A relatively long strand of Transparent substance, usually glass, capable of conducting an
electromagnetic wave of optical Wavelength (visible or near visible region of the Frequency spectrum)
with some ability to confine longitudinally directed, or near longitudinally directed, Lightwaves to its
interior by means of internal reflection. The Fiber optic Waveguide may be homogeneous or radically
inhomogeneous with step or graded changes in its refractive index. The indices are lower at the outer
regions and the Core is thus of an increased refractive index.