Theory of Light Relevant to Fiber Optics - Essay Example

?FIBER OPTICS al Affiliation) Theory of Light Relevant to Fiber Optics Light propagation transmission along the optical fiber can b described in two ways being light as a simple ray which is known as geometrical or the ray theory optics approach. In this theory the light is used in the approximation of the light acceptance and also as a guideline property to optical fiber (Hecht 1999, pg. 12). The next theory describes light as being an electromagnetic wave which is known as mode theory or the wave representation approach. In this theory, the behavior of light is able to be shown or rather described within the optical fiber. This theory is majorly used in describing the causes of attenuation, dispersion of light and also the optical fiber absorption. Construction of Fiber Optic Cables Fiber optic cables are first given the core size which is 50/125 as the diameter then followed by the cladding size which is 125 microns while the 8/125 has a core diameter of 8microns with a cladding diameter of 125microns.A larger diameter has a larger core which allows more light which can be coupled depending n the angle cone. They can ether operate on a single mode propagation or a multimode propagation. The fiber-optic cables are made up of either glass, plastic or plastic-clad silica which differ to its attenuation. Attenuation can be seen to be majorly caused by absorption or scattering. In the glass fiber optic cable it is seen to consist of the lowest attenuation which when made it consists of glass core and glass cladding. It is also the most common preferred and has spread worldwide as it is easy to install because most of the people have accessed to it. The glass used is pure mad of silicon dioxide which during its fabrication process the impurities are added in order for it to produce a desire refraction of light. Boron or Fluorine is also added to decrease the refraction index. Plastic fiber optic cable has the highest attenuation as compared to the others made of plastic core and cladding. The core is made up of the polymethymethacrylate and coated with fluoropolymer. It’s better to used considering its costs and also do not have the flammability effect. Plastic clad silica fiber optic cable attenuation is between the glass and plastic. Its fiber optic cable has glass core commonly vitreous silica and its cladding is plastic. Its use of the silica makes it have a lower refractive index. It is fabricated with silicone elastomeric cladding which causes difficulty in its application, plasticity and also it makes it insoluble in organic solvents which bar it from being used by most of the people. Basic Fiber Optic Cables This is the type f technology which uses glass threads in order to transmit information or data. The bundles of the glass threads used are the ones capable in transmitting information which is later modulated into light waves. It is majorly used because of its advantages over the metal cables used earlier regarding on speed which is high as compared to the other communication lines among other advantages like it being thinner and light in weight. Although they are advantageous they also are disadvantageous in that they are expensive in its installation and also fragile among others. Fiber optics are becoming common in the local area networking enabling companies being able to use this as a better communication way. Types of Fiber Optic Cable There are 2 main types of fiber optic cables; these are the single mode and multimode fiber optic cable. The single mode fiber optic cable (also referred to as uni-mode fiber, mono-mode fiber among other names) is used for a broad range of transmission as it covers longer distances making it suitable for multichannel television broadcasting system among other long distances transmission (Tricker 2002, pg. 20). This is caused by the ability to restore or allowance for a larger capacity for the transmission of information as it can retain the fidelity of light pulse. In this kind of fiber a lot of information is able to be sent in a specific unit of time as it can transmit up to fifty times more as compared to the multimode and can also propagate its wavelength at 1300 to 1320nm. This is because of the lower fiber attenuation as compared to the multimode fiber and the smaller core as compared to multimode. This therefore does not result in the overlapping of light pulses which increase the speed transmission and also leads to low signal attenuation. It has since improved to very complex designs as seen by the examples of clad and depressed clad among others. The multimode fiber optic is whereby light rays are taken at a time through the waveguide. It has a larger fiber core diameter which enables it to take a bigger number of modes and also makes it easier to couple as compared to single-mode optical fiber. A multimode fiber provides a bandwidth of the speed ten to a hundred megabits per second