Fiber Optics in Communication
A fiber is a flexible, hair – like strand of a substance and is the smallest visible unit of any textile product. It is very much long in relation to its width or at least one hundred times longer than it is wide. A particular fiber’s properties are dependent upon its physical structure and chemical composition. Manufacturers use fibers whose properties suit the products they market.
Citing for example, when used in clothing, fibers must specifically possess certain properties such that it must feel pleasant to the touch, it must be absorbent, the fiber must have a good luster, and last but not the least, the fabric must drape to fit the body. Spandex, one class of fiber has the ability to stretch like rubber. The durability and strength of a fiber are important specifically when it is used for industrial purposes. One particular fiber, SPECTRA – 900, is characteristically ten times stronger than steel (The World Book Encyclopedia, volume seven, p. 87).
Fiber optics, therefore is a branch of physics that is based on the transmission of light through transparent fibers of plastic or glass. The book further notes that optical fibers are capable of carrying light over long distances. The said distances can range from a little of few inches or centimeters up to more than one hundred sixty kilometers, or also equivalent to one hundred miles. These optical fibers either work individually or in bundles. There are some individual fibers whose diameter measures less than 0. 001 inch or also equivalent to 0. 025 millimeter (p. 88).
Optical fibers have extremely pure core of plastic or glass. Optical fibers are surrounded by an outer covering more commonly known as a cladding. Be it from any source as light bulb, or laser, the light enters just one end of an optical fiber. The cladding are designed such that bends inwards. Such is the direction so that light rays strike its inside surface. The cladding serves to keep the light inside as light travels through the core. A detector at the outer end of the fiber receives the light. These detectors are the photosensitive device or the human eye (The World Book Encyclopedia p.
88). Single mode and multi mode fibers are the two kinds of optical fibers. Single mode fibers have extremely small cores. As a light source, single mode fibers require the use of special lasers. Such condition is the result of their nature of accepting light only through the axis of the fibers. There is a need for these single mode fibers to be connected to the laser, the detector and the other fibers in the system in utmost precision. On the other hand, accepting light from a variety of angles, multi mode fibers have larger cores than that of its single mode counterparts.
Although multi mode fibers can use cheaper connectors and more types of light, they are not advisable to be used over long distances (p. 88). Optical fibers boast a number of uses. Coded messages are transmitted by special lasers by flashing on and off at extremely high speed in a fiber optic communication system. It is through the optical fibers where messages travel to interpreting devices that decode the messages. Such are then converted back into the form of the original signal. As opposed to the system that employs the use of traditional copper cables, there are a number of features that sets a fiber optic communication system apart.
One of these special features is that in a fiber optic communication system, there is a much larger information carrying capacity that is sparred to electrical interference. Moreover, there is a need for less amplification for signals sent over long distance fiber optic cables as opposed to the signals sent over its copper cable counterparts of equal length. Many telephone and other communication companies, made aware of these things has begun to take a shift from using copper cables to fiber optic cables ( p. 89).
Fiber optics, is the branch of physics has made it possible to employ light to send messages than otherwise could be done by using radio waves or electricity. In the future, there may be many forms of energy, light – waves, lasers, devices that produce a narrow beam of intense light involved in making communication over long distances possible. A laser beam transforms the electric signals of a TV picture telephone call into light impulses, in a fiber optic communication system. The laser is aimed into one end of the optical fibers, which are transparent and thin glass strands.
Each fiber are so thin that it is just about the thickness of a human hair. A light can travel to great distance through these fibers making it possible to transmit thousands of TV programs or telephone calls all at the same time (The World Book Encyclopedia, volume 4, p. 888). The article entitled “Modern Communication: The Laser and Fiber – Optic Revolution,” provided by the National Academy of Sciences states that it is in the branch of physics called quantum mechanics that the research that would give rise to the laser can dig its origins.
The theory of electromagnetic radiation was prevalent during the 1900. It states that atoms radiate as a continuous range of energy. Max Planck opposed this theory. According to the hypothesis developed by Planck, atoms radiate in discrete packets. He came to call these discrete packets s quanta. After five years, Albert Einstein pursued the implications of the notion developed by Planck as the later never did. Einstein suggested that light itself was made up of packets of energy, and not waves. He coined the name photons to refer to these certain packets of energy.
