[en] We report results of characterization of injection microdisk lasers based on active layers employing 2, 5 and 10 layers of InGaAs quantum well-dot structures. The microlasers operate in continuous wave regime at room temperature without external cooling. The minimal microdisk diameter 10 µm is obtained for 5 layers of InGaAs quantum well-dot structures. Lasing wavelength is around 1.1…1.15 µm, minimal threshold current is 1.6 mA (threshold current density 900 A/cm²). (paper)

[en] Quantum-dot microdisk lasers coated with different dielectric layers transparent in spectral diapason of laser radiation were studied. We observe that the coating influences the mode spectra of the microlasers, reduces the resonator Q factor and improves their thermal resistance. (paper)

[en] A post-growth technique aimed at spatial modification of facet reflectance of edge-emitting diode lasers has been proposed. It is based on the deposition of an anti-reflection coating and subsequent precise etching with a focused ion beam. The technique allowed suppressing of high-order lateral modes in 10 μm stripe lasers based on ten layers of InAs/InGaAs quantum dots.

[en] The possible mechanisms of the polarization control in single-mode intracavity- contacted vertical-cavity surface-emitting lasers (IC-VCSELs) with the rhomboidal selectively- oxidized current aperture were investigated. It was found that the lasing emission polarization of all single-mode VCSELs is fixed along the minor diagonal of the rhomboidal-shape aperture (the [110] direction). Numerical modelling of carrier transport did not reveal any sufficient injection anisotropy in the laser active region, while the transverse optical confinement factors calculated for the fundamental mode with two orthogonal polarizations are identical. Optical loss anisotropy and/or gain anisotropy are the most likely mechanisms of inducing the polarization fixation. (paper)

[en] Optically pumped 3-6μm in diameters microdisk lasers with InGaAsN/GaAs quantum well active region has been studied. Single-mode CW lasing at 78K temperature in microdisk laser with 3 μm diameter is demonstrated. (paper)

[en] Optimum shape of the capacitance–voltage (C–V) characteristic is a critical parameter determining the efficiency of frequency multiplication in heterobarrier varactors (HBVs) operating in the millimeter and submillimeter frequency ranges. A numerical model for calculating the C–V characteristics and leakage currents of HBV heterostructures with arbitrary composition and doping profiles has been verified on the basis of published and original experimental data. A specially designed HBV heterostructure with three undoped InAlAs/AlAs/InAlAs barriers surrounded by nonuniformly doped n-InGaAs modulation layers has been grown by molecular beam epitaxy on InP substrate. Prototype HBVs manufactured using the proposed heterostructure demonstrated a nearly cosine shape of the C–V curve at bias voltages up to 2 V, increased overlap capacitance, and low leakage currents.

[en] Microdisk lasers 10–30 μm in diameter operating at room temperature without thermal stabilization and with an active region based on nanostructures of hybrid dimensionality—quantum wells–dots—are investigated. High-frequency measurements of the microlaser response are performed in the direct small-signal modulation mode, which makes it possible to establish the parameters of the operating speed and analyze their dependence on the microlaser diameter. It is found that the K factor is (0.8 ± 0.2) ns, which corresponds to optical losses of ~6 cm^–1, and no regular dependence on the diameter is observed. It is found that the low-frequency component of the damping coefficient of relaxation oscillations is inversely proportional to the diameter. This character of the dependence evidences a decrease in the carrier lifetime in small-diameter microcavities, which can be associated with the prevalence of nonradiative recombination on their side walls.

[en] The studies of the emission linewidth for single-mode near-IR vertical-cavity surface-emitting lasers with an active region based on InGaAs/AlGaAs quantum wells and different optical microcavity design. For low mirror loss, lasers with a 1λ cavity and carrier injection through distributed Bragg reflectors demonstrate a linewidth of 70 MHz and its growth to 110 MHz with increasing mirror loss (corresponding differential of efficiency ∼0.65 W/A). The design of the optical cavity with carrier injection through intracavity contacts and low-Q composition Bragg lattices reduces the linewidth to 40 MHz in spite of high mirror loss (corresponding differential efficiency of ∼0.6 W/A).

[en] We report a realization of room temperature lasing threshold of 1 μW in GaInP microdisk containing a few self-aggregated InP/GaInP quantum dots (QDs) grown by metal-organic vapor phase epitaxy. InP/GaInP QD microdisk cavities emitting in the spectral range of 700–800 nm and having the size of ~2 μm, free spectral range of ~35 nm and quality factors Q ~ 4000 were formed by wet chemical etching. Low dot density (~2 μm^–2) and large dot size (~150 nm), suggesting a single dot lasing and maximum overlap of QD and cavity mode, were achieved using deposition of 3 ML of InP layer at 700°C.

[en] Microdisk lasers based on three InGaAsN/GaAs quantum wells with different types of surface passivation are fabricated and studied under optical pumping. Room temperature lasing at 1.3 μm in 7 μm in diameter microdisks with InGaAsN/GaAs QW is demonstrated. We evaluated the thermal resistance as 1 °C/mW. (paper)