Light Attenuation: Notes
Attenuation refers to the reduction in strength of a signal. Light transmitted along the optical fiber becomes weaker the further it has to travel. Attenuation is usually measured in decibel units (dB). In fiber optic cables, attenuation is measured in terms of the number of decibels per unit of length (foot/meter etc). The less attenuation per unit distance, the more efficient the cable.
In comparison with an electrical circuit, think of attenuation as "light resistance". The more attenuation in the fiber optic cable, the less light output to the receiver module.
The average attenuation for fiber optic bus lines is .5 decibels (dB) for each connector and .3 dB for each meter of cable.