SCATTERING CENTER

In the microstructure of a transmission medium , a site at which electromagnetic waves are scattered. Note 1: Examples of scattering centers are vacancy defects; interstitial defects; inclusions, such as a gas molecules, hydroxide ions, iron ions, and trapped water molecules; and microcracks or fractures in dielectric waveguides. Note 2: Scattering centers are frozen in the medium when it solidifies and may not necessarily cause Rayleigh scattering , which varies inversely as the fourth power of the wavelength . For example, in glass optical fibers, there is a high attenuation band at 0.95 m, primarily caused by scattering and absorption by OH (hydroxyl) ions. [ From Weik '89 ]