Abstract

Recent progress in the field of fiber-optic communication creates an urgent demand for fiber directional couplers for applications to optic data bus networks, switches, modulators, power dividers/ combiners, and multiplexers/demultiplexers. T, star, and active couplers have been fabricated either in bundle configuration or in single-fiber fashion; however, none of these couplers offers bidirectional directivity. Integrated optics circuit (IOC) rectangular waveguide directional couplers have been investigated extensively by numerous authors; but their use may not be realistic in a practical communications system due to the interface losses between fibers and IOCs. This paper presents a 10-dB directional coupler, as depicted in Fig. 1, fabricated from Corning multimode low-loss individual fibers, with directivity better than 21.6 dB and insertion loss of 0.6-0.8 dB.

© 1976 Optical Society of America