Fiber optic loss calculation formula: Total link loss (LL) = Cable attenuation + Connector attenuation + Fusion attenuation [Note: If there are other components (such as attenuators), their attenuation values can be added]. Losses can be introduced by various means such as intrinsic material absorption, scattering, bending, connector loss and more. The OH+ absorption is predominant, and occurs most strongly around 1000 nm, 1400 nm and above1600 nm. Total attenuation is the sum of all losses. Optical losses of a fiber are usually expressed in decibels per kilometer (dB/km). So, how can we know the loss value on the fiber optic link? This article will teach you how to calculate the loss in the fiber. Optical fiber is a medium to carry information.