Optical Links
Mostrando 1-12 de 32 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. EDFA Design and Analysis for WDM Optical Systems Based on Modal Multiplexing
Abstract Modal multiplexing (MDM) is a core technology to allow a capacity increase in modern optical systems. However, in MDM links, the amplified WDM signal suffers not only from lack of spectral gain equalization but also from unequal modal gain. The proper design of the MDM-EDFA is crucial to provide modal gain equalization and to overcome those impairme
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-03
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3. An Analytical Solution for Fiber Optic Links with Photonic-Assisted Millimeter Wave Upconversion Due to MZM Nonlinearities
Abstract Photonic-assisted technique employed in the generation of stable and high-purity signals in the millimeter wave band has been investigated using dual-parallel Mach-Zehnder modulator. Indeed, this type of generation performs a high order RF multiplier, whose operation principle steams out from the nonlinear characteristic of the external modulators.
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-03
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4. A Multilayer Approach for Optical Network Planning
With the increase in demand to Backbone networks, one became fundamental the application of new telecommunication technologies for efficient use of devices and optical links, such as xPSK modulations with dual polarization, dispersion compensating fibers, coherent detection and digital processing signals. Thus, network planning using analytical models have b
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2016-03
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5. Degradação de sinais com modulação NRZ-DQPSK e 16-QAM em enlaces ponto a ponto com amplificadores ópticos a semicondutor = : NRZ-DQPSK and 16-QAM signal degradation in fiber links with semiconductor optical amplifiers / NRZ-DQPSK and 16-QAM signal degradation in fiber links with semiconductor optical amplifiers
Modulações ópticas avançadas como DQPSK e QAM tem sido escolhidas por serem formatos multiniveis (dois bits ou mais por símbolo), aumentando a eficiência espectral de sistemas ópticos. Entretanto, o amplificador óptico a semicondutor (SOA) indicado principalmente para aplicações de media distancia (da ordem de 20 km), pode degradar o sinal DQPSK e
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 26/07/2012
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6. The effect of hot multistage drawing on molecular structure and optical properties of polyethylene terephthalate fibers
In this work, mechanical and structural parameters related to the optical properties of polyethylene terephthalate (PET) fibers drawn at hot multistage have been investigated. The changes in optical parameters upon changing draw ratio are used to obtain the mechanical orientation factors
and , various orientation functions f2(θ), f4 Materials Research. Publicado em: 17/07/2012
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7. AnÃlise experimental da degradaÃÃo imposta por sistemas Ãpticos a aplicaÃÃes IP / Experimental analysis of the degradation imposed by optical systems on IP
The objective of this work is to experimentally evaluate how physical impairments on the network can affect the performance of IP applications. Especially This work encompasses the analysis of the cross-layer effect caused by all-optical wavelength converters in the video signal. For this purpose, it was evaluated the packet error rate degradationcaused by p
Publicado em: 2010
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8. A unified framework for shared protection schemes in optical mesh network
Embora as vantagens dos p-ciclos e FIPP p-ciclos estejam bem estabelecidas, não existe uma análise sistemática de quanta largura de banda eles consomem em comparação aos mecanismos clássicos de proteção compartilhada por caminhos e por links. Foi observado recentemente que a enumeração de um enorme número de ciclos não é necessariamente uma gara
Pesquisa Operacional. Publicado em: 2009-12
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9. Análise experimental da aplicação da tecnologia de rádio sobre fibra em redes IEEE 802.15.4 / Analysis of applying the technology of radio-overfiber networks in IEEE 802.15.4.
This work presents an experimental investigation on the implementation of wireless sensor networks (IEEE 802.15.4) over fiber optics. Such investigation was performed with the utilization of IEEE 802.15.4 transceivers, an optical fiber infrastructure inside a field-trial network, called KyaTera Network, and directly modulated lasers and photodiodes designed
Publicado em: 2009
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10. Study of special modulation formats for optical communication / Estudo de formatos especiais na modulação digital para comunicações ópticas
This MSc thesis investigates optical modulation formats as an alternative to the use of the traditional intensity binary format NRZ (Non-return-to-zero). Those formats, classified as advanced, represent one of the key technologies aimed to enable the high data volume and broadband, demanded by the present telecommunication market, with cost reduction of tran
Publicado em: 2009
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11. Effect of the artificial accelerated aging on optical properties and conversion degree of expired composites / Efeito do envelhecimento artificial acelerado sobre as propriedades opticas e a conversão monomerica de compositos vencidos
Presently, the excellent aesthetic results obtained with composites require the dentist to use several composite resin hues to make a restoration. Nonetheless, to do this, little material is used, and many times, due to this low usage, the composite reaches its expiration date with material remaining in the packaging. The purpose of this study was to evaluat
Publicado em: 2009
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12. AVALIAÇÃO EXPERIMENTAL DOS EFEITOS DE CINTILAÇÃO NO CANAL ÓPTICO NO ESPAÇO LIVRE EM 780 NM, 1550 NM E 9100 NM / EXPERIMENTAL EVALUATION OF SCINTILLATION EFFECTS IN FREE SPACE OPTICAL CHANNEL IN 780 NM, 1550 NM AND 9100 NM
Optical laser communication in free space is an area that has been attracting increasing interest in the last years, due to its possible capacity to resolve the problem of information diffusion, giving higher capacity access to users. Wireless optical systems offer speedy installation and initialization procedures and system flexibility, with the equivalent
Publicado em: 2008