A slender strand of transparent glass or plastic specially constructed to serve as a dielectric conductor, or waveguide, of infrared (IR) light in a fiber optic transmission system (FOTS).The fiber generally is one of many types of glass optical fiber (GOF) although plastic optical fiber (POF) is sometimes used. GOF offers the advantage of very low signal attenuation over long distances, in support of signaling rates that currently are as high as 40 Gbps per lambda, or wavelength. POF sometimes is used over short distances where its flexibility, general durability, and low cost are advantageous. See also GOF and POF.