CONTROL OF LIGHT-OUTPUT POLARIZATION FOR SURFACE-EMITTING-LASER TYPE DEVICE BY STRAINED ACTIVE LAYER GROWN ON MISORIENTED SUBSTRATE

We propose and demonstrate control of light-output polarization for su rface-emitting laser-type devices by using strained quantum-well activ e layers grown on a misoriented substrate. This structure has slightly asymmetric strain tenser elements on the surface plane. Due to orbita l-strain interaction, the valence band structures change and the optic al transition matrix element depends on the polarization of the light. Here, theoretical analysis and experimental results on the direction of misorientation are described, and it is shown that how the polariza tion of the light output is related to asymmetry in strain tensors. Fo r the devices, which have In0.2Ga0.8As active layers grown on a 2-degr ee-off-(100) GaAs substrate toward (111)B, the light-output is polariz ed in [0(1) over bar1$] with the reproducibility of as high as 88%. Th is highly controlled polarization is probably due to the combination o f converse piezoelectric effect and asymmetry in the lattice mismatch on the surface caused by misorientation.