After installation in typical underground conduit plant, optical fiber cables will probably be exposed to temperatures of +30°F to +150°F. However, unless special precautions are taken during storage and shipment these cables may encounter temperatures as low as -40°F. Moreover, in metropolitan areas, steam exposed conduits can have temperatures exceeding +180°F. Dimensional changes within the optical fiber cable structure due both to linear thermal expansion of materials and polymeric shrinkback can result in variations in the optical transmission properties of the fiber, thus possibly impairing system performance. The dimensional changes resulting from thermal expansion (or contraction) are of a reversible nature while those resulting from polymeric shrinkback are of an irreversible nature. Furthermore, it will be shown that optical transmission properties of cabled fibers depend on thermal history and not temperature alone.
© 1977 Optical Society of AmericaPDF Article