Attenuation in an optical fiber occurs as a result of the way the light interacts with the structure of the fiber both at a microscopic and a macroscopic level. It is one of the parameters that can significantly be affected by the processes used to manufacture and install the cable.
All the intrinsic and extrinsic mechanisms that create this loss of signal are known to be wavelength dependent and as such are normally measured over the useable spectrum for which the fiber is designed,hence the term 'Spectral Attenuation' is used.
There are three main mechanisms to be considered:
It is possible to determine the effects of some of the mechanisms individually, and in this instance, the attenuation will be measured as a function of a predefined bending characteristic.
The 'Production/Lab/R&D' range is suitable for manufacturers of fiber and cables. It is considered unlikely that this measurement would be required in a field environment.