A GROUP ASSINGMENT SUBMITTED BY:- DIPANKAR ACHARJEE RIMMI KONWAR RAJESH KAKATI SWAPNA BHUYAN ANKIT BARUAH DIMANTA BHARALI
Fibre optic communication has revolutionised thetelecommunications industry. It has also made its presencewidely felt within the data networking community as well.Using fibre optic cable, optical communications haveenabled telecommunications links to be made over muchgreater distances and with much lower levels of loss in thetransmission medium and possibly most important ofall, fiber optical communications has enabled much higherdata rates to be accommodated.As a result of these advantages, fibre optic communicationssystems are widely employed for applications ranging frommajor telecommunications backbone infrastructure toEthernet systems, broadband distribution, and general datanetworking.
TOTAL INTERNAL REFLECTIONWhen light traveling in an optically densemedium hits a boundary at an angle largerthan the "critical angle" for the media, thelight will be completely reflected. This iscalled total internal reflection..Fiber opticcables use total internal reflection insidethe optical fiber. The light enters the opticalfiber,and every time it strikes the edge of thefiber it experiences total internal reflection.This way the light travels down thelength of the optical fiber.
PROPAGATION There are two main categories of optical fiber used in fiber optic communications and are:Single mode optical fiberMulti mode optical fiber
SINGLE MODE OPTICAL FIBERThis mode of optical fiber areused to transmit one signal perfiber (used in telephone andcable TV). They have smallcores(9 microns in diameter) andtransmit infra-red light from laser.Single-mode fiber’s smaller core(<10 micrometers) necessitatesmore expensive components andinterconnection methods, butallows much longer, higher-performance links.
MULTI MODE OPTICAL FIBREThis type of optical fiber are usedto transmit many signals per fiber(used in computer networks).They have larger cores(62.5microns indiameter) and transmit infra-redlight from LED.However, multi-mode fiberintroduces multi-mode distortionwhich often limits the bandwidthsand length of the link.Furthermore, because of itshigher dopant content, multimodefiber is some what moreexpensive.
Core-thin glass center of fiber where light travels. Cladding-outer optical material surrounding the core. Buffer coating-plastic coating that protects the fiber.
APPLICATIONS CATV(cable television) services are supplied via a fiber optic network to an optical node, which converts and distributes the electrical signal to subscribers via a coaxial cable connection. CATV applications utilizes both single mode and multimode signals within different areas of the network. Single Mode fiber is used to distribute signal from the central office to optical nodes, where it can be converted to multimode Data transmission fiber optics, simply put, is the sending and receiving of data from point-to-point via a network. It ranges from very simple cables connecting servers or storage arrays inside a network or telecommunications system, to large multi-fiber distribution cables supporting intra-building connectivity and beyond.
INTERNET : Bandwidths of up to 10Gbps , Streaming Movies in HD(High Defination), Effortless video conferencing with no lagging , Gaming and so on….. The Independent Telecommunication Providers segment is an area of the industry that provides service(s) in rural areas, typically supporting residential and small to medium businesses. The services offered in these areas can range from basic telephone to triple play depending on the provider, subscriber location, and service availability. Expanded service can include television broadcast (high definition in some cases), VoIP (voice over internet protocol) phone service, and security over a single broadband connection. However, more and more of these various services are becoming available in rural locations nationwide.
ADVANTAGES Much higher bandwidth(Gbps) - Thousands of channels can be multiplexed together over one strand of fiber Immunity to noise - Immune to electromagnetic interference (EMI). Saftey-Doesn’t transmit electrical signals, making it safe in environments like a gas pipeline. Security - Impossible to “tap into.” Attenuation –It is a term that refers to the reduction in the strength of a signal. (fibers can be made to have only 0.2 dB/km of attenuation) Reliability - More resilient than copper in extreme environmental conditions. Size- Lighter and more compact than copper.Unlike impure, brittle glass, fiber is physically very flexible.
DISADVANTAGESDisadvantages include the cost of interfacingequipment necessary to convert electricalsignals to optical signals. (opticaltransmitters, receivers) splicing fiber opticcable is also more difficult.•Expensive over short distance•Requires highly skilled installers•Adding additional nodes is difficult
A huge amount of development can be made bymaking further research and work on fibre optics.We need it for a faster and more sophisticatedinfrastructure which would be the prime demand ofthe ever growing population of tomorrow. At present there are many optical fibercommunication links throughout the world withoutusing optical solitons. When we introduce opticalsolitons as light pulses through the fibers, we canachieve high quality telecommunication at a lowercost. We can expect a great revolution in opticalfiber communication within a few years by meansof solitons.
REFRENCES  T Okoshi and K Kikuchi, Coherent optical fibercommunication (Kluwer Academic, Boston)  A Hasegawa, Optical solitons in fibers (Springer Verlag,New York)  S E Millar and I P Kaminow, eds, Optical fibertelecommunications - II (Academic, New York)  G P Agrawal, Nonlinear fiber optics (Academic, NewYork)  C Yeh, Handbook of fiber optics (Academic, New York,1990)  G P Agrawal, Fiber optic communication systems (JohnWiley, Singapore, 1993)  N S Bergano and C R Davidson, Wavelength divisionmultiplexing in long-haul transmission systems, J. Lightwave Tech. 14, 1299 (1996)