Method for narrowing the directional pattern of an InGaAs/GaAs/AlGaAs multiwell heterolaser

A semiconductor laser with a new waveguide is developed. It allows significant narrowing of the directional pattern (to 4° in the plane perpendicular to the p–n junction). In the used waveguide, the minimum excess of the effective refractive index neff of the excitation mode over the substrate refractive index ns (neff–ns ≪ 1) is provided by selecting the thickness of Al0.3Ga0.7As confinement layers, which significantly increases the waveguide mode size and leads to directional-pattern narrowing.