Early Applications for Fiber Optics

The United States armed services immediately took advantage of Fiber optics to improve their communications and tactical systems. In the early 1970s, the U. S. navy installed a fiber optic telephone system aboard the USS Little Rock. In 1976, the air force followed suit by developing its Airborne Light Optical Fiber Technology, ALOFT, program. The early successes of these applications spawned a number of military research and development programs to create stronger fibers, tactical cables, ruggedized, high performance components for applications ranging from aircraft to undersea.

Soon after, commercial applications began to appear. The broadcast television industry was always interested in systems that offered superior video transmission quality.  They embraced fiber optics video transmission.  The Broadcast Networks televising the Olympics every year utilized the newest technology currently available. In 1980, broadcasters of the winter Olympics, in lake placid, New York, requested a fiber optics video transmission system for backup video feeds. The fiber optic feed, because of its quality and reliability, soon became the primary video feed, making the 1980 winter Olympics the first use of fiber optics for a live television production in history.

The telecommunications industries took advantage of this new technology. In 1977, both AT&T and GTE created fiber optic telephone systems in Chicago and Boston, respectively. Soon after, fiber optic telephone networks increased in number and in reach. Network designers originally specified Multimode grated index fiber, but by the early 1980s, Singlemode fiber operating in the 1310nm and later in the 1550nm wavelength windows became the standard.  In 1983, British Telecom’s entire phone system used Singlemode fiber exclusively.  Computer and information networks slowly moved to fiber.  Today fiber is favored over copper due to lighter weight cables, lightning strike immunity and the increased bandwidth over longer distances.

In the mid 1980s, the United States government deregulated telephone service, allowing small telephone companies to compete with the giant,  AT&T.  Company’s like MCI and Sprint led the pace by installing regional fiber optic telecommunications networks throughout the world. Existing natural rights of way, such as railroad lines and gas pipes allowed these companies to install thousands of miles of fiber optic cable.   With this boom, the fiber transmission capacity struggles to keep up with the demand.  The optical fiber needed to increase in bandwidth over greater distances.
In 1990, Bell Labs sent a 2.5 Gigabit per second signal over 7500 KM without regeneration. With the use of soliton lasers and erbium-doped fiber amplifier or EDFA, the light pulses maintained their shape and intensity.   In the 1998, Bell Labs success went one better as researchers transmitted 100 simultaneous optical signals.  Each optical signal was at a data rate of 10 Gigabit per second and was transported for a distance of nearly 250 miles.  The bandwidth on one fiber was increased to 1 Terabit per second.  This was achieved using dense wavelength division multiplexing or DWDM technology which allows multiple wavelengths to be combined into one optical signal. Figure 10 illustrates a basic DWDM system.

Dense Wave Division Multiplexing, Figure 10.

DWDM technologies continue to develop as the thirst for bandwidth increases. The potential bandwidth of fiber is 50 Terra-Hertz or better.  DWDM technology has decreased greatly in cost and power consumption over the years.  The DWDM laser technology requires strict temperature control and compensation.  This makes the device draw high amounts of power and adds to the system costs.  Today it is still a rather expensive form of optical multiplexing.  More commonly used in the broadcast television industry is coarse wave division multiplexing or CWDM.  CWDM technology gives the ability for up to 18 simultaneous optical signals on one fiber.  This gives a usable bandwidth of more than 70 gigabits per second.  CWDM optics are relatively common that operate at 4 Gbps.

The FCC mandated that all broadcasters switch from analog to digital or high definition television standards.  This presented researchers with the challenge to provide high bandwidth fiber optic transport for high definition television.

Beyond broadcast television, however, consumers are pushing to have broadband services, including data, audio, video delivered to the home. Broadband services allowed interactive communications for both consumers and businesses, bringing to reality interactive video networks, interactive banking, shopping from the home, interactive distance learning just to name a few applications. Video on Demand hit a brick wall in coaxial cable television systems that excelled at carrying the same Video signal to everyone, but failed as a means to route switch signals. That will not be true for the next generation of fiber optics technology. Video transmission and fiber optic technology are naturally suited to one another.

Early Applications for a Fiber Optics, Introduction to Fiber Optics Applications, broadcast, fiber, optics, television, video