Dielectric Waveguide with a Core consisting of optically Transparent material of low attenuation (usually Silica glass) and with Cladding consisting of optically transparent material of lower Refractive Index than that of the core. It is used for the Transmission of signals with Lightwaves and is frequently referred to as a fiber. In addition, there are some optical components, such as Laser diodes, which are referred to as optical waveguides.