The fundamental principles of basic semiconductor optical waveguide components are reviewed. Fabrication of these components require similar material and processing technologies as those used for advanced injection lasers. Compatibility of material and processing permits integration of optical and electronic components to form circuits of potentially high complexity. The monolithic integration of optical lasers and amplifiers with other waveguide components requires a high degree of control of composition and thick-ness of layer growth and advanced processing technologies which are reviewed briefly. Present material and process technologies make monolithic integration particularly attractive for controlling and improving the performance of, injection lasers, for permitting novel high speed modulation schemes, and for a number of switching applications. The integrated optic circuit design must allow for relatively large fabrication tolerances for the individual components without causing significant performance degradation or potential reliability problems. The feasibility of integration is demonstrated with a few examples such as optical switches, optical isolators and electrooptically tunable injection lasers.