7.3 POWER-RELATED IMPAIRMENTS MONITORING
7.3.1 Fiber Attenuation and Optical Power Loss
The most basic characteristic of a link is the power loss that is caused by fiber
attenuation and connections [17]. Attenuation, defined as the ratio of the input
power to the output power, is the loss of optical power as light travels along
the fiber. Attenuation in an optical fiber is caused by absorption, scattering,
and bending losses. The fundamental physical limits imposed on the fiber attenua-
tion are due to scattering off the silica atoms at shorter wavelengths and the
material absorption at longer wavelengths. There are two minima in the loss
curve, one near 1.3 mm and an even lower one near 1.55 mm. Fiber bending
can also induce power loss because radiation ...