- Loss of signal strength as it travels along a transmission path (medium) as
expressed in decibels.
- In a copper cable, attenuation increases with modulation frequency; the higher the frequency, the greater the loss.
In an optical fiber, attenuation is flat: loss is the same at any signalling frequency up to the highest useful ranges (begining around 1 GHz for Multimode graded index and around 10 GHZ for Single mode). The loss at very high frequency ranges is not a result from additional attenuation of the light itself by the optical fiber but is caused by loss of information rather than loss of optical power (signal). Information is contained within the variation of the optical power; as such, at very high frequencies, distortion causes a reduction or a loss of information
The Network Wiring Virtual Lecture by L. Scott Freudenthal