Optic fiber attenuation

Loss of optical power of signal when it is transmitted through optic fiber is called as attenuation. Material dispersion, scattering, absorption, bending, splice loss, waveguide dispersion, intermodal dispersion etc. are the main attenuation mechanisms. In material dispersion, loss is due to the dispersion of white light. This can be avoided by using monochromatic light. Scattering of light signal may cause attenuation. Here Rayleigh scattering is significant. Actual reason for scattering is local variations in the refractive index in core part. Absorption of optical signal by the core material and impurities present in core material distorts the signal leading to attenuation. Both micro level and macro level bending of fiber leads to fiber loss or attenuation. Connectors, couplers and splicers in the fiber optic communication system diminish the signal and this loss is referred as splice loss. Waveguide dispersion which occurs in single mode fibers is the loss of signal due to refraction towards cladding. Intermodal dispersion which occurs in multimode fibers is the distortion of signal due to the different paths of signal.