Margarida Facao

Margarida Facao

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Research Focus & Metrics

Academic Career Length

31Years (1996-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 May 2005 in Fiber and Integrated Optics
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Journal Article
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Mário FerreiraMário Ferreira
Mário Ferreira
MFMargarida Facao
Margarida Facao
SLSofia C. V. Latas
Sofia C. V. Latas
MSM. H. Sousa
M. H. Sousa
A brief history of attempts to use solitons for optical fiber communications and of the technical developments toward making soliton transmission practical is reviewed. The main problems affecting long-distance soliton transmission, as well as techniques to solve them, are described. Recent developments concerning the use of dispersion management and some of the remarkable properties of dispersion managed solitons are also discussed.

19 April 2011 in Applied Physics B
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SLSofia C. V. Latas
Sofia C. V. Latas
Mário FerreiraMário Ferreira
Mário Ferreira
MFMargarida Facao
Margarida Facao

18 July 2003 in Physical Review E
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MFMargarida Facao
Margarida Facao
DPD. F. Parker
D. F. Parker
Normal mode stability of both rectilinear and self-bending photorefractive screening solitons is considered. In each case, the Evans function procedure is used to investigate stability and to search for internal modes. For the rectilinear case, a standard Evans function procedure is applied. However, in the self-bending case the asymptotic form of the eigenvalue problem is a system of Airy equations, instead of the usual system of constant coefficient differential equations. To overcome this difference, a modified version of the Evans function method, using Airy functions rather than exponentials, is implemented and applied. The results confirm stability and give an internal mode pattern in good agreement with full numerical integration.

22 November 2010 in IEEE Sensors Journal
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Journal Article
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ARAna Maria Rocha
Ana Maria Rocha
Paulo AntunesPaulo Antunes
Paulo Antunes
Maria de Fátima DominguesMaria de Fátima Domingues
Maria de Fátima Domingues
MFMargarida Facao
Margarida Facao
PAPaulo Andre
Paulo Andre
In this paper, we propose a new technique to detect the presence of the fiber fuse effect propagation. The implemented technique consists on the utilization of two fiber Bragg gratings (FBGs) as temperature sensors in order to detect the transit of the thermal wave associated with the fuse effect. The developed technique was used to determine the fuse propagation velocity in single mode fibers as function of the injected optical pump power, yielding a direct proportionality constant value of 0.106 ± 0.028 ms-1W-1.

30 September 2010 in Optics Express
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MCM. I. Carvalho
M. I. Carvalho
MFMargarida Facao
Margarida Facao
New types of finite energy Airy beams are proposed. We consider two different types of beams, namely, beams that are obtained as blocked and exponentially attenuated versions of Airy functions Ai and Bi, and beams of finite width but having the Airy functions typical phase. All of them show very interesting properties, such as parabolic trajectories for longer propagation distances, profile evolution exhibiting less diffraction, or better definiteness of the main peak, when compared with other finite energy Airy beams studied before.

26 September 2019 in Physical Review E
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MCM. I. Carvalho
M. I. Carvalho
MFMargarida Facao
Margarida Facao
We found stable soliton solutions for two generalizations of the cubic complex Ginzburg-Landau equation, namely, one that includes the term that, in optics, represents a delayed response of the nonlinear gain and the other including the self-steepening term, also in the optical context. These solutions do not require the presence of the delayed response of the nonlinear refractive index, such that, they exist regardless of the term previously considered essential for stabilization. The existence of these solitons was predicted by a perturbation approach, and then confirmed by solving the ordinary differential equations, resulting from a similarity reduction, and also by applying a linear stability analysis. We found that these solitons exist for a large region of the parameter space and possess very asymmetric amplitude profiles as well as a complicated chirp characteristic.