to gigabit and covers a distance of 275m to 2km.This is a very high speed as light waves dispersed are divided into numerous modes as the cable core of a multimode fiber optic is 850 or 1300nm.Although this can be seen as an advantage it leads to the signal distortion on the receiving end which may lead to incomplete transmission of data and also may be seen as unclear making single mode most preferred. Multimode fiber can also be categorized into step-index fiber or graded-index fiber. Sources and Detectors used in Fiber Optic Communication Fiber optic communication system is made up from the light, fiber and the detector. The light sources are divided into light-emitting diodes and the laser diodes. The light-emitting diodes made from aluminium gallium are much cheaper and also easier when using but its performance is lower as compared to laser diodes (Bass & Stryland 2002, pg. 26). The laser diode allows coupling more power of light as compared to the light-emitting diode to an optical fiber. The fiber optic system is the transmission system using light as an emitting source converting it to electrical impulses to which the mission are sent through the optical receiver in order to convert the intensities which are changing of light. The transmitter is used in converting optical fiber the medium being optical fiber cable. Attenuation in Fiber Optics Systems This is known as transmission loss seen by the reduction in intensity that is seen in the signal also light beam while travelling through the transmission medium. Its coefficients uses db/km units caused by the high quality of transparency in the optical transmission medium which is silica glass used to confine light beam to the inside. Attenuation in optical fiber is mainly caused by scattering, absorption and geometric effects. Light scattering is characterized by the reflection of light in different angles caused by the rough and irregular surfaces which lead to its random directions. This majorly depends on light wavelength being scattered which leads to effect on its visibility also depending on frequency f incident light-wave and also the physical dimension .Attenuation is led from the random scattering of the light at interfaces and also internal surfaces. The scattering of light has also been seen to have been caused by the molecular level irregularities seen in the structure or the composition of glass and the optical processes which are nonlinear in the fiber (Crisp 1996, pg. 31). Absorption is another cause of attenuation in fiber optics system as specific wavelengths are being absorbed which includes both electrons and molecules. Absorption depends on the electronic level as to how they can absorb in a wavelength light in visible ranges which leads to color. It also depends on frequencies of the atomic and chemical bonds on how they produce long range order. Geometric effects are seen to be of two types causing attenuation which is microscopic and macroscopic. Macroscopic is caused by large scale bending like pulling fiber around a corner. Microscopic on the other hand can be seen to occur when fiber is being sheathed within a protective cable which leads to axial distortions. Advantages of Fiber Optics over Copper Wire. A lot of data is able to be transmitted as compared to copper this is because of the optical fiber’s high bandwidth (Chomycz 2000, pg. 49). Through this people as an advantage of them by the internet which can transmit two telephone calls one at a time or over 80,000 that is using the single optical fiber. Optical fiber carries a high frequency signal as compared to copper which loses signal strength at higher frequency. Fiber optics uses glass while transmitting this thereby makes it cheaper as compared to copper which is costly. While using copper in its transmission, it will require the cable replacement which is costly. This cannot be experienced by the fiber optics as there is no need to replace the cables even with the improvement of bandwidths this is because of the technology improvement. Glass is a good insulator and so there will be no experience of electrical current being transmitted down the fiber making it secure in the environment especially where electrical discharge would be harmful. Fiber optic technology has reduced noise and electromagnetic interference as compared to copper as it is unaffected by the electro-magnetic interference especially when it requires a higher voltage equipment making it more favorable to the environment. References Bass, M., & Stryland, E. W. 2002, Fiber optics handbook fiber, devices, and systems for optical communications, New York: McGraw-Hill. Chomycz, B. 2000, Fiber optic installer's field manual, New York: McGraw Hill. Crisp, J. 1996, Introduction to fiber optics, Oxford: Newnes. Hecht, J. 1999 City of light: the story of fiber optics, New York: Oxford University Press. Tricker, R. 2002, Optoelectronics and fiber optic technology, Oxford: Newnes. .   Read More