In this contribution, we investigated the design of an AlGaAs/AlGaInP electrically-pumped VECSEL structure emitting at a wavelength of 665 nm. With the finite element method (FEM) of an electro-thermal numerical model, we analyzed the current density distribution in the active region of different laser structures by changing the structure geometry, doping concentration of current spreading layer, and bottom contact size. A complete flip-chip processing is proposed according to the optimized designed structure. The measured results of the electroluminescence (EL) profile indicate that the diameter of the emission area with quasi-Gaussian distribution can be up to 100 μm, which is in good agreement with the numerical simulation.
In this report, we investigated the optical gain properties and lasing characteristics of a laser structure consisting of one single-layer of self-assembled InP quantum dots in Al<sub>0.10</sub>GaInP barriers. The optical gain and absorption spectra are obtained by analyzing the amplified spontaneous emission. An internal optical loss value of 5±2 cm<sup>−1</sup> , and a maximum peak modal gain of 39.3 cm<sup>−1</sup> for a single-sheet of QD were obtained at room temperature. The influence of temperature on the gain properties was studied. A 2.24-mm-long laser with uncoated facets emitting at 660 nm was demonstrated. A low threshold current density of 281 A/cm<sup>2</sup> with an external differential quantum efficiency of 34.2% was also achieved.