ABSTRACT
This chapter is devoted to the material attenuation sources and deals with attenuation sources depending on the waveguide properties. The absorption loss in high-silica glasses is composed mainly of ultraviolet and infrared (IR) absorption tails of pure silica, absorptions due to impurities, and IR absorption tails due to the presence of dopants inside the silica. The usual impurities that lead to spurious absorption effects in wavelength range of interest are transition metal ions and water in the form of OH ions. The general conclusion of the various studies conducted on the effect of hydrogen on fiber loss is that at ambient conditions, a properly designed and installed fiber cable should not show loss increase. The simplest qualitative description of the bending losses in a fiber can be obtained by assuming that in bent fiber, the field is not significantly changed compared to the field in the straight fiber.
