High-power highly reliable Al-free 940-nm diode lasers

Al-free diode lasers emitting at 930 nm having a broadened step-index waveguide structure and a single active InGaAs quantum well have been realized by MOVPE. The impact of waveguide thickness on device performance has been studied. The highest wall plug efficiency of about 60% has been obtained with diode lasers having a 1-μm-thick waveguide. Increasing the waveguide thickness to 1.5 μm resulted in record low degradation rates below 10^-5 h^-1 for 3-W output power (100 μm stripe width). The same diode lasers showed a good long-term reliability even at an output power of 4 W. The best beam quality had diode lasers with a 2-μm-thick waveguide, at the expense of a reduced temperature stability