Advantages And Disadvantages Of Fiber Optics

This paper looks at fiber optics as a technology that has been developing and improving the way the world communicates for more than two centuries. It examines its origins from 1790, when a French engineer Claude Chappe invented a system for sending messages using a series of semaphores mounted on top of two towers.

This paper examines the advantages and disadvantages of fiber optics and describes some of the uses of fiber optics in our everyday lives.

It analyzes the manner in which fiber optic technology has revolutionised and advanced the field of telecommunications, imaging and data transmission. Modern information systems handle ever-increasing data loads, processor speeds and high-speed interconnection networks, thus impacting our world and expanding the boundaries of our technological development in all spheres of life.

INTRODUCTION

Nothing in the world gives us more power and confidence than having information. The ability to communicate information is essential to achieve the successful advancement of humankind. Transmission of information is imperative to the expansion of our horizons.

What does this all have to do with fiber optics? This research paper will cover the basis of fiber optics in terms of its transmission, communication, origin, uses and applications.

Fiber optics transports light in a very directional way. Light is focused into and guided through a cylindrical glass fiber. Inside the core of the fiber, light bounces back and forth at angles to the side walls, making its way to the end of the fiber where it eventually escapes. The light does not escape through the side walls because of total internal reflection.

Why is fiber optics so important? Besides being a flexible conduit that is used to illuminate microscopic objects, fiber optics can also transmit information similarly to the way a copper wire can transmit electricity. However, copper transmits only a few million electrical pulses per second, compared to an optical fiber that carries up to a 20 billion light pulses per second. This means telephone, cable and computer companies can handle huge amounts of data transfers at once, much more than conventional wires can carry. Fiber optic cable was developed because of the incredible increase in the quantity of data over the past 20 years. Without fiber optic cable, the modern Internet and World Wide Web would not be possible.

Origin of Fiber Optics

Even though it may seem new, the origin of fiber optics actually that dates back several centuries.

This is a brief timeline illustrating the history and discovery of fiber optics.

1790

French engineer Claude Chappe invented the first “optical telegraph.” This was an optical communication system which consisted of a series of human operated semaphoresmounted on top of a tower.

1870

Irish philosopher and physicist, John Tyndall, demonstrated to the Royal Society, that light used internal reflection to follow a specific path. This simple experiment marked the first research into the guided transmission of light.

1880

Alexander Graham Bell patented an optical telephone system called the “photo phone.” The “photo phone” was an optical voice transmission system that used light to carry a human voice. This unique device used no wires to connect the transmitter and the receiver.

William Wheeler invented a system of light pipes lined with a highly reflective coating that lit up homes. He used a light from an electric arc lamp placed it in the basement and directed the light around the home with the pipes.

1888

Dr. Roth and Prof. Reuss of a medical company in Vienna used bent glass rods to illuminate body cavities.

1895

The French engineer Henry Saint-Rene designed a system of bent glass rods.

1898

David Smith, an American from Indianapolis, applied for a patent on a dental illuminator using a curved glass rod.

1926

John Logie Baird applies for British patent on an array of parallel glass rods or hollow tubes to carry image in a mechanical television. Baird’s 30 line images were the first demonstrations of television using the total internal reflection of light.

During the same year, Clarence W. Hansell outlined principles of the fiber optic imaging bundle

1930

Heinrich Lamm, a German medical student, was the first person to assemble a bundle of transparent fibers together to carry an image. During these experiments, he transmitted an image of a light bulb filament through the bundle of optical fibers. His attempt to file a patent is denied because of Hansell’s British patent.

1931

Owens-Illinois invented a method to mass-produce glass fibers for Fiberglas.

1937

Armand Lamesch of Germany applied for U.S. patent on two-layer glass fiber.

1939

Curvlite Sales offered illuminated tongue depressor and dental illuminators made of Lucite, a transparent plastic invented by DuPont.

1951

Holger Moeller applied for a Danish patent on fiber optic imaging in which he used cladding on glass or plastic fibers with transparent low-index material. This patent was also declined because of Hansell’s patents.

In October of that same year, Brian O’Brien, from the University of Rochester suggested to Abraham C. S. Van Heel of the Technical University of Delft, that applying a transparent cladding would improve transmission of fibers in his imaging bundle.

1954

The Dutch scientist Abraham Van Heel and British scientist Harold H. Hopkins separately published papers on imaging bundles. Hopkins delivered his paper on imaging bundles of unclad fibers while Van Heel reported on simple bundles of cladded fibers that greatly reduced signal interference.

