Losses in fiber optic cables are generally caused by three main problems: scattering, absorption, and bending losses. The scattering of light is a form of intrinsic attenuation. Optical Signal Attenuation is the single greatest factor limiting the distance and performance of your network. This guide will demystify signal loss, explore its causes, and show you how. Fiber loss, also called fiber optic attenuation or attenuation loss, refers to the loss of signal between input and output. It's measured in decibels per kilometer (dB/km), and it determines how far a signal can travel before it becomes too weak to read.