The Use of Optical Couplers

Optical fiber couplers are used to connect two fiber optic connectors in order to ensure signal continuity. They are available in several models, the most common being LC and SC, and come in single-mode, multimode, simplex, or duplex versions.

Widely used in patch panels, these couplers guarantee precise alignment between fibers.

Single-mode fiber has a very thin core (around 9 µm): therefore, couplers must provide extremely high precision, with alignment accuracy on the order of a micron, in order to minimize optical loss. To achieve this, they are built with a ceramic sleeve that is precisely machined.

Multimode fiber, with a larger core (50 or 62.5 µm), is less demanding in terms of alignment tolerance. Multimode couplers are therefore sometimes manufactured with slightly lower precision.

It is possible to use a single-mode coupler with multimode fiber (although not optimal), but the opposite is not true: a multimode coupler does not provide the accuracy required for single-mode fiber.