Scattering loss:- Basically, scattering losses are caused by the interaction of light with density fluctuations within a fiber. Density changes are produced when optical fibers are manufactured.
Linear Scattering Losses: Linear scattering occurs when optical energy is transferred from the dominant mode of operation to adjacent modes. It is proportional to the input optical power injected into the dominant mode. Linear scattering is divided into two categories: Mie scattering and Rayleigh scattering.
Non- Linear Scattering Losses: Scattering loss in a fiber also occurs due to fiber non-linearity i.e. if the optical power at the output of the fiber does not changes proportionately with the power change at the input of the fiber, the optical fiber is said to be operating in the non-linear mode. Non-Linear scattering is divided into two categories: Stimulated Raman Scattering and Stimulated Brillouin Scattering.
Absorption loss:- Absorption loss in optical fiber is analogous to power dissipation in copper cables. Impurities in the fiber absorb light and convert it to heat. Absorption losses in optical fibers are due to three different mechanisms – i. Absorption by atomic defects in the glass composition. ii. Extrinsic absorption by impurities in the glass material. iii. Intrinsic absorption by the basic constituent atoms of the fiber material.