Far‐field emission patterns of GaAs&sngbnd;AlxGa1‐xAs double‐heterostructure lasers have been measured to determine the dependence of the beam divergence as a function of active layer thicknessdand compositionx. The beam divergence in the plane of the junction &thgr;∥is ∼ 10°, while the beam divergence perpendicular to the junction plane&thgr;⊥is considerably larger and depends strongly ondandx. Curves are given for&thgr;⊥and the confinement factor &Ggr; as a function ofdbetween 0.05 and 2.0 &mgr; forx= 0.1, 0.2, 0.3, and 0.4. These curves were calculated by considering the laser as a dielectric waveguide with a refractive index step between GaAs and AlxGa1−xAs.