Optical Networks
Mostrando 13-24 de 178 artigos, teses e dissertações.
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13. Estimation Uncertainties in the Optical Signal-to-Noise Ratio Network Optimization
In this work, we investigate the effects of estimation uncertainties in the optimization of the optical signal-to-noise ratio (OSNR) at the wavelength division multiplexing (WDM) optical networks. The OSNR optimization increases the network throughput and energy efficiency and it enables to minimize the number of retransmissions by higher layers. The OSNR op
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2016-03
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14. Experimental-based subsystem models for simulation of heterogeneous optical networks
This work presents and analyzes experimental-based subsystem models for Erbium doped fiber amplifiers (EDFAs) and wavelength selective switches (WSSs) under operation in a metropolitan optical network testbed. Firstly, the performance of the EDFAs and two gain control types are analyzed in a heterogeneous experimental setup with lightpaths modulated at 10G/1
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2014-12
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15. Wavelength assignment using a hybrid evolutionary computation to reduce cross-phase modulation
In this paper, we propose a hybrid methodology based on Graph-Coloring and Genetic Algorithm (GA) to solve the Wavelength Assignment (WA) problem in optical networks, impaired by physical layer effects. Our proposal was developed for a static scenario where the physical topology and traffic matrix are known a priori. First, we used fixed shortest-path routin
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2014-06
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16. Optimal design of an IP/MPLS over DWDM network
Different approaches for deploying resilient optical networks of low cost constitute a traditional group of NP-Hard problems that have been widely studied. Most of them are based on the construction of low cost networks that fulfill connectivity constraints. However, recent trends to virtualize optical networks over the legacy fiber infrastructure, modified
Pesqui. Oper.. Publicado em: 2014-04
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17. Hybrid distributed Raman/EDFA amplifier with hybrid automatic gain control for reconfigurable WDM optical networks
Nowadays, optical amplifiers designs are induced by new requirements generated by optical networks. The introduction of WDM reconfigurable networks with increasing rate from 10-40 Gb/s to 100 Gb/s and beyond, demand new optical amplifiers development with improved gain spectral flatness and noise figure for all operational range of input powers and set-point
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-12
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18. Comparing OSNR based policies for an adaptive-alternative IA-RWA algorithm applied to all-optical networks
We propose two policies to select the route for an adaptive-alternative routing algorithm for all-optical networks. We use the NrPSR to find the Nr routes with lower cost for a given source-destination pair according to a cost function expanded in a power series (PSR) in which the coefficients are determined by a Particle Swarm Optimizer (PSO). The selected
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-12
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19. 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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20. Particle swarm optimization in WDM/OCDM networks with physical impairments
In this paper, optimization procedures based on particle swarm optimization (PSO) are investigated, aiming to efficiently solve the optimal resource allocation for signal-to-noise plus interference ratio (SNIR) optimization of optical code paths (OCPs) from wavelength division multiplexing/optical code division multiplexing (WDM/OCDM) considering imperfectio
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-12
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21. Optical cryptography through analog control of amplitude and delay of spectral slices: anlysis for NRZ and DQPSK signals. / Criptografia Ãptica mediante controle analÃgico da amplitude e do atraso de fatias espectrais: anÃlise para sinais NRZ e DQPSK.
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, a
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 23/11/2012
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22. Quantificação óptica de carboidratos e etanol em mosto cervejeiro / Optical quantification of carbohidrates ; ethanol in beer wort
Neste estudo realizamos uma prova de conceito através da combinação de três técnicas com a finalidade de monitorar a mosturação e fermentação da cerveja durante o processo de fabricação. O princípio deste trabalho é baseado em uma análise espectral, utilizando um equipamento de absorção na região do infravermelho médio por transformada de F
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 08/10/2012
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23. Estudos de sistemas OFDM para comunicações ópticas / Studies OFDM systems for optical communications
The development of digital modulation formats in optical communications systems is considered to be a promising way to increase the spectral efficiency and to combat the effects of signal degradation in optical fiber without changing the infrastructure already deployed. In this context, the technique called OFDM (orthogonal frequency division multiplexing) e
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 03/10/2012
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24. 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