Fiber Optic Telecommunication

Introduction
               
                    Since its invention in the early 1970s, the use of and demand for optical fiber have grown
tremendously. The uses of optical fiber today are quite numerous. With the explosion of information traffic  due  to the Internet, electronic  commerce,  computer  networks,  multimedia, voice, data, and video,  the need for a  transmission medium with the  bandwidth  capabilities for handling  such vast amounts of  information is  paramount. Fiber optics, with  its comparatively  infinite bandwidth, has proven to be the solution.
                   Companies such as AT&T, MCI, and U.S. Sprint use optical fiber cable to carry plain old
telephone service (POTS) across their nationwide networks. Local telephone service providers use fiber to carry this same service between central office switches at more local levels, and sometimes as far as the neighborhood or individual home. Optical fiber is also used extensively for transmission of data signals. Large corporations, banks, universities, Wall Street firms, and others own private networks. These firms need secure, reliable systems to transfer computer and monetary information between buildings, to the desktop terminal or computer, and around the world. The security inherent in optical fiber systems is a major benefit. Cable television or community antenna television (CATV) companies also find fiber useful for video services. The high information-carrying capacity, or bandwidth, of fiber makes it the perfect choice for transmitting signals to subscribers.
                    The fibering of America began in the early 1980s. At that time, systems operated at 90 Mb/s. At this data rate, a single optical fiber could handle approximately 1300 simultaneous voice
channels. Today, systems commonly operate at 10 Gb/s and beyond. This translates to over 130,000 simultaneous voice channels. Over the past five years, new technologies such as dense wavelength-division multiplexing (DWDM) and erbium-doped fiber amplifiers (EDFA) have been used successfully to further increase data rates to beyond a terabit per second (>1000 Gb/s) over distances in excess of 100 km. This is equivalent to transmitting 13 million simultaneous phone calls through a single hair-size glass fiber. At this speed, one can transmit 100,000 books coast to coast in 1 second!
The growth of the fiber optics industry over the past five years has been explosive. Analysts expect that this industry will continue to grow at a tremendous rate well into the next decade and beyond. Anyone with a vested interest in telecommunication would be all the wiser to learn more about the tremendous advantages of fiber optic communication. With this in mind, we hope this module will provide the student with a rudimentary understanding of fiber optic communication systems, technology, and applications in today’s information world.