Fiber optic cable

A fiber-optic cable, also known as an optical-fiber cable, is an assembly similar to an electrical cable

Optical fiber consists of a core and a cladding layer, selected for total internal reflection due to the difference in the refractive index between the two. In practical fibers, the cladding is usually coated with a layer of acrylate polymer or polyimide. This coating protects the fiber from damage but does not contribute to its optical waveguide properties. Individual coated fibers (or fibers formed into ribbons or bundles) then have a tough resin buffer layer or core tube(s) extruded around them to form the cable core. Several layers of protective sheathing, depending on the application, are added to form the cable. Rigid fiber assemblies sometimes put light-absorbing (“dark”) glass between the fibers, to prevent light that leaks out of one fiber from entering another. This reduces cross-talk between the fibers, or reduces flare in fiber bundle imaging applications

Jacket material

The jacket material is application-specific. The material determines the mechanical robustness, chemical and UV radiation resistance, and so on.

Fiber material

There are two main types of material used for optical fibers: glass and plastic. They offer widely different characteristics and find uses in very different applications.

Multi-fiber cables

Individual fibers in a multi-fiber cable are often distinguished from one another by color-coded jackets or buffers on each fiber.


Signal loss in optic fiber is measured in decibels (dB). A loss of 3 dB across a link means the light at the far end