Table Of Content

FABRICATIONOFGRADED-INDEX PLASTICOPTICALFIBERBYTHE DIFFUSION-ASSISTEDCOEXTRUSIONMETHOD ’ I By IN-SUNGSOHN ADISSERTATIONPRESENTEDTOTHEGRADUATESCHOOL OFTHEUNIVERSITYOFFLORIDAINPARTIALFULFILLMENT OFTHEREQUIREMENTSFORTHEDEGREEOF DOCTOROFPHILOSOPHY UNIVERSITYOFFLORIDA 2001 Tomywife,Hyun-SuLee,andmydaughter,Ye-Bin ACKNOWLEDGMENTS Iwouldfirstliketoacknowledgemysupervisorycommittee.ToDr.Chang-Won Park,myadvisor,Iwouldliketogivethanksandappreciationforhissupportand guidancethroughoutmydoctoralresearch.Iwouldliketoextendmygratitudetomy othercommitteemembers.Dr.SpyrosSvoronos,Dr.RichardB.DickinsonandDr. AnthonyB.Brennanforalltheirinterestinmyworkandhelpfulcommentsand suggestions. IwouldalsoliketoexpressmygratitudetoMr.JuanC.CutieofCyroIndustriesfor providingPMMAsamples,andspecialthanksareduetoMr.GaryScheiffeleofthe EngineeringResearchCenterattheUniversityofFloridaandDr.Jung-SikHwangatthe McMasterUniversityfortheirassistanceinFT-IRandUV-vismeasurements. Inaddition,IgratefullyacknowledgethepartialsupportprovidedbyNanoptics, Inc.,andIwouldliketothankSaehanIndustriesInc.forallowingmetostudyinthe UniversityofFlorida.Iwouldalsoliketogivethankstoallthecolleaguesandfriendsin thechemicalengineeringdepartmentfortheirencouragement,adviceandthegreattimes wehavehadtogether. Iamextremelygratefultomyparentsandparents-in-law.Withouttheirunending loveandsupport,thisworkwouldnothavebeenpossible.Finally,butnotleast,Iwould liketothankmywife,Hyun-SuLee,andmydaughter,Ye-Bin,whosepatience,sacrifice andloveenabledmetocompletethiswork,andmademylifefruitful. Ill 1 TABLEOFCONTENTS Page ACKNOWLEDGEMENTS iii ABSTRACT vi CHAPTERS GENERALINTRODUCTION 1 1 1- 1-1P1l-asticOpticalFiber 1 1-2PrinciplesofFiberOptics 2 1-2-1ClassificationofOpticalfibers 3 2- 1-2-2TotalInternalRefleetion 4 21--2-3ClassificationofRays 6 1-2-4AcceptanceAngleandNumericalAperture 9 1-3ElectromagneticTheoryforOpticalWaveguides 11 1-3-1ElectromagneticWaves 1 1-3-2PhaseShiftsandGuidedModesinaWaveguide 13 1-3-3Dispersion 14 4AdvantagesofGRINFibers 15 1-4-1ChannelCapacity 15 4-2Attenuation 19 2 MODELINGOFGIPOFFABRICATIONPROCESS 23 1Introduction 23 2-2Diffusion-AssistedCoextrusionProcess 24 2-1Modeling 26 2-2-2SimulationResultsandDiscussion 29 2-2-3Multi-layerFibers 35 2-3EstimationofBandwidth 37 2-3-1RayOpticalFormulationofImpulseResponseFunction 37 2-3-2ImpulseResponseCurvesandBandwidths 41 2-3-3WKBApproximation 45 2-4Summary 46 IV 3 FABRICATIONANDCHARACTERIZATIONOFGRINPOF 48 3-1PreparationofGRINFibers 48 3-1-1DPS-DopedGRINFibers 49 3- 3-1-2OilRedEGN-DopedGRINFibers 54 3-2TemperatureDependenceofDiffusivity 58 43--3StabilityofRefractiveIndexProfiles 63 3-4EstimationofBandwidth 66 5Summary 70 4 ANNULUSDIFFUSIONSYSTEM 72 1Introduction 72 4-2Modeling 72 4-3ReliabilityoftheApproximateSolutions 77 4-4Non-NewtonianEffect 79 4-5Experimental 80 4-6ResultsandDiscussion 82 4-7EstimationofBandwidth 86 4-8Summary 89 5 CONCLUSIONS 91 APPENDICES 94 A DERIVATIONOFSERIESSOLUTIONINCYLINDRICALCOORDINATE SYSTEM 94 B DERIVATIONOFSERIESSOLUTIONINCARTESIANCOORDINATE SYSTEM 98 REFERENCES 101 BIOGRAPHICALSKETCH 106 V AbstractofDissertationPresentedtotheGraduateSchool oftheUniversityofFloridainPartialFulfillmentofthe RequirementsfortheDegreeofDoctorofPhilosophy FABRICATIONOFGRADED-INDEX PLASTICOPTICALFIBERBYTHE DIFFUSION-ASSISTEDCOEXTRUSIONMETHOD By