Fiber Optic Reference Guide: A Practical Guide to Communications Technology, Third Edition
This guide is an ideal primer for newcomers to the fiber optics industry as well as a useful reference guide for seasoned fiber optics veterans.
TABLE OF CONTENTS Fiber Optic Reference Guide: A Practical Guide to Communications Technology, Third Edition
Chapter 4: Fiber Optic Cables
Chapter 3 discussed the methods for manufacturing optical fiber and detailed many of its important characteristics. Another important characteristic is that bare optical fiber is quite delicate, making their handling difficult, especially in multifiber situations. To make handling optical fiber easier, it is first "buffered" or coated with a thin primary coating by the fiber manufacturer. It is then most often cabled. Fiber optic cables also function to protect the optical fiber from mechanical damage such as bends, breaks, or cuts both during and after installation. The exact structure and properties of a fiber optic cable are often directly related to the application for which the cable is constructed as well as the environment in which the cable will be installed.
FIBER OPTIC CABLE CONSTRUCTION
Although cable construction is usually application-specific, there are elements common to all types of fiber optic cables. The first element is the fiber housing. The fiber housing is either a loose-tube or a tight-buffer construction. Figure 4.1 shows the differences in these two types of construction in both cutaway and cross-section form.
Figure 4.1: Fiber Optic Cable Construction
Loose-tube construction allows for lower attenuation but the tubes may permanently kink if the cable is bent beyond its limits, breaking the fiber. In loose-tube cable construction, the optical fibers are enclosed in plastic buffer tubes that are filled with a gel to impede water penetration. The buffer tubes are stranded around a dielectric or steel central member, which serves as an anti-buckling element. To save space,...
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