American Optical hired Will Hicks to implement and develop fiber optic image scramblers, an idea O’Brien proposed to the Central Intelligence Agency (CIA).

1955

Hirschowitz and C. Wilbur Peters hired an undergraduate student, Larry Curtiss, to work on their fiber optic endoscope project.

1956

Curtiss suggested making glass clad fibers by melting a tube onto a rod of higher-index glass.

Later that year Curtiss made the first glass-clad fibers using the rod-in-tube method.

1957

Hirschowitz was the first to test fiber optic endoscope in a patient.

The Image scrambler project ended after Hicks tells the CIA the code was easy to break.

1959

Working with Hicks, American Optical drew fibers so fine they transmitted only a single mode of light.

Elias Snitzer recognised the fibers as single-mode waveguides.

1960

Theodore Maiman demonstrated the first laser at Hughes Research Laboratories in Malibu.

1961

Elias Snitzer of American Optical published a theoretical description of single mode fibers. A fiber with a core so small it could carry light with only one wave-guide mode.

1964

Charles Kao and George Hockham, of Standard Communications Laboratories in England, published a paper indicating that light loss in existing glass fibers could be decreased dramatically by removing impurities.

1967

Corning summer intern, Cliff Fonstad, made fibers. Loss is high, but Maurer decides to continue the research using titania-doped cores and pure-silica cladding.

1970

Corning Glass researchers Robert Maurer, Donald Keck and Peter Schultzinvented fiber optic wire or “Optical Waveguide Fibers” capable of carrying 65,000 times more information than copper wire. These optical fibers could carry information in a pattern of light waves and could be decoded at a destination a thousand miles away.

The Corning breakthrough was among the most dramatic of many developments that opened the door to fiber optic communications. In that same year, Morton Panish and Izuo Hayashi of Bell Laboratories worked with a group from the Ioffe Physical Institute in Leningrad (now St. Petersburg) and made the first semiconductor diode laser capable of emitting continuous waves at room temperature.

Telephone companies began to incorporate the use of optical fibers into their communications infrastructure.

1973

Bell Laboratories developed a modified chemical vapour deposition process that heats chemical vapours and oxygen to form ultra-transparent glass that can be mass-produced into low-loss optical fiber. This process still remains the standard for fiber-optic cable manufacturing

1975

First non-experimental fiber-optic link installed by the Dorset police in UK police after lightning knocks out their communication system

1977

Corning joined forces Siemens Corporation, to form Corning Cable Systems. Corning’s extensive work with fiber, coupled with Siemens’ cabling technology, helped launch a new era in the manufacturing of optical fiber cable.

General Telephone and Electronics started to send live telephone messages through underground fiber optic cables at 6Mbit/s, in Long Beach, California.

Bell System started to send live telephone messages through fibers in underground ducts at 45Mbit/s, in downtown Chicargo.

1978

Optical fibers began to carry signals to homes in Japan

AT &T, British Post Office and STL pledge to develop a single mode transatlantic fiber cable to be operational by 1988.

1980

Graded-index fiber system carries video signals for the 1980 Winter Olympics in Lake Placid, New York.

1981

British Telecom transmits 140 million bits per second through 49 kilometers of single-mode fiber at 1.3 micrometers

1982

MCI leases the right of way to install single-mode fiber from New York to Washington. The system will operate at 400 million bits per second at 1.3 micrometers.

1984

British Telecom lays the first submarine fiber to carry regular traffic to the Isle of Wight.

1985

Single-mode fiber spreads across America, carrying long distance telephone signals at 400 million bits per second.

1986

The first fiber optic cable begins service across the English Channel.

In the same year, AT&T sends 1.7 billion bits per second through single-mode optic fiber

1991

Masataka Nakazawa of NTT reports sending soliton signals through a million kilometres of cable

1996

Fujitsu, NTT Labs and Bell Laboratories all report sending one trillion bits per seconds through a single optical fiber. They have all used separate experiments and different techniques to achieve this.

APPLICATIONS OF FIBER OPTICS

As the popularity of optical fibers continue to grow, so does their applications and practical uses. Fiber optic cables became more and more popular in a variety of industries and applications.

Communications / Data Storage

Since fiber optics are resistant to electronic noise, fiber optics has made significant advances in the field of communications. The use of light as its source of data transmission has improved the sound quality in voice communications. It is also being used for transmitting and receiving purposes.