In-SungSohn December2001 Chairperson; Chang-WonPark MajorDepartment: ChemiealEngineering Recently,plasticopticalfibers(POFs)havedrawnsignificantattentionashigh- speedtransmissionmediaduetotheiradvantagesoverconventionalglassopticalfibers suchasflexibilityanddurability.Inaddition,Grade-Index(GRIN)POFswithsmoothly varyingrefractiveindicesprovideincreaseddatatransmissionspeedssuitableforthe short-distaneecommunicationssuchaslocalareanetworkingorhomenetworking. Inthisresearch,thediffusion-assistedcoextrusionprocessisintroducedasa methodtofabricateGRINPOFs.Inthisprocess,twoormorepolymeriematerials containingadditivesforrefractiveindexmodificationarefedseparatelyintoa coextrusiondiewhereaconcentriemulti-layerstructureisformed. Subsequently,the diffusionofadditivestakeplacesinadiffusionzonecreatinganon-equilibrium concentrationprofile,hencetherefractiveindexprofile. VI Atheoreticalanalysisforthepredictionoftherefractiveindexprofileobtainableby thisprocessindicatesthatitisdifficulttoobtainanear-parabolicrefractiveindexprofile withthetubularflowdesignunlessaverylargeresidencetimeinthediffusionzoneis provided. However,significantchangesintherefractiveindexprofilecanbeinducedby adoptingamulti-layerapproachandanannulusflowdesign. Furthermore,thebandwidth estimatedbytherayanalysisindicatesthatevenasmallvariationoftherefractiveindex profilecreatedbytheadditivediffusioncanresultinasignificantincreaseinthe bandwidth. Toverifythefindingsfromtheoreticalanalysis,poly(methylmethacrylate)-base GRJNPOFswithdiphenylsulfideanddiphenylsulfoxideasrefractiveindex-modifying dopantswerepreparedandtheeffectsofvariousoperatingconditionssuchasmelt temperatures,flowratesandcore-claddinginterfacepositionswereinvestigated.The dopantconcentrationprofile,thustherefractiveindexprofile,characterizedbyFT-IR spectroscopy,hasbeenshowntobecontrollablebyadjustingthematerialand/orprocess variables. Throughthetheoreticalanalysisandexperimentalverifications,itwasshownthat bandwidthover700MHzata100mdistancecouldbeobtainedbythismethod, suggestingthatthediffusion-assistedcoextrusionprocessisaviablemethodtofabricatea highbandwidthGRJNPOFthatisapplicableforshort-distancecommunications. Vll CHAPTER 1 GENERALINTRODUCTION l-IPlasticOpticalFiber Recently,plasticopticalfibers(POFs)havedrawnsignificantattentionashigh- bandwidthdata-transmissionmediaforlocalareanetworksorhomenetworks.Inspiteof theirhigherattenuationthanglassopticalfibers(GOFs),POFsareperceivedtobemore suitablefortheseapplicationsduetotheirflexibilityanddurability. Theseproperties makeitpossibleforPOFstohavemuchlargercorediametersintheorderof1mm comparedto5-10pmofsingle-modeGOFs.'Sincelargediametermakessplicingof opticalfibersmucheasierandallowsustouselowercostlightsourcesandconnectors, theeconomicadvantageisverysignificant. ItwasinthelatesixtieswhenthefirstPOFwascommerciallydevelopedbyDu Pont,fordisplaypurposes.^Sincethen,developmentsinPOFfabricationhavefocused mainlyonloweringtransmissionlossescausedbyvarioussourcesofintrinsicand extrinsicorigins.Intheearlyseventies,MitsubishiRayonpatentedtheircontinuous spinningprocessforhighpurityacrylics,andthisresultedinthedevelopmentofESKA™ POF,withminimumlossesintheregionof120dB/Kmat567nm.