Two AlGaAs/GaAs broadened waveguide laser structures, one asymmetric, one nearly symmetric, were designed for high power at about 780 nm. The design concept is based on low losses and higher gain for the fundamental mode with higher losses and lower gain for higher-order modes. To achieve these results, the positions of the quantum wells, thicknesses of the cladding layers, doping profiles, and the compositions of all the layers are carefully chosen. The structures are designed to have a loss of about 0.5/cm for the TE<sub>0</sub> mode and more than 5 /cm for higher order modes for both structures. The asymmetric structure has a lower threshold current density (~750 A/cm<sup>2</sup>) and a higher slope (about 0.9 W/A) of the light-current curve compared to the symmetric structure. Increased L-I slope for the asymmetric structure results mainly from increased hole injection efficiency because the quantum wells are close to the p-side. Ridge-guide lasers fabricated with the asymmetric structure produced greater than 350 mW at 25°C. The beam divergence of the asymmetric structure was 6° × 14°.
Spectral and output power data of distributed Bragg reflector lasers emitting in the technologically important wavelength
range from 780 nm to 1083 nm are presented. These devices are fabricated in a single molecular beam epitaxy growth
step, and the gratings are defined by holographic interferometry. Spectral dependencies on the grating and gain section
lengths are systematically investigated. Experimental data for the side-mode suppression ratio, mode spacing, and
thermal wavelength shift are given for devices emitting in the near infrared wavelength range between 780 nm and 1083