An optical fiber is a transparent thin fiber for transmitting light.
The optical fiber can be used as a medium for telecommunication and networking because it is flexible and can be bundled as cables. The light transmitted through the fiber is confined due to total internal reflection within the material. This is an important property that minimizes signal crosstalk among fibers within the cable and allows the routing of the cable with twists and turns.
In some high-tech building, optical fibers are used to route sunlight from the roof to other parts of the building.