AlGaAs/GaAs diode lasers (1020–1100 nm) with an asymmetric broadened single transverse mode waveguide

Approaches to the development of laser heterostructures with a broadened single-mode waveguide are studied theoretically and experimentally. It is shown that the use of $n$- and $p$-type emitters with different refractive-index values ensures lasing in the fundamental mode only, if the thickness of the waveguide layer is 2 $\mu$m. The studied semiconductor lasers fabricated using the developed heterostructure feature internal optical losses amounting to 0.6 cm$^{-1}$; the divergence in the plane perpendicular to the $p$–$n$ junction is 23$^\circ$. In the continuous lasing mode at room temperature, a linear power-current characteristic is obtained at an output optical power as high as 7 W.