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

Abstract

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 n_eff of the excitation mode over the substrate refractive index n_s (n_eff–n_s ≪ 1) is provided by selecting the thickness of Al_0.3Ga_0.7As confinement layers, which significantly increases the waveguide mode size and leads to directional-pattern narrowing.