Abstract: This invention comprises a multi-mode optical "T"-splitter for the coupling of multi-mode optical fibers to, from, and between other fibers, sources, detectors, and other optical elements, and method of fabricating same. The optical T-splitters of this invention may use tubular waveguides to provide a better match with round fibers, resulting in higher efficiency, lower loss, and other improvements. The optical T-splitter is comprised of waveguides forming a substantially T-shaped geometry in a substrate. A reflecting element is inserted at the junction of the "T" to split input light entering one of the legs of the "T" into light being output between the other two legs of the "T". The "T" configuration of these tubular channels and the insertion of various types of reflecting elements at the "T" junction, make it possible to perform any number of optical functions, including splitting, tapping, mixing, and coupling.

Abstract: This invention comprises an optical circuit for the coupling of multi-mode optical fibers to, from and between other fibers, sources, detectors, and other optical elements, and method of fabricating same. The optical circuits of this invention can have round waveguides to provide a better match with round fibers, resulting in higher efficiency, lower loss, and other improvements. A substrate having a relatively low index of refraction is either machined or molded such that semi-circular grooves are formed in substrate surfaces. When two such substrates are aligned and adhered together, tubular channels in a substrate result. The design and placement of these tubular channels can be such that any number of optical functions can be performed, including splitting, tapping, mixing, and coupling. The optical circuits of this invention are relatively easy to manufacture and inexpensive, and exhibit low propagation and coupling loss.