According to Einstein’s theory, the higher the frequency of the light, the more energetic is the photon. Later on, Einstein demonstrated how electrons could absorb and emit the energy of photons under some conditions. He used the demonstration to explain the photoelectric effect, which is the discharge of electrons from matter by their impact of radiation, especially visible light. This breakthrough earned him a Nobel Prize. Meanwhile, Einstein was not able to solicit everyone’s approval in his theory pf light – as a particle. It has even ignited a debate that continued for a couple of decades long.
But this did not stop Einstein to discover yet another phenomenon. He was set to such new discoveries even while physicists are on the way to accepting that light was somehow both a particle and a wave. In reference to Neil’s Bohr model of an atom, determined by the electron’s energy levels, electrons occupy specific orbits around the nucleus. His model was published in a series way back in 1913. An electron, according to Bohr, can only absorb only the exact amount of energy needed to kick it from one orbit up to a specific higher one. It emits a specific amount of energy on dropping an orbit to a lower one.
This gives us an understanding why neon’s atoms emit a pattern of wavelengths that distinctive. Also it answers the query why sodium and mercury’s discharge lamps have a color characteristic of each. There is a process called “stimulated emission. ” The concept explains that atoms in an excited state, when their electrons are higher – energy orbits – will eventually and spontaneously fall back to is ground or lowest state while giving off the stored energy while in the process. This emission occurs at random in a given system of atoms. The emitted photons of energy head off in random directions.
Einstein describes that in an encounter when atoms in an excited state meet photons of light with the right amount of energy, it can trigger a kind of chain reaction of emission. The right amount of energy he is taking about is an amount equal to the difference between the lower – energy states and the higher energy states. Such emission will boost the intensity of the light that passes through. The electrons will drop the ones that they have stored up in their greedy attempt to capture the incoming ones. The incoming photons are headed in the same direction as the emitted photons (p.
1). A population inversion is required for stimulated emission. This is because it is not a normal situation when more atoms in the population of atoms were in an excited state than in the lower – energy state. It is actually the exact opposite of their normal situation. In a population inversion, there would be an artificial boost to the entire population of atoms to an excited state. An artificial boost can be made possible by the exposure of atoms to light (p. 5). A research on microwave Physics that began during the Second World War saw a continuation during the year 1951.
It was Charles Townes, who was also the head of the Columbia University who headed the continued research on the topic. Townes was working on the subject of microwave spectrospy. He was also eager to use short wavelengths in the sub – millimeter range. The mechanical oscillators that are being used then for the generation of microwaves in the centimeter range found a need to be scaled down. Not until Townes thought of using molecules did this not post to be a problem (The National Academy of Sciences, p. 5). Together with Herbert Zeiger and James Gordon, Charles Townes worked to build such a system on the two years that followed after.
It was during the late 1953 when the three were able to demonstrate the result of the research they made. A beam of ammonia sent through an electric field that deflects molecules that were in a low – energy state. High – energy molecules are sent onto another electric field. All the high – energy ammonia molecules simultaneously drop to the ground state as result of their exposure to the second field. Microwave photons that travel in the same direction and were all at the same frequency are then emitted. Townes coined the word maser for this device.
This device is for the amplification of microwave by a stimulated emission of radiation. Experiments on maser continued to spark the interest of Townes. By his experiments an idea came clear to Townes. The idea is that with much work with the much shorter wavelengths of infrared and even of visible light, there is a possibility that stimulated emission could work. The term “laser” was coined for the device. The letter “l” stands for “light. ” Arthur Schawlow, the brother – in – law of Townes was sought by the later to help him in his quest to develop a more complete theory of laser action.
Schawlow was then a physicist at Bell Laboratories. The company Schawlow was associated to is one of the nation’s leading centers for materials and research (The National Academy of Sciences, p. 5). The paper entitled “Infrared and Optical Masers,” written by Townes and Schalow graced the pages of a leading physics journal named Physical Review in the year 1958. Scientists were inspired by the paper to try to build a laser device. Theodore Maiman, a physicist at the research laboratory at Hughes Aircraft Company, succeeded as he came to use synthetic ruby back in June in the year 1960 (Ibid, par.
