How to determine the magnitude of optical attenuation using an optical power meter
Optical attenuation compares input and output power on a logarithmic scale. When powers are in linear units, the loss in decibels is: Attenuation (dB) = 10 × log10 (Pin / Pout) If the link length L is provided, the attenuation coefficient is: Coefficient (dB/km) =. The operation of an optical fiber is based on the principle of total internal reflection. When the light crosses materials with different refractive indices the light beam will be partially refracted at the boundary surface, and partially reflected. The formula to calculate cable attenuation is: Cable Attenuation (dB) = Maximum Cable Attenuation Coefficient (dB/km) × Length (km) Connector loss occurs when optical power is lost as the signal passes through a connector.
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