Fiber optic lights function no differently than fiber optic cables designed for communication, but the fibers used for lighting are often manufactured specifically for lighting applications, with larger cores and thinner claddings. The fibers themselves may be plastic or glass, though the intensity of the light source (illuminator) will have to be taken into consideration in the case of plastic, as it has a lower temperature tolerance than glass.

Fibers are bundled together and mounted at the output of the illuminator, which may be located away from the target illumination point of the light. This is useful in cases where an object should be illuminated, but not heated by the light source.