9). There has been an immediate interest has been attracted by laser, the ones that are emitting much more highly focused light beams than other light sources. In the year 1962, an experiment was performed using a 1 – foot diameter laser beam aimed at the moon. The earth is 240,000 miles away from the moon. The laser beam was able to illumine only two miles in diameter of surface area. In traveling the same distance, a beam of ordinary light would spread so much than it would illumine a 25,000 miles in diameter of an area. The journalists took the new technology with utmost enthusiasm.
They wrote about “light fantastic. ” They were the ones who hailed lasers as the harbingers of the new age. In the James Bond movie entitled Goldfinger, lasers were featured by film – makers to be the weapons of doom. Scientists were quick to point out the enormous promise of lasers in the world of communication as well as in other fields (Ibid, par. 10). To be able to meet such expectations, early lasers still have a long way to go. The so – called optical lamps, such as flash lamps are required in the creation of the population inversion that is necessary to be able to generate laser action.
These optical lamps could only produce a pulse of energy. They could not possibly produce a continuous laser light. Optical lamps will not serve to be efficient in the use of power. Yet another version, a glass tube which contains a mixture of helium and neon gases were developed by Ali Javan at the Bell Laboratories in 1960. The laser developed by Javan did not overheat. It even has a lower energy threshold. However, the glass tube proved to be both fragile and bulky. The ones being used in the first computer, radio and television sets are lasers that resembled the vacuum tubes.
The amazingly small and highly reliable transistors were given way be these vacuum tubes in the year 1960. There was still no certainty, though if lasers could indeed make the same transition (p. 5). The moving electrons are the ones that carry electric current. Ordinary metals like copper are good conductors of electricity. Coppers are good conductors because their electrons are not tightly bound to the nucleus of the atom. This makes it possible for them to freely attract positive charges. Insulators like rubber and other substances are poor conductors of electricity.
They are considered to be poor conductors since their electrons do not move freely. As the name implies, semiconductors fall somewhere in between. Semiconductors ordinarily behave like insulators. They can be made to conduct electricity under some conditions (p. 6). The same old problem of overheating still poses a threat. GaAs are lasers that use a single semiconductor are not very efficient. So much electricity is still required for them to be able to initiate laser action. They quickly overheat at normal room temperature. The only option is to employ a pulse operation.
Such operation does not prove to be practical for communication. Many scientists tried to place lasers atop other materials that were good heat conductors in their attempt to remove the heat. However, such were failed attempts. It was in the year 1963 when the University of Colorado’s Herbert Kroemer proposed a different approach. Kroemer’s approach is to build a laser that consists of a semi – conductor sandwich, with a thin active layer that is set between two slabs of different material. Very little current is required to confirm the laser action to the thin active layer.
The heat output can also be kept at manageable levels (Ibid, par. 11). These information were taken from the article entitled “Modern Communication: The Laser and Fiber – Optic Revolution. ” The challenge of transmitting light signals across long distances remained. Radio waves of long wavelength are traveling freely through the air. They pierce fog and heavy rains with so much ease. Laser light of short wavelengths bounces off the atmospheric water vapor and other particles to such degree that leaves it either blocked or scattered. A laser connection link can be cut off during a foggy day.
A light then needs to have a conduit. One that is analogous to the telephone lines (p. 6). One approach can be offered by optical fibers. During the mid – 1960s there is certainty in the fact that the answer lays on the direction of optical fibers. Serious consideration was also given to other possibilities. The total internal reflection is a property that makes it possible for light to be channeled in glass fibers. As early as in 1820, Augustine – Jean Fresnel already know about the equation governing the trapping of light inside a flat glass. In the year 1910, Peter Deybe and D.
