Fiber Optic cabling is made with glass fibers. Provide very little variation in the signal they carry over long distances. Optical engineers have found that adding different additional chemicals to the basic silicon dioxide they can change the optical properties of the glass. By adding roughly 4% germanium dioxide (GeO2), for example, they can create a glass that has much less attenuation, and much 'flatter' attenuation across various frequencies of light, than silicon dioxide by itself. Although fibers can be made out of either plastic or glass, the fibers used in long-distance telecommunications applications are always glass, because of the lower optical absorption of glass. The light transmitted through the fiber is confined due to total internal reflection within the material.

FYI, fiber optic (the core of it, not shell to cover it) is made of glass and not plastic. The fiber optic strands of glass (optic fibers) within fiber optic cables carry analog or digital signals in the form of light waves. Distance and capabilities will increase even more once the glass becomes more pure.

Company Resource: Binoculars  Monocular Telescope  Waterproof Binoculars  
Read more: http://www.nbbinoculars.com/news/