Intrinsic Optical Fiber Losses comprise of absorption loss, dispersion loss and scattering loss caused by the structural defects. Guidelines On What Loss To Expect When Testing Fiber Optic Cables To be able to judge whether a fiber optic cable plant is good, one does a insertion loss test with a light source and power meter and compares that to an estimate of what is a reasonable loss for that cable plant. The estimate. Factors causing fiber loss are various, such as intrinsic material absorption, bending, connector loss, etc. In turn, meeting this loss budget is critical in the functioning of the whole. Fiber optic loss, also known as optical attenuation, refers to the light loss between the transmitter and receiver. In summary, fiber optic loss is.