InGaAs strained quantum well lasers with emission wavelengths longer than GaAs lasers are of current interest because their threshold current densities Jth can be substantially lower than those of GaAs lasers of similar structure. The reduction in Jth is produced b the compressive strain in the InGaAs active layer, which reduces the effective density of states of the valence band. Experimentally, however, the reduction in Jth has not been as large as predicted. In addition, InGaAs lasers with emission wavelengths ~1 µm have had much lower differential quantum efficiencies ηd and characteristic temperatures To than GaAs devices.
© 1990 Optical Society of AmericaPDF Article