thin barrier layer 10 which is of the first or second conductivity type and has lower doping than the transition layer 3 is first applied over the first highly doped denatured transition layer 3 this barrier layer 10 is formed for instance of n ingaalas the second highly doped denatured transition layer 2 for instance being formed of n ingaalas is applied over this lower doped barrier layer 10 and the second outer cover layer 1 for instance being formed of n ingaalas is applied over the second highly doped denatured transition layer 2 the material of the barrier layer 10 preferably has a greater band gap than the material of the spacer layer 4 in particular the barrier layer 10 forms a barrier for electrons that extend past the active zone and the spacer layer 4 the layer sequence that is formed of the spacer layer 4 the first highly doped denatured transition layer 3 the barrier layer 10 and the second highly doped denatured transition layer 2 acts as the second waveguide layer 14 in this case as in the case of the semiconductor body 13 of the exemplary embodiment of fig1 in this case again the semiconductor substrate 8 is provided with a first contact metallizing 11 and the second outer cover layer 1 is provided with a second contact metallizing 12 the exemplary embodiment of fig3 differs from the exemplary embodiment of fig1 in that an additional barrier layer 10 of the second conductivity type such.