Editorial, Jan. 1975

This Special Issue of the IEEE TRANSACTIONS on Microwave Theory and Techniques is devoted to two closely related fields: integrated optics and optical waveguides. The subject of optical waveguides is pertinent to optical communications by means of glass fibers and to the circuitry of integrated optics. The theory of optical waveguides has reached a stage of relative maturity while integrated optics is still in a relatively early stage of its development. Fiber waveguides seem to have a fairly secure future since the spectacular successes of glass fiber research almost certainly ensure their application in optical communications systems. Already there are examples of experimental military applications of optical fibers and their use in the telephone system is anticipated.