^ ThetheoreticalminimumattenuationofPMMAcorePOFisabout100dB/Kmat thewavelengthof650run,whichrestrictstheirapplicationtodistancesof100matmost. Arecentstudy,however,foundthatabout90%ofalldesktopapplicationsarelocated within80mfromanodecenter,^openingabrightfutureforPOFintheapplicationsof 1 2 short-distancecommunications.ThetransmissionlosslimitofPOFhasbeenfurther loweredto6dB/kmbyadoptingfluorinatedand/ordeuteratedPMMAascorematerial.'* Withtheprogressinthedevelopmentoflow-lossfibersandadvancesinoptical sourcetechnology,applicationsofPOFhavebeenexpandedfromsimplelightdisplaysto opticalsensors,short-distancedatacommunicationsuchaslocalareanetworking(LAN), anddatalinksinautomobilesandaircraft.Inaddition,POFscanhavehighernumerical aperturesthanGOFs,trappingmorelights.Therefore,usingPOFsisalsoadvantageousin imageguideapplicationssuchasendoscopesandindustrialfiberscopes. WhilestandardPOFs,whoserefractiveindexdifferencebetweencoreandcladding isinastepindexprofile,havelimitedbandwidths(lowerthanabout10MHz-Km), gradedindex(GIorGRIN)POFsprovideincreasedsignalbandwidthsduetotheir smoothlyvaryingrefractiveindices.Thus,GRfNPOFsareexpectedtobeusedmore extensivelyashigh-speedopticalsignaltransmissionmediainthenearfuture. ThematerialsforPOFsarepreferablyamorphoushomopolymersthancopolymers tominimizetransmissionlosses.Fiberswithpoly(methylmethacrylate)(PMMA)cores arecurrentlydominantincommercialapplications.Otherpolymerssuchas polycarbonate(PC)andpolysiloxanearealsousedforPOFsfortheirhigherheat resistance.'* 1-2PrinciplesofFiberOptics PropagationoflightinanopticalfiberisdescribedbyMaxwell’sequationssince lightitselfisanelectromagneticwave.However,itiswellknownthatclassicalgeometric opticsprovidesanapproximatedescriptionoflightpropagationwhentherefractiveindex variesonlyslightlyoveradistancecomparabletothewavelengthoflight.Ingeometric 3 optics,lightisconsideredtopropagateinastraightlineinahomogeneousmediuminthe directionnormaltotheequi-phaseplaneofelectromagneticwave.Ithasbeenshownthat opticalwaveguidesmustbemultimodedwith2nRn\6JX»1forgeometricopticstobe valid.^HereRistheradiusofcore,niisthemaximumrefractiveindexofcorematerial, 6cisthecritiealangleandXisthefree-spacewavelengthofthelight. Inthisresearch, geometricopticsisadoptedfortheestimationofbandwidthcharacteristicsofoptical fibersforitssimplicityalthoughseveralelectromagneticconceptsareintroducedfor morethroughunderstandingoftheunderlyingprinciplesoffiberoptics. 1-2-1ClassificationofOpticalfibers Opticalfibersareclassifiedintotwomaincategories.Oneisthestepindex(SI) fiberandtheotherthegradedindex(GIorGRIN)fiber.TheSIfibersconsistofthecore withhigherrefractiveindexmaterialsandcladdingwithlowerrefractiveindexmaterials. Therefractiveindexprofileforthistypeoffibermakesastepchangeatthecore-cladding interfaceasindicatedinFigure1-la.Ontheotherhand,GRINfibersdonothavea constantindexinthecore,butasmoothlyvaryingindexprofileoverthefiberradiuswith amaximumvalueof attheaxisandaconstantvalue«2beyondthecoreradiusRinthe cladding(Figure1-lb). Graded-indexfibersexhibitfarlessintermodaldispersionthanstepindexfibersdue totheirrefractiveindexprofile.AlthoughmanydifferentmodesareexcitedintheGRIN fiber,thedifferentgroupvelocitiesofthemodestendtobenormalizedbytheindex grading.Ingeometricopticalperspective,theraystravelingclosetothefiberaxishave shorterpathscomparedwithraysthattravelintheouterregionofthecore.However,the nearaxialraysaretransmittedthrougharegionofhigherrefractiveindex,andhencethey

