To reduce optical loss within fiber optic mechanical splices and connectors, apply optical couplant (matching gel) at the interface of the two mated fibers. matching approach a pragmatic alternative to zero-gap design. What Lucent, 3M, and other suppliers have discovered is To understand how an index-matching gel minimizes the that the secret to using index-matching gels is in the design of reflection light at the connection, consider the basic. Thorlabs offers reusable, mechanical fiber-to-fiber splices that are designed for splicing two single mode or multimode fibers. The TS126 Mechanical Fiber-to-Fiber Splice is compatible with fibers that have cladding sizes between Ø125 µm and Ø140 µm. They are easy to use, providing a quick solution. This AE Note discusses the use of index-matching gels in fiber optic components.