Quantum well lasers based on strained InxGa1−xAs/InP were grown by atmospheric pressure metalorganic vapor phase epitaxy. Buried‐heterostructure lasers with the active layer consisting of three quantum wells, each ∼50 A˚ thick, placed in a continuously graded waveguide, exhibit threshold currents as low as 15 mA, high quantum efficiency (24%), and power output (∼100 mW), independent of composition. Changing the In concentration fromx=0.48 to 0.62 results in the lasing wavelength shift from 1.45 to 1.62 &mgr;m. These wavelengths are in excellent agreement with the calculated energies of the electron–heavy hole exciton transition.