Wide-stripe, 0.97 &mgr;m emitting Al-free InGaAs(P)/InGaP/GaAs broad-waveguide separate confinement heterostructure quantum-well lasers demonstrate a record value for quasicontinuous wave (QCW) output power: 14.3 W (100-&mgr;m-wide stripe, 100 &mgr;s-wide pulses); and reach catastrophic optical mirror damage (COMD) in QCW operation at an optical power density of22.5 MW/cm2;that is, 40&percent; higher than COMD levels in cw operation. The devices have low internal losses(&agr;i=1 cm−1)and high external differential quantum efficiency (86&percent; for 2-mm-long lasers), and exhibit only 10–20 °C temperature rises in the active region at 10 W QCW power. We also show that long-cavity, large-contact-area devices exhibit relatively little spectral broadening with increased output power. ©1997 American Institute of Physics.