Fiber optic tutorial pdf

These cables are used mainly for digital audio connections between devices. The optical fiber elements are typically individually coated with plastic fiber optic tutorial pdf and contained in a protective tube suitable for the environment where the cable will be deployed.

Several layers of protective sheathing, depending on the application, are added to form the cable. Investigating a fault in a fiber cable junction box. The individual fiber cable strands within the junction box are visible. For use in more strenuous environments, a much more robust cable construction is required.

This protects the fiber from tension during laying and due to temperature changes. Loose-tube fiber may be “dry block” or gel-filled. Dry block offers less protection to the fibers than gel-filled, but costs considerably less. Instead of a loose tube, the fiber may be embedded in a heavy polymer jacket, commonly called “tight buffer” construction. 3┬ámm buffer tubing with an additional layer of Kevlar surrounding each fiber.

Distribution cables have an overall Kevlar wrapping, a ripcord, and a 900 micrometer buffer coating surrounding each fiber. A critical concern in outdoor cabling is to protect the fiber from contamination by water. This is accomplished by use of solid barriers such as copper tubes, and water-repellent jelly or water-absorbing powder surrounding the fiber. Finally, the cable may be armored to protect it from environmental hazards, such as construction work or gnawing animals. Modern fiber cables can contain up to a thousand fibers in a single cable, with potential bandwidth in the terabytes per second.

In some cases, only a small fraction of the fibers in a cable may be actually “lit”. Companies can lease or sell the unused fiber to other providers who are looking for service in or through an area. They may also deliberately under-invest to prevent their rivals from profiting from their investment. The highest strand-count singlemode fiber cable commonly manufactured is the 864-count, consisting of 36 ribbons each containing 24 strands of fiber. Optical fibers are very strong, but the strength is drastically reduced by unavoidable microscopic surface flaws inherent in the manufacturing process. The initial fiber strength, as well as its change with time, must be considered relative to the stress imposed on the fiber during handling, cabling, and installation for a given set of environmental conditions.