OPTIMIZATION AND CHARACTERISTICS OF AL-FREE STRAINED-LAYER INGAAS GAINASP/GAINP SCH-QW LASERS (LAMBDA-SIMILAR-TO-980-NM) GROWN BY GAS-SOURCE MBE/

Aluminum-free strained-layer InGaAs/GaInAsP/GaInP separate confinement heterostructure quantum well lasers emitting at 980 nm have been demo nstrated. In particular, we have studied optimization of the laser str ucture and the growth conditions using gas-source molecular beam epita xy. Closely optimized parameters have been found. The lasers resulting from this work exhibited very good device properties. The lowest thre shold current densities obtained for the single-quantum-well laser and three-quantum-well laser were 72 and 150 A/cm2, respectively. The int ernal quantum efficiency was 94%, and the internal waveguide loss was 5.4 cm-1. The transparency current density and gain coefficient were 3 3 A/cm2 and 0.091 cm . mum . A-1, respectively. A high characteristic temperature ranging from 220 to 280 K was obtained. The ridge waveguid e laser exhibited a far-field pattern with a vertical divergence of 47 -degrees and a lateral divergence of 13-degrees. These characteristics compare favorably with the best values reported for InGaAs/AlGaAs qua ntum-well lasers.