Fiber optic communication refers to a method of transmitting data that utilizes light instead of electrical signals to send information through optical fibers. Fiber is preferred. An optical fiber can be understood as a dielectric waveguide, which operates at optical frequencies. The device or a tube, if bent or if terminated to radiate energy, is called a waveguide, in general. Optical fiber s are made from either glass or plastic. Most are roughly the diameter of a human hair, and they may be many miles long.