Hondros provided the extension to what were then known as glass wires. The year was 1964, when Stewart Miller deduced the ways to probe the potential of glass as an efficient long – distance transmission medium at the Bell Laboratories (p. 7). A significant turning point has been marked by these activities. Mean do now exist to take the giant leap of bringing the fiber optic out of the physics laboratory and allow it to grace into the realm of mainstream engineering. Research continued over the next decade. Through the course of time, and increased in transparency has been made in optical fibers.
It was in the year 1980 when the best fibers produced were so transparent that the fibers became to weak before a signal that might pass through 150 miles was able detected. One can sail across the deepest and darkest part of the Pacific to be able to see the ocean floor as easily as he could the bottom of a swimming pool. It could be possible if only the world’s sea were that clear (p. 7). A rapid and remarkable progress is certainly made clear. The accomplishments that have occurred are really impressive. But over the future horizon, there exists even more greater and dramatic advances in the communication technology.
Fiber optic systems of today serve as trunk lines. They carry large number of voice and data channels between central telephone stations. The last mile from the central station to your home is the subject of today’s industry specialists. The conventional copper wire equipment spans the last mile in today’s telephone system. Though it provides good voice connections, the conventional copper wire equipment still proves to be inadequate to carry large quantities of high – speed data (p. 7). It was in the year 1870 when Alexander Graham Bell though of using visible light as a medium for communication.
Back then Bell did not have a way to generate a useful carrier frequency. He did not have a way to transmit the light from point to point. More than 40 years earlier before the practical fruit with the invention of the laser, Einstein introduced the idea. The year was 1960. It has been an understated achievement. It has caused scientists to find a way to make visible light a medium of communication. Not so long after, fiber optics began to arrive (p. 8). As a solution for the problem concerning the last mile, high – speed date lines has already been made available.
Although high – speed data lines are generally more expensive than is practical for home use today, most businesses have them. The research will have to come from scientists who probe beneath the immediate needs of any given industry. They are the mighty ones who investigated the otherwise seemingly unrelated process in the search for an understanding of the fundamental natures of the world. They remain to be the leaders of the search towards the new technology that will turn out to provide the last crucial link for individuals to the rest of the world and maybe beyond (p. 10).
A simultaneous transmission of 36 telephone conversation was made possible by the first transatlantic copper wire cable. Back in the year 1956, such event is a cause for celebration. In today’s day and age, the number seems paltry. Soon, other cables followed the lead. It was in the early 1960s when another milestone happened in the industry of telecommunication. An average of 5 million per year in overseas telephone calls has been reached. In the mid – 1960s, satellite communication has been made possible. Two hundred million overseas calls per year have been carried by the telephone systems of 1980.
Nevertheless, there will still be an increase in the demand on the telecommunication system. Apparently, there has been a limitation of current technology. The quest to find the Holy Grail of communication has seen its fruition come the year 1980s. As a way to communicate, we have to harness light itself (The National Academy of Sciences, p. 10). The Federal Communications Commission made a number of important decisions since the late 1960s. Such decisions may lead to greater competition among the players involved in the U. S. telephone industry.
In a separate case, the commission ruled that the people may be allowed to purchase and install their own the telephones and other equipment (The World Book Encyclopedia, volume 19, p. 105). It was in the year 1970 when the International Direct Distance Dialing (IDDD) began its operation between the cities of New York and London. IDDD enables people to dial overseas directly. Today, several cities around the globe have been served by IDDD. In Atlanta, back in the year 1980, fiber optic system for the transmission of local calls has been installed.
Telephone conversation travels on a beam of light through hair – thin strands of glass in a fiber optic system (Ibid, par. 14). The World Book Encyclopedia volume 19 further notes that, liscenses for the building and operation of mobile telephone systems based on cellular radio technology has been granted in the year 1982 by FCC. A city is divided into districts or cells in a mobile telephone system. Each cell has a low – powered radio transmitter and receiver. A computer transfers a cal from one transmitter and receiver to another as a phone – equipped car travels from cell to cell.
This happens without interruption in the conversation. Earlier systems used one high – powered transmitter and receiver for an entire city. As compared to earlier systems, cellular mobile telephone service is able to handle remarkably more cells than the former (105). Back in 1982, the AT&T has been charge with anticompetitive practices. The company then settled on a lawsuit with the U. S. government. The company agreed to give up on its ownership of the local telephone operating companies. AT&T did so to be able to be allowed entrance in the computer services and information – processing businesses (p.
