Impact of modal gain and waveguide design on two-state lasing in quantum well-dot lasers.

We study the current-controlled lasing switching from the ground state (GS) to the excited state (ES) transition in broad-area (stripe width 100 µm) InGaAs/GaAs quantum well-dot (QWD) and quantum well (QW) lasers. In the lasers with one QWD layer and a 0.45 µm-thick GaAs waveguide, pure GS lasing takes place up to an injection current as high as 8 A (40 kA/cm).

Temperature dependencies of the refractive index for Al-Ga-In-As metamorphic layers.

Temperature dependencies of the refractive indices, , for and metamorphic layers with =0.06-0.25 have been determined.

Highly efficient injection microdisk lasers based on quantum well-dots.

We study injection GaAs-based microdisk lasers capable of operating at room and elevated temperatures. A novel type of active region is used, namely InGaAs quantum well-dots representing a dense array of indium-rich islands formed inside an indium-depleted residual quantum well by metalorganic vapor phase epitaxy. We demonstrate a high output power of 18 mW, a differential efficiency of about 31%, and a peak electrical-to-optical power conversion efficiency of 15% in a 31 μm diameter microdisk laser.

Bragg reflectors for measuring optical parameters of layers of metamorphic InAlGaAs/GaAs heterostructures.

Spectroscopic reflectometry was used within 700-1600 nm wavelength range to investigate dispersion curves for InAlAs, InAlGaAs, and InGaAs layers, which constituted the purpose-made metamorphic InAlGaAs/GaAs Bragg reflector (BR). The procedure for determining the refractive index based on analyzing variations in cross-correlation coefficient obtained for reflection coefficient calculated and experimental dependences is presented. The sensitivity of the proposed method for variations in refractive index was investigated depending on the number of BR periods, the extinction coefficient of the layers of BR, and the wavelength range with respect to the main reflection maximum.

Hybrid InGaAs quantum well-dots nanostructures for light-emitting and photo-voltaic applications.

Hybrid quantum well-dots (QWD) nanostructures have been formed by deposition of 7-10 monolayers of In0.4Ga0.6As on a vicinal GaAs surface using metal-organic chemical vapor deposition.