tube. Figure 6-7 shows each type of fiber buffer. The choice of buffering techniques depends on the intended application. In large fiber count commercial applications, manufacturers use the loose-tube buffers. In commercial building and Navy applications, manufacturers use tight buffers.
Fiber-optic cables use strength members to increase the strength of the cable and protect the fiber from strain. Fiber-optic cables may use central support members in cable construction The central support members generally have buffered fibers or single fiber subcables stranded over their surface in a structured, helical manner. The central members may support the optical fibers as cable strength members or may only serve as fillers. Strength and support members must be light and flexible. The materials used for strength and support include steel wire and textile fibers (such as nylon and arimid yarn). They also include carbon fibers, glass fibers, and glass reinforced plastics.
The jacket, or sheath, material provides extra environmental and mechanical protection. Jacket materials may possess any number of the following properties:
Low smoke generation
Low halogen content
High abrasion resistance
Stable performance over temperature
It is difficult to produce a material compound that satisfies every requirement without being too costly. Jacket materials currently used include polyethylene, polyvinyl chloride, polyurethane, and polyester elastomers. Most commercial jacket materials are unsuitable for use in naval applications.
Figure 6-7. - Tight-buffered, loose-tube, and gel-filled loose-tube buffer techniques.Continue Reading