Fiber-Optic Communications

Summary

The field of fiber optics focuses on the transmission of signals made of light through fibers made of glass, plastic, or other transparent materials. The field includes the technology used to create optic fibers as well as modern applications such as telephone networks, computer networks, and cable television. Fiber optics are used in almost every part of daily life in technologies such as fax machines, cell phones, television, computers, and the internet.

Definition and Basic Principles

The field of fiber optics focuses on the transmission of signals made of light through fibers made of glass, plastic, or other transparent media. Using the principles of reflection, optical fibers transmit images, data, or voices and provide communications links for a variety of applications such as telephone networks, computer networks, and cable television.

Background and History

The modern field of fiber optics developed from a series of important scientific discoveries, principles, technologies, and applications. Early work in use of light as a signal by French engineer Claude Chappe, British physicist John Tyndall, Scottish physicist Alexander Graham Bell, and American engineer William Wheeler in the eighteenth and nineteenth centuries laid the foundation for harnessing light through conductible materials such as glass. These experiments also served as proof of the concept that sound could be transmitted as light. The failures in the inventions indicated further areas of work before use in practical applications: The main available light source was the sun, and the light signal was reduced by travel through the conductible substance. For example, in 1880 Bell created a light-based system of sound transmission, or photophone, that was abandoned for being too affected by the interruption of the light transmission beam. In the 1920s, the transmission of facsimiles (faxes) or television images through light signals via glass or plastic rods or pipes was patented by Scottish inventor John Logie Baird and American engineer Clarence Hansell. The fiberscope, developed in the 1950s, was able to transmit low-resolution images of metal welds over a glass fiber. In the mid-1950s, Dutch scientist Abraham Van Heel reported a method of gathering fibers into bundles and coating them in a clear coating or cladding that decreased interference between the fibers and reduced distortion effects from the outside. In 1966, English engineer George Hockham and Chinese physicist Charles Kao published a theoretical method designed to dramatically decrease the amount of light lost as it traveled through glass fibers. By 1970, scientists at Corning Glass Works created fibers that actualized Hockham and Kao's theoretical method. In the mid-1970s, the first telephone systems using fiber optics were piloted in Atlanta and Chicago. By 1984, other major cities on the Eastern seaboard were connected by AT&T's fiber-optic systems. In 1988, the first transatlantic fiber-optic cable connected the United States to England and France.

By the late 1980s, fiber-optic technology was in use for such medical applications as the gastroscope, which allowed doctors to look inside a patient and see the image transmitted along the fibers. However, more work was still needed to allow the effective and accurate transmission of electronic data for computer work.

In the mid-twentieth century, the use of fiber optics accelerated in number of applications and technological advances. Scientists found a way to create a glass fiber coated in such a way that the light transmitted moved forward at full strength and signal. Coupled with the development of the semiconductor laser, which could emit a high-powered, yet cool and energy-efficient, targeted stream of light, fiber optics quickly became integrated into existing and new technology associated with computer networking, cable television, telephone networks, and other industry applications that benefited from high-speed and long-distance data transfer.

How It Works

The major elements required for fiber-optics transmission include: long flexible fibers made of transparent materials such as glass, plastic, or plastic-clad silica; a light-transmittal source such as a laser of light-emitting diode (LED); cables or rods lined with a reflective core medium to direct light; and a receiver to capture the signal. Many systems also include a signal amplifier or optoelectronic repeater to increase the transmission distance of a signal. Electronic data is coded into light signals using the transmitter. The light signals then move down the fibers bouncing off the reflective core of the fibers to the receiver. The receiver captures the signals and then translates the light back into electronic data. This process is used to transmit data in the form of images, sound, or other signals down the rods at the speed of light.