Military

Optical systems offer more security than traditional metal-based systems. The magnetic interference allows the leak of information in the coaxial cables. Fiber optics is not sensitive to electrical interference; therefore fiber optics is suitable for military applications and communications, where signal quality and security of data transmission are important.

The increased interest of the military in this technology caused the development of stronger fibers, specially designed cables and high quality components. It was also applied in more varied areas such as hydrophones for seismic and sonar, aircrafts, submarines and other underwater applications.

Medical

Fiber optics is used as light guides, imaging tools and as lasers for surgeries. Another popular use of fiber optic cable is in an endoscope, which is a diagnostic instrument that enables users to see through small holes in the body. Medical endoscopes are used for minimum invasive surgical procedures. Fiber optics is also used in bronchoscopes (for lungs) and laparoscopes.

All versions of endoscopes look like a long thin tube, with a lens or camera at one end through which light is emitted from the bundle of optical fibers banded together inside the enclosure.

Mechanical or Industrial

Industrial endoscopes also called a borescope or fiberscope, enables the user to observe areas that are difficult to reach or to see under normal circumstances, such as jet engine interiors, inspecting mechanical welds in pipes and engines, inspecting space shuttles and rockets and the inspection of sewer lines and pipes.

Networking

Fiber optics is used to connect servers and users in a variety of network settings. It increases the speed, quality and accuracy of data transmission. Computer and Internet technology has improved due to the enhanced transmission of digital signals through optical fibers.

Industrial/Commercial

Fiber optics is used for imaging in areas which are difficult to reach. It is also used in wiring where electromagnetic interference (EMI) is a problem. It gets used often as sensory devices to make temperature, pressure and other measurements as well as in the wiring of motorcars and in industrial settings.

Spectroscopy

Optical fiber bundles are used to transmit light from a spectrometer to a substance which cannot be placed inside the spectrometer itself, in order to analyse its composition. A spectrometer analyses substances by bouncing light off of and through them. By using optical fibers, a spectrometer can be used to study objects that are too large to fit inside, or gasses, or reactions which occur in pressure vessels.

Broadcast/CATV /Cable Television

Broadcast or cable companies use fiber optic cables for wiring CATV, HDTV, internet, video and other applications.

Usage of fiber optic cables in the cable-television industry began in 1976 and quickly spread because of the superiority of fiber optic cable over traditional coaxial cable. Fiber optic systems became less expensive and capable of transmitting clearer signals further away from the source signal. It also reduced signal losses and decreased the number of amplifiers required for each customer. Fiber optic cable allows cable providers to offer better service, because only one optical line is needed for every ± 500 households.

Lighting and Imaging

Fiber optic cables are used for lighting and imaging and as sensors to measure and monitor a vast range of variables. It is also used in research, development and testing in the medical, technological and industrial fields.

Fiber optics are used as light guides in medical and other applications where bright light needs to shine on a target without a clear “line-of-sight path”. In some buildings, optical fibers are used to route sunlight from the roof to other parts of the building. Optical fiber illumination is also used for decorative applications, including signs, art and artificial Christmas trees.

Optical fiber is an essential part of the light-transmitting concrete building product, LiTraCon which is a translucent concrete building material.

ADVANTAGES OF FIBER OPTICS

The use of fiber optics is fast becoming the medium of choice for telecommunication systems, television transmission and data networks. Fiber optic cables have a multitude of advantages and benefits over the more traditional methods of information systems, such as copper or coaxial cables.

Speed

One of the greatest benefits to using fiber optic systems is the capacity and speed of such a system. Light travels faster than electrical impulses which allow faster delivery and reception of information. Fiber optic cables also have a much higher capacity for bandwidth than the more traditional copper cables.

Immunity to electromagnetic interference

Coaxial cables have a tendency for electromagnetic interference, which renders them less effective. Fiber optics is not affected by external electrical signals, because the data is transmitted with light.

Security

Optical systems are more secure than traditional mediums. Electromagnetic interference causes coaxial cables to leak information. Optical fiber makes it impossible to remotely detect the signal which is transmitted within the cable. The only way to do so is by actually accessing the optical fiber itself. Accessing the fiber requires intervention that is easily detectable by security surveillance. These circumstances make fiber optics extremely attractive to governments, banks and companies requiring increased security of data.