ebook img

Fabrication of graded-index plastic optical fiber by the diffusion-assisted coextrusion method PDF

115 Pages·2001·4.2 MB·English
by  Sohn, In-Sung, 1965-
#americana #univ_florida_smathers #UFRDS
Save to my drive
Quick download
Download

Download Fabrication of graded-index plastic optical fiber by the diffusion-assisted coextrusion method PDF Free - Full Version

by Sohn, In-Sung, 1965-| 2001| 115 pages| 4.2| English

Download Fabrication of graded-index plastic optical fiber by the diffusion-assisted coextrusion method by Sohn, In-Sung, 1965- in PDF format completely FREE. No registration required, no payment needed. Get instant access to this valuable resource on PDFdrive.to!

Free Download PDF

About Fabrication of graded-index plastic optical fiber by the diffusion-assisted coextrusion method

No description available for this book.

Detailed Information

Author:Sohn, In-Sung, 1965-
Publication Year:2001
Pages:115
Language:English
File Size:4.2
Format:PDF
Price:FREE
Download Free PDF

Safe & Secure Download - No registration required

Why Choose PDFdrive for Your Free Fabrication of graded-index plastic optical fiber by the diffusion-assisted coextrusion method Download?

  • 100% Free: No hidden fees or subscriptions required for one book every day.
  • No Registration: Immediate access is available without creating accounts for one book every day.
  • Safe and Secure: Clean downloads without malware or viruses
  • Multiple Formats: PDF, MOBI, Mpub,... optimized for all devices
  • Educational Resource: Supporting knowledge sharing and learning

Free Books Similar to Fabrication of graded-index plastic optical fiber by the diffusion-assisted coextrusion method

Frequently Asked Questions

Is it really free to download Fabrication of graded-index plastic optical fiber by the diffusion-assisted coextrusion method PDF?

Yes, on https://PDFdrive.to you can download Fabrication of graded-index plastic optical fiber by the diffusion-assisted coextrusion method by Sohn, In-Sung, 1965- completely free. We don't require any payment, subscription, or registration to access this PDF file. For 3 books every day.

How can I read Fabrication of graded-index plastic optical fiber by the diffusion-assisted coextrusion method on my mobile device?

After downloading Fabrication of graded-index plastic optical fiber by the diffusion-assisted coextrusion method PDF, you can open it with any PDF reader app on your phone or tablet. We recommend using Adobe Acrobat Reader, Apple Books, or Google Play Books for the best reading experience.

Is this the full version of Fabrication of graded-index plastic optical fiber by the diffusion-assisted coextrusion method?

Yes, this is the complete PDF version of Fabrication of graded-index plastic optical fiber by the diffusion-assisted coextrusion method by Sohn, In-Sung, 1965-. You will be able to read the entire content as in the printed version without missing any pages.

Is it legal to download Fabrication of graded-index plastic optical fiber by the diffusion-assisted coextrusion method PDF for free?

https://PDFdrive.to provides links to free educational resources available online. We do not store any files on our servers. Please be aware of copyright laws in your country before downloading.

The materials shared are intended for research, educational, and personal use in accordance with fair use principles.

We use cookies

We use cookies to ensure you get the best browsing experience on our website. By clicking "Accept Cookies", you agree that we can store cookies on your device in accordance with our Terms and Privacy.