Introduction to Optical Fiber Cable

An optical fiber cable is a cable containing one or more optical fibers that are used to carry light. The optical fiber elements are typically individually coated with plastic layers and contained in a protective tube suitable for the environment where the cable will be deployed. Optical fibers are widely used in fiber-optic communications, where they permit transmission over longer distances and at higher bandwidths (data rates) than wire cables. This article helps us know more of fiber cable from different aspects, such as design, reliability and quality, cable types and so on.

Design

In order to protect fiber from damage, there are different applications of optical fibers according to different environment. For indoor applications, the jacketed fiber is generally enclosed, with a bundle of flexible fibrous polymer strength members like aramid, in a lightweight plastic cover to form a simple cable. For use in more strenuous environments, a much more robust cable construction is required. In addition, a critical concern in outdoor cabling is to protect the fiber from contamination by water. Finally, the cable may be armored to protect it from environmental hazards, such as construction work or gnawing animals.

Modern cables come in a wide variety of sheathings and armor, designed for applications such as direct burial in trenches, dual use as power lines, installation in conduit, lashing to aerial telephone poles, submarine installation, and insertion in paved streets.

Reliability and Quality

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. There are three basic scenarios that can lead to strength degradation and failure by inducing flaw growth: dynamic fatigue, static fatigues, and zero-stress aging.

Cable Types

OFC: Optical fiber, conductive
OFN: Optical fiber, nonconductive
OFCG: Optical fiber, conductive, general use
OFNG: Optical fiber, nonconductive, general use
OFCP: Optical fiber, conductive, plenum
OFNP: Optical fiber, nonconductive, plenum
OFCR: Optical fiber, conductive, riser
OFNR: Optical fiber, nonconductive, riser
OPGW: Optical fiber composite overhead ground wire
ADSS: All-Dielectric Self-Supporting

Fiber Material

There are two main types of material used for optical fibers. These are glass and plastic. They offer widely different characteristics and therefore fibers made from the two different substances find uses in very different applications.

Color Coding

Individual fibers in a multi-fiber cable (as the picture below) are often distinguished from one another by color-coded jackets or buffers on each fiber. The identification scheme used by Corning Cable Systems is based on EIA/TIA-598, "Optical Fiber Cable Color Coding." EIA/TIA-598 defines identification schemes for fibers, buffered fibers, fiber units, and groups of fiber units within outside plant and premises optical fiber cables. This standard allows for fiber units to be identified by means of a printed legend. This method can be used for identification of fiber ribbons and fiber sub-units.

Capacity and Market

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". So they have a big market in fiber optic industry. For example, companies can lease or sell the unused fiber to other providers who are looking for service in or through an area.