A review is given of recent progress in the development of integrated optical circuits involving the AlGa1-XAs/GaAs double heterostructure system. Various devices utilizing periodic corrugations or gratings are described briefly, whereas alternate attempts to fabricate optical circuits by wet chemical etching are discussed in more detail. The current trend to explore other III-V compounds is considered, with emphasis on the quaternary system GaxIn1-xPYAs1-y. Lattice matching of this quaternary to InP results in long wavelength emission, suitable for use with present optical fibers. A number of reasons are also given for increased investigation of this quaternary lattice-matched to GaAs.