Optical Communication
Mostrando 1-12 de 84 artigos, teses e dissertações.
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1. MGF Methods for Fixed and Gain Saturated Optically Preamplified FSO Links Impaired by Misalignments and Atmospheric Turbulence
Abstract The Gaussian approximation is commonly used to evaluate the performance of free space optical communication systems. However, other performance evaluation methods such as the saddle point approximation, Chernoff bound and the modified Chernoff bound have also been used. This paper investigates the performance of fixed and gain saturated optically pr
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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2. Interplay between Near-Field Properties and Au Nanorod Cluster Structure: Extending Hot Spots for Surface-Enhanced Raman Scattering
Materials science has observed a continuous increase in the use of metal nanoparticles in a wide range of studies, from fundamental physics to technological applications such as photocatalysis and optical communication devices. This broad scope has the same fundamental origin, the localized surface plasmons, whose excitation leads to strong light confinement
J. Braz. Chem. Soc.. Publicado em: 24/10/2019
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3. Biological modulation of corneal epithelial wound healing
RESUMO A transparência e a manutenção da integridade epitelial da córnea são essenciais para suas propriedades ópticas e, para preservar tais características, o epitélio sofre renovação contínua. Essa renovação depende do controle da proliferação e diferenciação celular mediadas por fatores mitogênicos responsáveis pelo aumento das mitoses
Arq. Bras. Oftalmol.. Publicado em: 2019-02
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4. Optically controlled reconfigurable antenna for 5G future broadband cellular communication networks
Abstract This paper presents an optically controlled reconfigurable antenna for millimetre-wave frequency range. Silicon switches are used to control the optical reconfiguration, modifying the frequency response and radiation pattern of the antenna design. Therefore, the system can switch between the lightly licensed 28 GHz and 38 GHz frequency bands, useful
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-03
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5. Link Optimization and Performance Analysis of a 40 Gbps DQPSK Modulated Ultra DWDM System with 32 Orthogonally Polarized channels
Abstract The demand for higher speed at a lesser transmission cost per bit resulted in growth of optical networks with improved spectral efficiency even at narrower channel spacing. Incorporation of multilevel modulation formats in DWDM system led to the exploration of the 25 GHz channel grid, popularly known as Ultra Dense Wavelength Division Multiplexed (U
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2016-12
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6. Artificial Immune Network Design of Optical Multiplexers/Demultiplexers
Abstract An efficient design approach of directional couplers based multiplexers/demultiplexers for optical communication applications, by using an adapted artificial immune network algorithm for optimization (opt-AiNet), is presented and validated by using the beam propagation method. Two key multiplexers/demultiplexers based on planar waveguides and optica
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2015-12
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7. From Lighting to Photoprotection: Fundamentals and Applications of Rare Earth Materials
Light and rare earths (RE) have a long lived relationship that dates from the discoveries of these elements in the nineteenth century. Since then, the increasing comprehension of their spectroscopic properties conducted to a wide and alluring literature about light absorption and emission by this particular and fascinating group. For more than 50 years, RE-c
J. Braz. Chem. Soc.. Publicado em: 2015-12
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8. All-optical cryptography through spectral amplitude and delay encoding
All-optical data encryption is a promising technology that could lead communication systems to an unprecedented degree of security. In this paper we use computer simulations to systematically investigate a new all-optical cryptography technique that is bit-rate independent and transparent to modulation formats. Encryption encompasses signal spectral slicing
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-12
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9. Sistemas CDMA ópticos coerentes baseados em codificação de fase espectral / Coherent optical CDMA systems based on spectral phase coding
In this work we perform a comprehensive analysis of a spectral phase-encoded time spreading optical code division multiple access (SPECTS-OCDMA) system. Despite being a numerical study, efforts were concentrated on the investigation of more realistic scenarios using as much information as possible from implemented test-beds in laboratories. In this context,
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 11/12/2012
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10. Proposal of a new approach for BER evaluation of multirate, multiservice OCDMA systems / Proposta de uma nova abordagem para o cálculo da BER de sistemas OCDMA de múltiplas taxas e multiserviços
The continuous evolution of the optical communication technology in the last few years has allowed the growing users demand for higher bandwidth to be satisfactorily attended. This new demand is mainly attributed to the growing popularity of bandwidth-intensive networking applications, such as Internet protocol television (IPTV), high-definition television (
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 24/08/2012
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11. Projeto e desenvolvimento de um sistema de medição sem contato aplicado ao processo de torneamento / DESIGN AND DEVELOPMENT OF A NON CONTACT MEASUREMENT SYSTEM APPLIED THE PROCESS OF TURNING
This work presents a non contact measurement techniques study on the manufacturing process and the design and development of a non contact measurement system for inspection of diameters of parts during the machining process on the lathe. Amongst the techniques are showed technologies which are based on physical principles of optical, pneumatic, electric or u
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 14/12/2011
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12. Transporte TDM em redes GPON / TDM transport in GPON networks
Neste trabalho analisamos e propomos a utilização de TDM (Time Division Multiplexing) nativo canalizado/estruturado em redes PON (Passive Optical Network) com padrão GPON (Gigabit Passive Optical Network), com ênfase na estrutura de transmissão do legado das redes de telefonia. O objetivo principal é obter um aumento na eficiência de banda transmitida
Publicado em: 2011