Lasing characteristics of GaAs(311)A substrate based InGaAs-GaAs vertical-cavity surface-emitting lasers

An experimental investigation of lasing characteristics in InGaAs-GaAs vertical-cavity surface-emitting lasers (VCSELs) grown on GaAs(311)A substrates is presented. To improve temperature characteristics, the gain peak wavelength was detuned by -33 mm from the VCSEL cavity mode. It was found that anisotropic in-plane gain distribution in (311)A-oriented quantum wells (QWs) effectively controls polarization of VCSELs. A stable polarization mode was always exhibited along the [2¯33] direction, which corresponds to the crystallographic axis of maximum gain for (311)-oriented QWs, The [2¯33] polarization mode was maintained against injection currents of more than 2.5 times the threshold over the wide temperature range of 25°C to 150°C. The orthogonal [011¯] polarization mode was completely suppressed, and an suppression ratio of 19.8 dB between two orthogonal polarization modes was obtained at 1.8 times the threshold current at 80°C, the temperature at which the gain peak matches the cavity mode. In addition, a threshold current of 680 μA and a corresponding threshold current density of 55 A/(cm²·well) were achieved for a 25-μm square etched mesa device at 80°C