Fire prevention

Copper wire transmission can generate sparks, causing shortages and even fire. Because fiber optical strands use light instead of electricity to carry signals, the chance of an electrical fire is eliminated. This makes fiber optics an exceptionally safe form of wiring and one of the safest forms of data transmission.

Data signalling

Fiber optic systems are much more effective than coaxial or copper systems, because there is minimal loss of data. This can be credited to the design of optical fibers, because of the principle of total internal reflection. The cladding increases the effectiveness of data transmission significantly. There is no crosstalk between cables, e.g. telephone signals from overseas using a signal bounced off a communications satellite, will result in an echo being heard. With undersea fiber optic cables, you have a direct connection with no echoes.

Unlike electrical signals in copper wires the light signals from one fiber do not interfere with those of other fibers in the same cable. This means clearer phone conversations or TV reception.

Less expensive

Several kilometers of optical cable can be made far cheaper than equivalent lengths of copper wire. Service, such as the internet is often cheaper because fiber optic signals stay strong longer, requiring less power over time to transmit signals than copper-wire systems, which need high-voltage transmitters.

Large Bandwidth, Light Weight and Small Diameter

Modern applications require increased amounts of bandwidth or data capacity, fiber optics can carry much larger bandwidth through a much smaller cable and they aren’t prone to the loss of information. With the rapid increase of bandwidth demand, fiber optics will continue to play a vital role in the long-term success of telecommunications.

Space constraints of many end-users are easily overcome because new cabling can be installed within existing duct systems. The relatively small diameter and light weight of optical cables makes such installations easy and practical.

Easy Installation and Upgrades

Long lengths of optical cable make installation much easier and less expensive. Fiber optic cables can be installed with the same equipment that is used to install copper and coaxial cables.

Long Distance Signal Transmission

The low attenuation and superior signal capacity found in optical systems allow much longer intervals of signal transmission than metallic-based systems. Metal based systems require signal repeaters to perform satisfactory. Fiber optic cables can transmit over hundreds of kilometres without any problems. Even greater distances are being investigated for the future.

To use fiber optics in data systems have proven to be a far better alternative to copper wire and coaxial cables. As new technologies are developed, transmission will become even more efficient, assuring the expansion of telecommunication, television and data network industries.

DISADVANTAGES OF FIBER OPTICS

Despite the many advantages of fiber optic systems, there are some disadvantages.

The relative new technology of fiber optic makes the components expensive. Fiber optic transmitters and receivers are still somewhat expensive compared to electrical components. The absence of standardisation in the industry has also limited the acceptance of fiber optics. Many industries are more comfortable with the use of electrical systems and are reluctant to switch to fiber optics.

The cost to install fiber optic systems is falling because of an increase in the use of fiber optic technology. As more information about fiber optics is made available to educate managers and technicians, the use of fiber optics in the industry will increase over time.

The advantages and the need for more capacity and information will also increase the use of fiber optics in our everyday life.

Conclusion

From its humble beginnings in the 1790’s to the introduction of highly transparent fiber optic cable in the 1970’s, very high-frequency optic fibers now carry phenomenal loads of communication and data signals across the country and around the world.

From surgical procedures to worldwide communication via the internet, fiber optics has revolutionised our world. Fiber optics has made important contributions to the medical field, especially with regards to surgery. One of the most useful characteristics of optical fibers is their ability to enter the minute passageways and hard-to-reach areas of the human body. But perhaps the greatest contribution of the 20th century is the combination of fiber optics and electronics to transform telecommunications.

Fiber optic transmission has found a vast range of applications in computer systems. As we move towards a more sophisticated and modern future, the uses of fiber optics are increasing in all computer systems as well as telecommunication networks.

As new optical fibers are being made, many telecommunication companies are joining forces to share the cost of installing new network cables. In July 2009 and underwater fiber optic cable was put down along the East African coast by Seacom. New technologies are constantly being invented and video phones and video conferencing such as Skype are becoming an everyday occurrence in many businesses and households. Shopping from home via the internet and online stores such as Amazon.com and Kalahari.net are making many people’s lives easier. Even television on demand, such as being offered by DSTV, will replace the current cable television systems of today.

We live in a technological age that is the result of many brilliant discoveries and inventions. However, it is our ability to transmit information and all the media we use to achieve this that is responsible for this evolution. Our progress from using copper wire a century ago to modern day fiber optics that can transmit phenomenal loads of data over longer and longer distances at ever increasing speed has expanded the boundaries of our technological development in all spheres of life.