Optimization and characteristics of Al-free strained-layer InGaAs/GaInAsP/GaInP SCH-QW lasers ( lambda approximately 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 demonstrated. In particular, optimization of the laser structure and growth conditions using gas-source molecular beam epitaxy have been studied. Closely optimized parameters have been found. The lasers exhibited very good device properties. The lowest threshold current densities obtained for a single-quantum-well laser and three-quantum-well laser were 72 and 150 A/cm/sup 2/, respectively. The internal quantum efficiency was 94%, and the internal waveguide loss was 5.4 cm/sup -1/. The transparency current density and gain coefficient were 33 A/cm/sup 2/ and 0.091- mu m/A, respectively. A characteristic temperature ranging from 220 to 280 K was obtained. A ridge waveguide 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 quantum-well lasers.<
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