Fiber Optics can be defined as: the system or branch of engineering concerned with using optic fibers.  An optic fiber is a filament of glass that transmits  light and it most often referred to as simply “fiber”.

One fiber consists of a glass strand, only as wide as a human hair - about 10 microns across.  Each strand of fiber is covered with a shield of plastic to protect it and keep the light contained inside.  The word “optics” includes anything to do with sight.  You may have noticed that it is very hard to see without light so light behavior is a natural part of this topic as well.

The Corning Glass Works company produced the first optical fiber suitable for long-range communication in 1970. These fibers are bound together in cables and distributed in the network.

fiberHave you ever seen a decorative lamp that shines light through tiny strands?

That is exactly what fiber used in telecommunications networks looks like - with some modifications of course.  Fibers used in telecom are specially manufactured to keep the light going around corners and for long distances.  Believe it or not, some of your calls or computer traffic is transmitted on a laser or LED light pulsing through these tiny strands.

Fiber is a much more efficient method for transmitting signals than copper wires for several reasons:

1)  A strand of fiber optics is immune to electromagnetic interference.   This is major issue because the modern world is surrounded by electronic items that emit electromagnetic energy.  Electromagnetic  interference is caused by the energy that “leaks out” and affects other electronics around it.  This type  interference can even come from simple household appliances such as a toaster oven or microwave.

2) Another fabulous characteristic of fiber is that huge amounts of information can be transmitted on one tiny filament of glass.    In most cases, fiber does not go directly into homes and businesses, so special electronics are needed to convert the light pulses back into signals that can be transmitted through the “last mile” of copper wires.

Previously, the network was described in terms of copper wire cables.   While all of that is true, there are some of the paths have been either replaced or enhanced with fiber optic cables and equipment.

For example, most (if not all) of the trunk cables between central offices have been replaced with fiber optic systems to dramatically increase the speed of those transmissions.  AT&T Long Lines have been replaced for the same reason.

At present, the Network is a combination of these two types of systems; copper and fiber optics.   At some point in the near future, however,  the use of copper wired cables will be a thing of the past and all phone and computer transmissions will have fiber optic components.

Some companies have already begun offering fiber to the home; known as FTTP—Fiber To The Premise.  A fiber enters your home and is connected to a conversion box that connects to your TV, phone and computer.

At present, the only reason transmission of voice and computer signals are not at the speed of light is the mixture of copper and fiber in the network and the restrictions of the equipment that interprets these signals.

Telecom Networks 101: Part 1

Telecom Networks 101: Part 2

About the Author:

Saundra O’Neill began working for AT&T, and has spent the last fifteen years in utility design engineering for construction.  During this time her work in several fields of engineering (Civil, Structural and Telecom) established real world knowledge and experience in a wide variety of processes in the building industry with an emphasis on telecom Outside Plant and its processes.  Her experience and a desire to communicate/teach others, has expanded into technical writing - including software documentation and a variety of articles covering the telecommunications industry.  Visit Sandy’s simple telecommunications blog.