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10. Technologies that use optical fibers
Intro to this Guide
Light in a glass medium can carry more information over longer distances than electrical signals over a copper medium. It is also immune to electrostatic or electromagnetic interference. This guide provides an extensive overview of the construction, operation, and applications of optical fiber, with more emphasis on installation and troubleshooting.
The first step in the development of fiber for data communications applications was to develop a glass so pure that one per cent of the light would be retained at the end of a one kilometer length, the existing distance (without repeaters) for copper-based telephone systems. This represents an attenuation of 20 decibels per kilometer (20 dB/km). During the 1960s, researchers all over the world worked on the challenge and the breakthrough came in 1970 when Corning scientists Dr. Maurer, Dr. Keck and Dr. Schultz created a fiber with the required attenuation characteristics.
Since then, glass fiber technology has advanced tremendously in terms of performance and applications.
Current fiber performance is approaching the theoretical limits of silica-based glass materials and this enables fiber to transmit digitized light signals well beyond 100 km without amplification, when used in conjunction with appropriate electronics. When compared with the early attenuation levels of 20 dB per km, present achievable levels of less than 0.35 dB/km at 1310 nanometers (nm) and 0.25 dB/km at 1550 nm are quite remarkable.
Optic fiber is used extensively in the following applications, to name but a few:
• Machine vision
• Night vision
• Traffic control
• Data communications
• Local area networking
This guide gives both the novice and the experienced user a solid grasp of the principles and practical implementation of fiber optic cabling for industrial applications. After reading this guide, we believe you will have:
• A solid knowledge of fiber optic communications systems
• An understanding of state of the art fiber optics technology and installation practices
• The knowledge to attempt jointing, splicing and testing fiber optic systems
• Knowledge of the correct procedures for cable installation and termination
• The know-how to install your own fully operational fiber optics system
• Insight into new approaches on troubleshooting fiber optics
This guide is intended for engineers and technicians who are:
• Instrumentation and control engineers
• Electrical engineers
• Project engineers and managers
• Design engineers
• Telecommunications engineers and technicians
• Process control engineers
• Maintenance engineers, technicians and supervisors
• Consulting engineers
• Systems engineers
• Electrical and instrumentation technicians
A basic knowledge of electrical and electronic principles is useful in understanding the outlined concepts, but the guide also focuses on the fundamentals, hence understanding the key concepts should be easier.
The guide is laid out in a sequential manner to provide a logical study of the subject of fiber optics. It is also laid out in the order that would be used to design a fiber optic transmission system. The structure of the guide is as follows.
Section 1 --This section provides a background to the contents of the guide, an historical overview of the development of fiber optic communications and a comparison of copper and optical fiber technologies.
Section 2-- This section provides an introduction to the important fundamentals and concepts of electronic communications. This section also provides a brief review of the different types of copper cables and their operating parameters.
Section 3 -- This section discusses the theory associated with transmission of information down optical fibers. It covers the different types of fibers available, transmission parameters, the different modes of transmission and the losses associated with optical fibers.
Section 4--This section details the different type of cables that are available with optical fibers and how they are constructed. It provides details of the application and environment for using each type of cable construction.
Section 5--This section provides a detailed description of the different types of connections and joints that are used in fiber optic cables and the advantages and disadvantages of each. It also provides a thorough practical description of how to splice, joint and connect fiber optic cables.
Section 6-- This section discusses the theory and operation of optical devices, including drivers, detectors, couplers, grates and amplifiers. It provides details of the different types of optical devices that are available and their working parameters and limitations.
Section 7--This section describes the various methods used to install fiber optic cables. It provides a practical approach to installing cables in different environments and highlights all the potential problems that may be encountered.
Section 8-- This section provides a methodical and practical approach to designing a fiber optic communications system. It discusses in detail both loss budget and bandwidth budget analysis, and provides useful information on effective cost control when implementing fiber optic systems.
Section 9--This section describes the tests that can be carried out on optical fibers and explains how to carry out standard pre-installation and post installation testing on fiber optic systems. It also provides a brief description of how the parameters of a fiber are measured.
Section 10-- This section briefly discusses the main technologies and standards that use optical fibers as their transmission medium.