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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Criptografia ?ptica mediante controle anal?gico da amplitude e do atraso de fatias espectrais: an?lise para sinais NRZ e DQPSK / Optical cryptography through analog control of amplitude and delay of spectral slices: anlysis for NRZ and DQPSK signals

Fossaluzza Junior, Luiz Antonio 23 November 2012 (has links)
Made available in DSpace on 2016-04-04T18:31:33Z (GMT). No. of bitstreams: 1 Luiz Antonio Fossaluzza junior.pdf: 4580835 bytes, checksum: 4fdd68a1c6733e08c016db3e5dd34d0b (MD5) Previous issue date: 2012-11-23 / This work investigates a technique to encrypt the optical signal for Transparent Optical Network, TON, in order to safeguard the confidentiality and guarantee the security of informations that are transmitted through the Telecommunications Network. The technique is assessed on the physical layer of the reference model for open systems interconnection, OSI, and consists of slicing spectrally optical signal and to apply various attenuations and delays to each of the slices spectral considered. These slices are multiplexed and the resulting signal, which will be propagated by an optical network transparent, it will be ideally unintelligible to eavesdropper who try to steals it. At this point is possible to evaluate the quality of the encryption used by measuring the output of the encoder the bit error rate, BER, the encrypted signal, BERC. In principle, as highest BERC,it will be lowest the probability of an eavesdropper decode the signal. To get to your destination, the signal is received in the decoder circuit, which has the same physical structure of the circuit which encoded the original signal. The application of the factors of attenuation and delay in this distorted signal is adjusted for the reconstruction of optical signal generated by the transmitter. On the output of decoder, performs the measurement of BER of signal decoded, the BERD. Ideally, BERD must be the lowest possible. For technique evaluation, it was simulated, with the version 8.7 of the software VPITransmissionMaker, of company VPIPhotonics Inc, the operation of the devices of cryptography, propagation and the elements of decoded signal. All simulations considered that the spectral slicing was carried out by means of filters with ideal profile. The results indicates that the BERC may reach up to 42% and 24%, to encrypted signals with modulation on-off Keying non return to zero (NRZ-OOK) and differential quadrature phase shift keying (DQPSK) respectively, and that both are free of errors (BERD< 10-15 for the signal NRZ-OOK and BERD< 10-6 for DQPSK modulation) when decoded. / Este trabalho aborda uma t?cnica para criptografar o sinal ?ptico em redes ?pticas transparentes (Transparent Optical Network, TON), de modo a salvaguardar o sigilo e garantir a seguran?a das informa??es que s?o transmitidas atrav?s da Rede de Telecomunica??es. A t?cnica avaliada ? relativa ? camada f?sica do modelo de refer?ncia para interconex?o de sistemas abertos (open systems interconnection, OSI) e consiste em dividir espectralmente um sinal ?ptico e em aplicar diferentes atenua??es e atrasos a cada uma das fatias espectrais consideradas. A seguir essas fatias s?o multiplexadas e o sinal resultante, que ser? propagado por uma rede ?ptica transparente, estar? idealmente inintelig?vel para intrusos que tentem furt?-lo. Nesse ponto ? poss?vel avaliar a qualidade da criptografia utilizada, medindo-se na sa?da do codificador a taxa de erro de bit (bit error rate, BER) do sinal criptografado, BERC. Em princ?pio, quanto maior BERC, menor a probabilidade de um intruso decodificar o sinal. Ao chegar ao seu destino, o sinal ? recebido no circuito decodificador, que possui a mesma estrutura f?sica do circuito que codificou o sinal original. A aplica??o dos fatores de atenua??o e atraso neste sinal distorcido ? ajustada para a reconstru??o do sinal ?ptico gerado pelo transmissor. Na sa?da do decodificador, efetua-se a medi??o da BER do sinal decodificado, BERD. Idealmente, BERD deve ser a menor poss?vel. Para avalia??o da t?cnica, simulou-se, com a vers?o 8.7 do software VPITransmissionMaker, da empresa VPIPhotonics Inc, a opera??o dos dispositivos de criptografia, da propaga??o e dos elementos de decriptografia do sinal. Todas as simula??es consideraram que o fatiamento espectral foi realizado por meio de filtros com perfil ideal. Os resultados indicam que a BERC pode atingir at? 42% e 24%, para sinais codificados com modula??o n?o retorno ao zero com chaveamento on-off (non return to zero on-off keying, NRZ-OOK) e por deslocamento de fase diferencial em quadratura (differential quadrature phase shift keying, DQPSK) respectivamente, e que ambos n?o apresentam erros (BERD< 10-15 para o sinal NRZ-OOK e BERD< 10-6 para a modula??o DQPSK) quando decodificados.
2