106). The advent of the fiber optic technology has indeed taken a sharp turn in the world of communication. As recent as 10 years ago, the world – shrinking and instantaneous communication is far from reality. During that time, critical pieces of technology in both communication and computing are just beginning to emerge. It was not until the year 1988 when the very first transatlantic fiber – optic cable has been laid. It was just then when the “information superhighway” has begun to pave the way for making such communication made possible (The National Academy of Sciences, p. 10).
Telecommunication is the transmission and reception of messages over long distances. The earliest forms of telecommunication are smoke, lamps and visual signaling with flags. A wide variety of electrical and electronic communication systems that transmit information around the world is what we now refer to as telecommunications. Visual images, printed material, the sending and receiving of sound in a fraction of a second are made possible by modern telecommunication systems (p. 93). Radios, television sets and telephones are among the common communication systems available in the world today.
In the industry, other kinds of systems are chiefly used. Airline reservations, stock market reports and banking transactions are transmitted by these systems. To be able to obtain photographs and new stories from all around the world, telephoto equipment as well as teletypewriter are relied upon by newspapers. With the aid of telecommunication, the establishment of the communication link between the earth and the space stations has been made possible (The World Book Encyclopedia, volume 19, p. 93). Basically, all forms of modern communication rely on a carrier signal.
This particular carrier signal is a wavelike electromagnetic oscillation with a particular frequency. These forms of modern communication include computer data, radio and television signals as well as telephone conversations. Wavelength of the distance between the peaks of two waves; or the frequency expressed in Hertz, is the number of wave cycles per second, are the ones that describe electromagnetic signals. The frequency is high if the wavelength is short. The information to be transmitted can be encoded by modulating the carrier. The more signal can be held if the carrier frequency is high (p.
4). A frequency of one million cycles second, or also equal to 1 megahertz, which is enough to carry few dozens of voice channels, is the limit of a copper wire. A copper wire’s electrical resistance increases substantially at higher frequencies. After the Second World War, coaxial cables became predominant. These cables consist of a solid conductor placed inside a hollow one. It serves to channel the signals between them. It also serves to shield it from interference. Coaxial cables, carrying a frequency of 10 billion cycles per second or 10 gigahertz were used for trunk lines between cities.
But such cables are expensive to span long distances. In terms of information – carrying capacity per channel, there has been a failure on the part of earthbound microwave systems operating at frequencies amounting up to 40 gigahertz. The failure in terms of reaching the practical limit of their information – carrying capacity per second also happened in the case of satellites (The National Academy of Sciences, p. 4). Messages are transmitted by radio, wire or satellite in the case of most telecommunication system in the world today.
It is through the wires that are laid underground in cables where telephone conversations, most especially local calls as well as telegraph messages travel. The cables that run across the ocean floor are the ones that handle communications that travel overseas. The radio waves are the ones that send the radio and television broadcasts signals through the air. Microwaves are radio waves that are responsible for the transmission of signals over extremely long distances. In most long distance telephone communication, the use of microwaves is also employed.
Television, telephone and all the other communication signals are being transmitted through the aid of what we call communication satellites that orbit around the earth (p. 93). Analogue transmission and digital transmission are the two methods of two methods of telecommunication transmission. On the one hand, signals which are the exact reproductions of the picture or sound being transmitted is used in the analogue method. In an analogue telephone system, an electric current transmits and copies the pattern of sound waves of the speaker’s voice.
As the electric current travels over the wire, it is converted back to sound waves in the telephone receiver (p. 93). On the other hand, signals are converted into a code in the case of digital transmission. In most cases, there are two elements of the code. These two elements are the dot – dash of the Morse code or the on – off flashing of a light. The coded signals are being transmitted by a rapidly flashing beam of light, as in the case of one type of the digital telephone system. The signals are decoded in the receiver.
