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Publicações

Publicações por Gaspar Rego

2008

Estimation of the fiber temperature during an arc-discharge

Autores
Rego, G; Santos, LMNBF; Schroder, B;

Publicação
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS

Abstract
The formation mechanisms and properties of arc-induced gratings are intrinsically related to the temperature attained by the fiber during arc exposure. In this work, we present further results oil the estimation of the fiber temperature based oil the use of electrically insulated thermocouples. Computer simulations show that under typical arc discharge conditions, the fiber reaches steady-state thermal equilibrium in less than half a second, having a peak temperature of about 1350 degrees C (C) 2008 Wiley Periodicals, Inc.

2008

Optical filters for fiber lasers and amplifiers

Autores
Rego, G;

Publicação
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS

Abstract
We discuss the writing of arc-induced long-period fiber gratings to be used as optical filters in Er/Yb fiber lasers and for flattening the gain spectra of Er-doped fiber amplifiers. A new approach for the fabrication of filters with complex profiles is also presented. (c) 2008 Wiley Periodicals, Inc.

2008

Apodization of fiber Bragg gratings by using arc discharges

Autores
Romero, R; Rego, G; Marques, PVS;

Publicação
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS

Abstract
The electric arc technique is used to apodize fiber Bragg gratings (FBGs). Arc discharges applied to the ends of the grating produce a smoothing of the refractive-index modulation profile reducing the sidelobes of the reflection spectrum at longer wavelengths. A sidelobe reduction of 17 dB was obtained. (c) 2007 Wiley Periodicals, Inc.

2008

Long-period gratings arc-induced in B/Ge codoped fibers: Thermal behavior and uniform exposure to UV-radiation

Autores
Rego, G;

Publicação
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS

Abstract
The thermal behavior of long-period gratings arc-induced in B/Ge codoped fibers is presented. We also demonstrated the possibility to erase gratings written in Ge-doped and B/Ge codoped fibers through uniform exposure to UV-laser radiation. The gratings spectra were afterward recovered by thermal annealing. permanent thermally induced refractive index changes were found. (C) 2007 Wiley Periodicals, Inc.

2005

Stress profiling of arc-induced long-period gratings written in pure-silica-core fibers

Autores
Rego, G; Carvalho, JCC; Marques, PVS;

Publicação
17th International Conference on Optical Fibre Sensors, Pts 1 and 2

Abstract
Long-period gratings were written in a pure-silica-core fiber using the electric arc technique. To assess the influence of stress relaxation on grating formation, tomographic stress measurements were performed inside the grating. No stress annealing could be observed within the accuracy of the stress measurement, suggesting a negligible photo-elastic contribution to the arc-induced perturbation of the index profile. In contrast, stress relaxation was found inside a splice of pure-silica-core fiber where discharge conditions are different, indicating the general potential to alter the fibers stress and thus the index profile using an electric arc.

1995

Active fibre characterisation with passive measurements

Autores
ANACLETO, JMS; MORAIS, M; REGO, G; SOARES, ODD;

Publicação
TRENDS IN OPTICAL FIBRE METROLOGY AND STANDARDS

Abstract

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