Optical Network
Mostrando 13-24 de 148 artigos, teses e dissertações.
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13. 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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14. Enhancement of Optical Absorption, Photoluminescence and Raman Transitions in Bi2O3-GeO2 Glasses with Embedded Silver Nanoparticles
The influence of silver nanoparticles (Ag-NPs) on the optical properties of Bi2O3-GeO2 glasses was investigated aiming the characterization of their potential for applications in photonic devices. The samples were prepared by the melt-quenching technique starting from high purity oxides (GeO2, Bi2O3 and AgNO3). Heat-treatment during different times was perfo
J. Braz. Chem. Soc.. Publicado em: 2015-12
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15. 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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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. Optimal traffic Re-Grooming model for heterogeneous carrier ethernet services over WDM Optical Network
This paper proposes three novel integer linear programming (ILP) formulations, where the first model deals with the Grooming, Routing, Wavelength Assignment, and Carrier Ethernet Interface Allocation Problem (GRWA-I); the second to Traffic Re-Grooming Problem (TRGP) to accommodate demand changes in a GRWA-I network scenarios; and the third to Traffic Re-Groo
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-12
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18. 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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19. 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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20. 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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21. Estudo experimental do tempo de recuperação de falhas em comutadores de caminhos óticos
A contribuição desta dissertação consiste na integração de um comutador de caminhos óticos (Optical Cross Connect (OXC)) em um sistema de enlace ótico ponto-a-ponto. Com essa integração, é possível oferecer a camada ótica os serviços de aprovisionamento dinâmico de caminhos óticos, proteção ou restauração automática de caminhos óticos,
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 27/01/2012
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22. OPTICAL NETWORK TRANSFORMATION ON ACCESS AND METROPOLITAN BACKBONE RING: TECHNOLOGICAL AND ECONOMICAL ALTERNATIVES AND NEW SERVICES / A TRANSFORMAÇÃO DAS REDES ÓPTICAS NO ACESSO E NO ANEL BACKBONE METROPOLITANO: ALTERNATIVAS TECNOLÓGICAS, ECONÔMICAS E NOVOS SERVIÇOS
A presente dissertação tem como objetivo avaliar as mudanças que estão ocorrendo nas arquiteturas das redes ópticas dos operadores de telecomunicações para adequarem-se aos novos serviços oferecidos aos usuários. Esses serviços demandam cada vez mais flexibilidade, confiabilidade e capacidade de todos os níveis das redes ópticas, desde o acesso a
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 24/01/2012
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23. 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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24. Increasing energy efficiency in OCDMA network via distributed power control
In this work, we investigate the utilization of transmission power control as mechanism to increase the energy efficiency in optical code division multiplexing access (OCDMA) networks. We have modeled the energy efficiency considering the optical fiber transmission and network infrastructure as encoders, decoders and star coupler. In the analyzed scenario, t
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2012-06