The laser is a device that produces light travels through the thin strands of glass or what we refer to as optical fibers (p. 93). The light in the system flashes on and off for about forty – five million times per second when it is in the process of transmitting a telephone conversation. Two optical fibers are able to carry conversations amounting to 6,000 at the same time thanks to the high rate that makes it possible. To be able to handle as many conversations, it would take 250 copper wires. When compared to an analogue system, less distortion and noise.
Aware of these advantages caused the conversion of many telecommunication systems from analogue transmission to digital transmission (The World Book Encyclopedia, volume 19, p. 93). A laser can transmit television signals and voice messages. Ordinary electronic transmitters such as the ones used to produce television and radio signals fail in comparison over lasers in communication. One of laser light’s great advantages over radio waves are that its laser beam can carry much more information because of its high frequency.
Laser beams can possibly transmit many television programs and telephone calls at the same time than radio waves ever can (p. 83). Since it is able to produce highly directional beam, a laser can transmit information with little interference. It is possible to direct a laser beam such that it falls solely on the desired laser – receiving equipment. Most interference is eliminated since it is only the laser beams that are received by the equipment. It is also because of this high directional beam of laser that makes it efficient to be used in long distance transmissions.
Unlike radio waves, laser beams spread slightly as they travel. The promise of these laser beams is the source of hope among scientist that one day, they may aid in the realization of an excellent communication link between submerged submarines and spacecrafts (p. 83). The possibility of sending a laser beam that carries communication signals form one relay station to another through a long glass fiber is realized through a branch of physics that came to be called Fiber Optics. With little loss of clarity and energy, the beam that is reflected through the glass fibers is able to travel significantly great distances.
Some videodisk and compact disk players, high – speed printers and photocopiers and other communication devices employ the use of lasers (The World Book Encyclopedia, volume 12, p. 83-84). In the modern society, fax machines, cellular phones and cyberspace are almost a way of life. Lasers and fiber optics are the technological breakthroughs that all these things rely upon. Experimental efforts aimed to produce a fiber that has a dramatic decrease in the light loss in glass fibers happened. Scientists continued to explore the possibilities and techniques to be able to decrease light loss in optical fibers.
Soon, fiber optic communication has left the confines of the science laboratories and was given a red carpet entrance into man’s everyday life. This did not stop researchers in their attempt to continue to improve the laser technology. It was in the year 1970 when fiber optic systems have been employed for commercial use. Research on the possible improvements in the systems did not wane even while fiber optic cables are already being used the world over. Scientists are aware that there still exist many more possibilities for improvement in high – speed data lines.
They know too well that those possibilities are looming over them on the vast horizon (The National Academy of Sciences, p. 4). Optical communication systems trace quite a long history. Our ancestors relay messages from one mountain to another through smoke and fire. There is only a limited transmission capacity in this form of optical communication. This type of scheme can serve as a warning. For example, history would have it that Queen Elizabeth the First of England planned to set an event of a sea – borne invasion from Spain when she erected a network of bonfire.
The Native American’s smoke signals are capable of transmitting various messages. Semaphore, which is the use of flags to indicate that a letter has been transmitted one at a time, had been instrumental in the passing of messages back in the eighteenth century. At a rate of one letter per second over a direct line of sight, a semaphore can transmit the information. In this form of communication, messages can also be relayed over long distances. A semaphore as a means of communication poses security risks.
If a person in the line of sight to the message sender has an understanding of the code, he can read the information. There is also a possibility of interception and alteration of messages during the relay process in this form of communication (Ball 55). In the global telecommunication system, it is the optical fibers. Although these fibers a just about glass strands thinner than the human hair, are designed to be capable of transmitting data via relatively new form of light that are focused tightly on laser beams.
These glass strands are characteristically stronger than steel. The capacity of international telephone systems has witnessed a dramatic increase thanks to the remarkable tandem of laser and optical fibers. The growth of the phenomenon that came to be called the Internet of cyberspace has been ignited by the new communication technology. It has been made possible by the noteworthy improvements that have happened in the communication technology (The National Academy of Science, p. 4). In the article provided by the Telecommunications Industry Association entitled “AboutSample Essay of BuyEssay.org