Applications and Products

Information Transmittal. Fiber-optics technology revolutionized the ability to transfer data between computers. Networked computers share and distribute information via a main computer (a server) and its connected computers (nodes). The use of fiber optics exponentially increases the data-transmission speed and ability of computers to communicate. In addition, fiber-optics data transfer is more secure than lines affected by magnetic interference. Industries that use information and data transmission through networks include banking, communications, cable television, and telecommunications. Fiber-optic information transmission has advantages over copper-cable transmission in that it is relatively easy to install, is lighter weight, is very durable, can transmit for long distances at a higher bandwidth, and is not influenced by electromagnetic disruptions such as lightning or fluorescent lighting fixture transformers.

Modern Communications. The use of fiber-optics technology in telephone communication has increased the capacity, ease, and speed of standard copper-wired phones. The quality of voices over the phone is improved, as the sound signal is no longer distorted by distance or is subject to time delay. Fiber-optic lines are not affected by electromagnetic interference and are less subject to security breaches related to unauthorized access to phone calls and data transfer over phone lines. Additionally, fiber-optic cables are less expensive and easier to install than copper wire or coaxial cables, and since the 1980s they have been installed in many areas. Fiber-optic cabling can be used to provide high-speed internet access, cable television, and regular telephone service over one line. In addition to traditional phone lines and home-based services, fiber-optic links between mobile towers and networks also allow the use of smart phones, which can be used to send and receive e-mails, surf the internet, and have device-specific applications such as Global Positioning Systems (GPSs).

Manufacturing. The increased globalization of the manufacturing of goods requires information, images, and data to be transmitted quickly from one location to another (known as point-to-point connections). For example, a car may be assembled in Detroit, but one part may be made in Mexico, another in Taiwan, and a third in Alabama. The logistics to make sure all the parts are of appropriate quality and quantity to be shipped to Detroit for assembly are coordinated through networked computer systems and fiber-optic telephone lines. In addition, the ability to use fiber optics to capture and transmit images down a very small cable allows quality-control personnel to “see” inside areas that the human eye cannot. As an example, a fiberscope can be used to inspect a jet engine's welding work within combustion chambers and reactor vessels.

The Internet. According to the United Nations' International Telecommunication Union (ITU), the number of internet users across the world was nearly five billion in January 2022. Much like standard telephone service, the capacity, ease, and speed to the internet have been greatly increased by the replacement of phone-based modem systems, cable modems, and digital subscriber line (DSL) by fiber-optics wired systems. Although fiber-optic connections directly to homes in the United States are not available in all areas, some companies use fiber-optic systems down major networking lines and then split to traditional copper wiring for houses.

Medicine. Fiber optics have significantly altered medical practice by allowing physicians to see and work within the human body using natural or small surgical openings. The fiberscopes or endoscopes are fiber-optics-based instruments that can image and illuminate internal organs and tissues deep within the human body. A surgeon is able to visualize an area of concern without performing large-scale exploratory surgery. In addition to viewing internal body surfaces, laproscopic surgery using fiber-optic visualization allows the creation of very small cuts to target and perform surgery reducing overall surgical risks and recovery time in many cases. Beyond the use of endoscopes, fiber-optic technology has been used to update standard medical equipment so that it may be used in devices that emit electromagnetic fields. As an example, companies have developed a fiber-optic pulse oximeter to be used to measure heart rate and oxygen saturation during magnetic resonance imaging (MRI).

Broadcast Industry. The broadcast industry has moved much of its infrastructure to fiber-optics technology. This change has also allowed the creation and transmission of television signals with increased clarity and picture definition known as high-definition television (HDTV). The use of fiber optics and its increased data-transmission ability was key in 2009, when all television stations changed from analogue to digital signals for their content broadcasts.

Military. The military began using fiber optics as a reliable method of communications early in the development of the technology. This quick implementation was due to recognition that fiber optics cables were able to withstand demanding conditions and temperature extremes while still transferring information accurately and quickly. Programs such as the Air Force's Airborne Light Optical Fiber Technology (ALOFT) program helped move fiber-optic technology along even as it served as proof of concept: fiber-optic signal transmission could transmit data reliably even in outer space. Beyond communications, the military uses fiber-optic gyroscopes (FOGs) in navigation systems to direct guided missiles accurately. Additionally, fiber optics have been used to increase the accuracy of rifle-bullet targeting by using sensitive laser-based fiber-optic sensors that adjust crosshairs on the scope based on the precise measurement of the barrel's deflection.

