Study of Photons Orbital Angular Momentum for Optical Communications

107 Pages·2015·39.78 MB·English

Study of Photons Orbital Angular Momentum for Optical
Communications
André Madeira Bastos da Cunha
Thesis to obtain the Master of Science Degree in
Engineering Physics
Supervisors: Professor Paulo Sérgio de Brito André
Professor Gonçalo Nuno Marmelo Foito Figueira
Examination Committee
Chairperson: Professor Luís Paulo da Mota Capitão Lemos Alves
Supervisor: Professor Gonçalo Nuno Marmelo Foito Figueira
Members of the Committee: Professor João Alberto dos Santos Mendanha Dias
Professor Armando Humberto Moreira Nolasco Pinto
November 2015
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Acknowledgments
I’dliketostartbythankingmyparentsJuvenalandLídia,whohaveencouragedandsupportedmethrough-
outallmylifeandmywifeJoanawhostoodbymysideandprovidedmegreatsupportduringthisjourney.
Furthermore, this work would not have been possible without the openness, encouragement and great
supportprovidedbybothProfessorsPauloAndréandGonçaloFigueira. Iwouldliketoremarkthatonlythe
promptnessandopennessofbothtointer-collaborationandnewideasprovidedthenecessarybasisforthe
bridgingbetweenphysicsandopticalcommunicationsbyallowingthiswork,whichfocusonanalbeitexotic,
butrathertrendyandinnovativesubject.
Andofcourse,ImustalsothankthesupportofInstitutodeTelecomunicações(IT)andFundaçãoparaa
Ciência e Tecnologia (FCT) who provided equipment and financial support to enable this work, the Group
of Lasers and Plasmas (GOLP), Instituto de Plasmas e Fusão Nuclear (IPFN) who provided the necessary
installations at Laboratório de Lasers Intensos (L2I) for our setup and provided multiple optical equipment
butalsoascientificenvironmentofhighlycapableandhelpfulpeoplewhoprovidedsupportthroughoutthis
work.
Finally,Iwanttoacknowledgemycolleaguesandfriends,whowerethereformewhenIneededthem,es-
peciallyJoãoRomãofortheprolificdiscussionsandinsightsandPedroMiguelCruzandManuelNascimento
for their patience and companionship but also colleagues Alexandra Gouveia and Tiago Guerra Marques
giventheworkwedevelopedtogetheryearsago.
Fortheonesunmentioned,awordofapologybuttheassurancethatIholdaspecialplaceforyouinmy
heart.
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Resumo
Acapacidadedetráfegodedadosnainternetestárapidamenteaatingiroslimitesimpostospelosefeitos
nãolinearesdafibraóptica,tendoquaseesgotadoosgrausdeliberdadedisponíveisnecessáriosparamul-
tiplexar ortogonalmente o tráfego de dados. Desta forma, resultados recentes sugerem que o momento
angular orbital (MAO) dos fotões talvez possa ser usado como grau de liberdade adicional para este fim,
providenciandoemteoria,umnúmeropotencialmenteilimitadodeestadosortogonais,apresentando-seas-
simcomoumpossívelsaltodegiganteparaasredesdetelecomunicaçõesdofuturo.
Palavras Chave
MomentoAngularOrbital(MAO),TelecomunicaçõesÓpticas,ÓpticaemEspaçoLivre,Laguerre-Gaussiano
(LG),Óptica,ModuladorEspacialdeLuz(MEL)
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Abstract
Theinternet datatraffic capacity israpidly reaching thelimits imposedby optical fibernonlinear effects,
havingalmostexhaustedtheavailabledegreesoffreedomneededtoorthogonallymultiplexdata. Therefore
the need urges to develop new methods in order to avoid the upcoming capacity crunch using classical
communications channels. In this regard, recent results have suggested that the use of the orbital angular
momentum (OAM) of photons as an additional degree of freedom is potentially unlimited in the number of
achievable orthogonal states, therefore presenting itself as a possible major technological leap for future
communicationnetworks.
Keywords
OrbitalAngularMomentum(OAM),OpticalCommunications,FreeSpaceOptics(FSO),Laguerre-Gaussian
(LG),Optics,SpatialLightModulator(SLM)
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