Discus Fiber Optic Cables (Essay Sample)

Students Name:
Teachers Name:
Department: Information Technology
Admission Number: T/1079/2013
Fiber-optic communication: This method of transmitting information from one destination to another by sending light pulses through an optic fiber. When the light is send it forms an electromagnetic carrier wave that is modulated to carry information.
HISTORY
Fiber optic being one of the most used ways of modern internet connection is still one of the oldest inventions of connection technology. It was first introduced by Daniel Colladon and Jacques Babinet in the city of Paris in early 1840s. 12 years later John Tyndall one of the scholars who had been doing further researches about fiber optic gave a public lecture demonstrating how the fiber optic technology worked. "When the light pass from air into water, the refracted ray is bent towards the perpendicular when the ray passes from water to air it is bent from the perpendicular... If the angle which the ray in water encloses with the perpendicular to the surface be greater than 48 degrees, the ray will not quit the water at all: it will be totally reflected at the surface.... The angle which marks the limit where total reflection begins is called the limiting angle of the medium. For water this angle is 48°27', for flint glass it is 38°41', while for diamond it is 23°42'”( John Tyndall 1870)
In 1880 Alexander Graham Bell and Sumner Tainter came up with the Photophone an invention which was made in the Volta Laboratory in Washington, D.C., the Photophone was made to transmit voice signals over an optical beam. Unlike the earlier inventions which only had the power to transmit image the Photophone could transmit sound and this made it one of the greatest inventions of its time. Just like any other invention it had some failures and it seemed to be affected by atmospheric interferences and impractical until the secure transport of light that would be offered by fiber-optical system. In the late 19th and early 20th centuries, light was guided through bent glass rods to illuminate body cavities. In 1963 Jun-ichi Nishizawa, a Japanese scientist at Tohoku University, proposed the use of fiber optic for communication and this was stated in his book which was published in India in 2004. Jun-ichi Nishizawa invented other technologies that contributed to the development of optical fiber communications, such as the graded-index optical fiber as a channel for transmitting light from semiconductor lasers. Manfred Borner a German physicist came up with the first working fiber-optic data transmission system at Telefunken research Labs in 1965, which was followed by the first patent application for this technology in 1966. Charles K. Kao and George A Hockham of the British company Standard Telephone and Cables were the first to back up the idea that attenuation in fiber optic could be reduced to 20 decibels per kilometer and below this making fiber optic a reasonable communication medium. They proposed that the attenuation in fibers available at the time was caused by impurities that could be removed, rather than by fundamental physical effects such as scattering. They correctly and systematically theorized the light-loss properties for optical fiber, and pointed out the right material to use for such fibers silica glass with high purity. This discovery earned Kao the Nobel Prize in physics in 2009.
NASA used fiber optics in the television cameras that were sent to the moon. At the time, the use in the cameras was classified confidential, and only those with the right security clearance or those accompanied by someone with the right security clearance were permitted to handle the cameras.
TECHNOLOGY
Modern fiber-optic communication systems generally include an optical transmitter to convert an electrical signal into an optical signal to send into the optical fiber, a cable containing bundles of multiple optical fibers that is routed through underground conduits and buildings, multiple kinds of amplifiers, and an optical receiver to recover the signal as an electrical signal. The information transmitted is typically digital information generated by computers, telephone systems, and cable television companies.
HOW IT WORKS
Fiber optic cables are replacing copper wiring to increase the speed of digital information transmission. These cables are bundles of extremely pure glass threads that have been coated in two layers of reflective plastic. A light source typically a laser switches on and off rapidly at one end of the cable to transmit digital data. The light travels through the glass strands and continuously reflects off of the inside of the mirrored plastic coatings in a process known as total internal reflection. Systems based on fiber optics can transmit billions of bits of data per second, and they can even carry multiple signals along the same fiber by using lasers of different colors.
TYPES
1 Multimode fiber: This was the first to be manufactured and commercialized, simply refers to the fact that numerous modes or light rays are carried simultaneously through the waveguide. Modes result from the fact that light will only propagate in the fiber core at discrete angles within the cone of acceptance. This fiber type has a much larger core diameter, compared to single-mode fiber, allowing for the larger number of modes, and multimode fiber is easier to couple than single-mode optical fiber. Multimode fiber may be categorized as step-index or graded-index fiber.
Single-mode: This fiber allows a higher capacity to transmit information because it can retain the fidelity of each light pulse over longer distances, and it exhibits no dispersion caused by multiple modes. Single-mode fiber also enjoys lower fiber attenuation than multimode fiber. Thus, more information can be transmitted per unit of time. Like multimode fiber, early single-mode fiber was generally characterized as step-index fiber meaning the refractive index of the fiber core is a step above that of the cladding rather than graduated as it is in graded-index fiber. Modern single-mode fibers have evolved into more complex designs such as matched clad, depressed clad and other exotic structures.
ADVANTAGES OF FIBER OPTIC
1 Noise Resistance: Immune to EMI.
2 Less Signal Attenuation: Signals can run for miles without needing regeneration.
3 Higher Bandwidth: Can support a higher bandwidth than any other cable. 100Mbs-1Gbps.
DISADVANTAGES OF FIBER O...