Traffic Control. According to the United States Department of Transportation, traffic signals that are not synchronized result in nearly 10 percent of all traffic delays and waste nearly 300 million vehicle-hours nationwide each year. Fiber optics has been used as part of intelligent transport systems to help coordinate traffic signals and improve the flow of cars via real-time monitoring of congestion, accidents, and traffic flow. Beyond traffic congestion, some cities capture data on cars running red lights, paying tolls, and the license plates moving through toll roads, tunnels, and bridges.

Careers and Course Work

There are many careers in the fiber-optics industry and entry-level requirements vary significantly by position. Given the wide spectrum of difference between the careers, a sampling of careers and course work follows.

Professional, management, and sales occupations generally require a bachelor's degree. Technical occupations often require specific course work but not necessarily a bachelor's degree. However, it is easier to obtain employment and gain promotions with a degree, especially in larger, more competitive markets. Advanced schooling usually is required for supervisory positions—including technical occupations—which have greater responsibility and higher salaries. These positions comprise about 19 percent of the fiber-optics communications industry careers.

Engineering roles in the fiber-optics industry range from cable logistics and installation planning to research and development positions in fiber optics and lasers. Positions may be found in universities, corporations, and the military. Engineers may specialize in a particular area of fiber optics such as communication systems, telecommunications design, or computer network integration with fiber-optic technology. Education requirements for entry-level positions begin with a bachelor's degree in engineering, computer science, or a related field.

Telecommunications equipment installers and repairers usually acquire their skills through formal training at technical schools or college, where they major in electronics, communications technology, or computer science. Military experience in the field, on-the-job training with a software manufacturer, or prior work as a telecommunications line installer may also provide entry into more complicated or complex positions.

Optics physicists work in the fiber-optics industry in research and development. The role of the optics physicist is to develop solutions to fiber-optics communications quandaries using the laws of physics. Most optics physicists have a doctorate in physics, usually with a specialization in optics. They also tend to spend several years after obtaining their doctorate performing academic research before moving to industry positions.

Specialized roles in computer software engineering and networking in the fiber-optic telecommunications industry also exist. Much like the engineering roles, individuals may specialize in a particular area of fiber optics such as networking, communication systems, telecommunications design, data communications, or computer software. Education requirements for entry-level positions begin with a bachelor's degree with a major in engineering, computer science, or a related field.

Social Context and Future Prospects

Fiber-optic communications technologies are constantly changing and integrating new innovations and applications. Some countries, such as Japan, have fully embraced use of fiber optics in the home as well as in business; however, the investment in infrastructure is not as fully actualized in other areas. The consumer demand for faster, better access to the internet and related data-transmittal applications is driving the move from standard copper wiring to fiber optics. New types of fibers will increase fiber-optic application beyond telecommunications into more medical, military, and industrial uses. Though wireless technology use could negatively check industry growth, the strong consumer demand and increasing number of fiber-optics applications suggest that the fiber-optic industry will continue to grow. However, the industry may have more moderate growth as the telecommunication industry experiences decreased growth. This was seen during the economic recession of 2008 to 2010, as consumers held off upgrading from copper cabling to fiber optics. According to a report by Global Industry Analysts, the recession's impact on fiber-optic cabling ended in 2011. Overall, the report anticipates significant growth in the industry as more fiber-optic cable networks are installed and businesses, consumers, and telecom providers invest in advanced tools to facilitate the new networks. However, according to the US Bureau of Labor Statistics, employment for line installers and repairers, including installation and repair of fiber optic cables, was expected to change little or not at all from 2020 to 2030. The only openings anticipated were to fill in positions vacated by retirements.

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