ENHANCEMENTS IN MBE-GROWN HIGH-SPEED GAAS AND IN0.35GA0.65AS MQW LASER STRUCTURES USING BINARY SHORT-PERIOD SUPERLATTICES

The luminescence properties of molecular-beam epitaxially grown GaAs/AlGaAs multiple quantum-well laser structures with core and cladding layers consisting of either binary short-period superlattices (SPSLs) or ternary alloy layers are compared. Photoluminescence enhancements in the SPSL laser structures are attributed to improved gettering of background impurities. Low-temperature cathodoluminescence topography reveals regular 1-2 monolayer fluctuations in the QW widths of the ternary alloy laser structures, which are greatly reduced in the SPSL laser structures. The SPSL lasers demonstrate lower threshold currents than the ternary alloy devices. Modulation bandwidths of 16 and 21 GHz have been achieved for 3 X 200 mum2 SPSL lasers containing three GaAS or In0.35Ga0.65As QWs, respectively, in the active region.