The purpose of this research is the development of semi-conductor coherent sources for lightwave applications. While the semi-conductor laser has achieved prevalence as a suitable source, new materials developments are occurring rapidly and are influencing such lasers. One such crystalline material is the so-called doping superlattice. This involves the generation of a periodic crystal lattice superimposed upon the underlying crystal lattice, the "superlattice" being obtained by preferential doping. This particular technique allows design of the coupling between the optical beam and the crystal as well as a certain degree of tunability of the frequency.