Optical and microwave performance of GaAs-AlGaAs and strained layer InGaAs-GaAs-AlGaAs graded index separate confinement heterostructure single quantum well lasers

GaAs-AlGaAs and strained layer In/sub 0.3/Ga/sub 0.7/As-GaAs-AlGaAs GRINSCH SQW lasers grown by molecular beam epitaxy are discussed. The strained-layers have threshold currents of 12 mA for 30- mu m*400- mu m devices (1000 A/cm/sup 2/) and threshold current densities of 167 A/cm/sup 2/ for 150- mu m*800- mu m devices. The threshold currents of strained-layer InGaAs lasers are lower than those of GaAs for all dimensions tested with 20- mu m-wide GaAs devices exhibiting threshold currents three times those of In/sub 0.3/Ga/sub 0.7/As devices. Microwave modulation of 10- mu m*500- mu m strained-layer lasers with simple mesa structures yields bandwidths of 6 GHz. For all dimensions tested, strained-layer InGaAs devices have greater bandwidths than GaAs devices. These measurements confirm theoretical predictions of the effects of valence band modification due to biaxially compressive strain.<>