Figure 1. Basic structure of an optical fiber.
The cladding layer is made of a dielectric material with an
index of refraction. The index of refraction of the cladding
material is less than that of the core material. The cladding
is generally made of glass or plastic. The cladding
executes such functions as decreasing loss of light from
core into the surrounding air, decreasing scattering loss at
the surface of the core, protecting the fiber from absorbing
the surface contaminants and adding mechanical strength
[1].