‐pressure organometallic vapor phase epitaxy. The emission wavelength of these devices is 814 nm. Threshold current density is as low as 103 A cm−2for cavity lengthL=1500 &mgr;m, and differential quantum efficiency as high as 90% forL=280 &mgr;m. The characteristic temperatureT0is 214 K between 10 and 40 °C, and 159 K between 40 and 80 °C. Preliminary tests of cw operation suggest that these lasers are more reliable than AlGaAs/AlGaAs lasers.