Fiber Optics TechnologyEngr. Leah Q. SantosFaculty, Engg - EcE dept.Objectivese!ne optical co""unications#resent an overvie$ o% the history o% optical !ber&o"pare the advantages and disadvantages o% optical !bers over "etallic cablese!ne electro"agnetic %re'uency and $avelength spectru"escribe several types o% optical !ber construction E(plain the physics o% light and the %ollo$ing ter"s) velocity of propagation, refraction, refractive index, critical angle, acceptance angle, acceptance cone, numerical apertureObjectivesescribe ho$ light $aves propagate through an optical !ber cable.e!ne "odes o% propagation and inde( pro!leescribe the three types o% optical !ber con!gurationsescribe the various losses incurred in optical !ber cablese!ne light source and optical po$erescribe the %ollo$ing light sourcesescribe the %ollo$ing light detectorsescribe the operation o% a L*SE+E(plain ho$ to calculate a lin, budget %or an optical !ber syste".-here .t StartedTyndalls /istorical E(peri"entWhat was expectedto happen?What actually happened?Light &an 0o *ny$hereLight 0uiding *pplications+oad SignsEndoscopes /a1ardous *reas*ll at Sea&o""unications&o""unicationsAlexander Graham Bell Photophone#hotophone2ses light %or the trans"ission o% speech. .t $as a tube $ith a 3e(ible "irror at its end. /e spo,e do$n the tube and the sound vibrated the "irror. The "odulated light $as detected by a photocell placed at a distance o% t$o hundred "eters or so.The result $as certainly not hi-! but the speech could at least be understood.Fiber Optics Technology Optic Fiber is the transparent "aterial, along $hich $e can trans"it light. Fiber Optics is the syste", or branch o% engineering concerned $ith using the optic !bers. Optic !ber is there%ore used in a !ber optic syste". Fiber is a %riendly abbreviation %or either, so $e could say that !ber is used in a !ber syste".Father o% Optical Fiber Dr. Narinder Singh apany !oined the term "#i$er %ptics in &'()*FiberscopeHeel, Hopkins and Kapany- .n 4567s they e(peri"ented $ith light trans"ission through bundles o% !bers. .t led to the develop"ent o% the 3e(ible !berscope. A fiberscope is a +lexi$le +i$er optic $undle with an eyepiece at one end, and a lens at the other. -t is used +or inspection wor., o+ten to examine smallcomponents in tightly pac.ed e/uipment, when the inspector cannot easily access the part re/uiringinspection.#rinciple o% OperationThe syste" is basically very si"ple) a signal is used to vary, or "odulate, the light output o% a suitable source 8 usually a laser or an LE 9light e"itting diode:. The 3ashes o% light travel along the !ber and, at the %ar end, are converted to an electrical signal by "eans o% a photo-electric cell. Thus the original input signal is recoveredA simple +i$eroptic system;loc, iagra". +e"ote electrical po$er?. Susceptible to losses introduced by bending the cable6. Speciali1ed tools, e'uip"ent and training.Electro"agnetic Spectru"#i$er optics used 0isi$le light and in+rared0eneral SubdivisionLight is an electro"agnetic $ave having a very high oscillation %re'uency and very short $avelength.a. Infrared C ;and o% light $avelengths that are too long to be seen by the hu"an eye. 9AA7 n" to 477,777 n":b. Visible Light C ;and o% light $avelengths to $hich the hu"an eye respond 9>57 n" to AA7 n":c. Ultraviolet C ;and o% light $avelengths that are too short to be seen by the hu"an eye 947 n" to >57 n":*ngstro" D Eicrons-hen dealing $ith light %re'uencies, it is co""on to use units o% $avelength rather than %re'uency.-avelength is o%ten stated in "icrons $here 4 "icron F 47-@ "eter 94u": or in nano"eters 4n"F47-5. -hen describing the optical spectru", the unit angstro" is so"eti"es used to e(pressed $avelength $here 4 angstro" F 47-47 "eters, or 7.774 "icron. Gature o% LightAlbert Einstein!a" #lanck C sho$ed that $hen light is e"itted or absorbed, it behaves li,e an electro"agnetic $ave and also li,e a particle, called a photon, $hich possess energy proportional to its %re'uency. #lanck$s La% C Hwhen visible light or high frequency electromagnetic radiation illuminates a metallic surface, electrons are emitted#lanc,s La$Ep1 energy o+ the photon 23oules4h1 Planc.5s constant1 ).)6( x &789: ;8sf1 +re/uency o+ light 2photon4 emitted 2herte+raction Prismatic >e+raction+e%ractive .nde(n 1 re+racti0e index 2unitless4c 1 speed o+ light v 1 speed o+ light in a gi0en material 2m?s4.nde( o% +e%ractionSUBSTANCERefractive Index @acuum &.7777Air &.7779-ce &.97'Water &.99Athyl Alcohol &.9)Bagnesium #luoride &.9CGlass 2+used /uarts4 &.:)Glass 2crown4 &.(6Sodium !hloride &.(:Diamond 6.:6Snells La$/o$ a light ray reacts $hen it "eets the inter%ace o% t$o trans"issive "aterials that have diLerent inde(es o% re%raction can be e(plained $ith Snells la$. Snells La$&ritical *ngleEini"u" angle o% incidence at $hich a light ray "ay sti,e the inter%ace o% t$o "edia and result in an angle o% re%raction o% 57 degrees or greater. *cceptance *ngleGu"erical *perture 9G*:Figure o% "erit co""only used to "easure the "agnitude o% the acceptance angle. escribe the light gathering or light-collecting ability o% an optical !ber. E(peri"ent0elatin as !ber optic