Avalia??o de dispositivos de fot?nica de sil?cio para o projeto de filtros ?pticos de banda estreita / Evaluation of silicon photonics devices for the design of narrow-bandwidth optical filters

Martins, Claudinei 30 June 2015 (has links)
Made available in DSpace on 2016-04-04T18:31:43Z (GMT). No. of bitstreams: 1 CLAUDINEI MARTINS.pdf: 2135890 bytes, checksum: 419e34d778fa576dcea52630975b8c78 (MD5) Previous issue date: 2015-06-30 / Pontif?cia Universidade Cat?lica de Campinas / The intensive use of high-density data applications has driven the relentless pursuit of networks capable to provide high traffic capacity. The transparent optical networks plays an important role in the telecommunications infrastructure core, being able to meet these demands. New technologies to terabits per second networks have created a new stage of development for optical communications. New optical components that allows signal process in addition to just transportation, are needed. The scope of these networks extends from the core of the infrastructure to the end user, reaching the last mile, and recently also end devices such as computers, televisions and Internet. In this context, Silicon Photonics gained momentum in the last decade, as an alternative to the need to take the processing of optical signals to levels similar to those already made by semiconductor technology, in processing electrical signals. In our work, we studied systematically using simulations, ring resonators structure in Silicon Photonics, as technology to build miniaturized devices capable of handling optical signals. In particular, we investigated optical band-pass filter design narrowed than such filters used to the separation channel in wavelength division multiplexing systems, for application in various areas of optical networks such as radio over fiber, multiplexers, all optical encoders and modulators. In this work uses ring resonators structure for construction of these high order filters with reduced size, with a substrate of some micrometers area. Such filters could be built into microchips and integrated with other optical and optical-electronic components, resulting in more complex systems, in the near future. The main result was an optical band-pass filter with 8.6 GHz bandwidth based on asymmetric ring resonators with two sets of three rings, with following radii 5 ?m, 2.5 ?m and 5 ?m using a substrate area of 1840 ?m2 or, 57 ?m x 120 ?m. / O uso intensivo de aplica??es de alta densidade de dados tem impulsionado a busca constante por redes capazes de prover elevada capacidade de tr?fego. As redes ?pticas transparentes s?o capazes de atender a estas demandas e cumprem um papel relevante no n?cleo da infraestrutura de telecomunica??es. As novas tecnologias para redes de terabits por segundo criaram uma nova etapa do desenvolvimento das comunica??es ?pticas e novos componentes com capacidade n?o s? de transporte, mas tamb?m de processamento do sinal ?ptico tornaram-se necess?rios. A abrang?ncia destas redes estende-se do n?cleo da infraestrutura at? o usu?rio final, chegando ? ?ltima milha e, mais recentemente, tamb?m aos dispositivos finais, tais como computadores, televisores e Internet. Neste contexto, a Fot?nica de Sil?cio ganhou impulso, na ?ltima d?cada, como uma alternativa ? necessidade de levar o processamento dos sinais ?pticos a n?veis semelhantes aos j? realizados pela tecnologia de semicondutores no processamento de sinais el?tricos. Em nosso trabalho, pesquisamos de forma sistem?tica, utilizando simula??es, para o projeto de filtros com an?is ressoantes, constru?dos em Fot?nica de Sil?cio, para desenvolvimento de dispositivos miniaturizados capazes de tratar sinais ?pticos. Em particular, investigou-se o projeto de filtros ?pticos passa-faixa, de banda inferior ? utilizada, para separa??o de canais em sistemas de multiplexa??o por divis?o de comprimento de onda, para aplica??o em diversas ?reas das redes ?pticas, tais como r?dio sobre fibra, multiplexadores, moduladores e codificadores totalmente ?pticos. Neste trabalho, utiliza-se estrutura de an?is ressonantes para constru??o destes filtros, de ordem elevada e de tamanho reduzido, em um substrato de alguns micr?metros de ?rea. Tais filtros poder?o ser constru?dos em microchips e integrados com outros componentes ?pticos e ?ptico-eletr?nicos, dando origem a sistemas mais complexos no futuro pr?ximo. O principal resultado obtido foi um filtro ?ptico passa banda com 8,6 GHz de largura de banda, baseado em an?is ressoantes assim?tricos, composto de duas estruturas de tr?s an?is de raios 5 ?m, 2,5 ?m e 5 ?m, utilizando uma ?rea de substrato de 6840 ?m2 ou 57 ?m x 120 ?m.

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