Tunable stimualted emission of radiation is achieved in AlxGa1−xAs/GaAs double heterostructures, in which the waveguiding GaAs region consists of a delta‐doped doping superlattice. The low‐temperature emission energy is 45 meV below the bulk band gap of GaAs for homogeneous optical excitation of the Fabry–Perot cavity. The emission energy is continuously tunable over 35 A˚ by inhomogeneous excitation of the cavity.