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Publications

Publications by CTM

2003

Study of the properties of arc-induced long-period gratings and Bragg gratings in B/Ge doped fibers

Authors
Rego, G; Santos, JL; Marques, PVS; Salgado, HM;

Publication
Optics InfoBase Conference Papers

Abstract
We have investigated the possibility to erase arc-induced long period gratings through uniform exposure to UV-laser radiation and their potential recover by thermal annealing. The temperature stability of UV/arc-induced gratings is also presented. © 2000 Optical Society of America.

2003

Spectral response of chirped fibre Bragg gratings written in Erbium doped fibres

Authors
Romero, R; Salgado, HM; Frazão, O; Marques, PVS; Santos, JL;

Publication
Optics InfoBase Conference Papers

Abstract
A chirped fibre Bragg grating was written in an Erbium doped fibre. It was found that the slope of the reflected spectral power could be tuned by changing the pump power. The gratings fabricated were demonstrated to be useful in the development of a technique for optical interrogation of FBGs sensing heads with tunable sensitivity. © 2003 OSA/BGPP.

2003

Optical cross-connect based on tuneable FBG-OC with full scalability and bidirectionality

Authors
Frazao, O; Terroso, I; Carvalho, JP; Salgado, HM;

Publication
OPTICS COMMUNICATIONS

Abstract
We propose and demonstrate an architecture of a 2 x 2 port optical cross-connect (OXC) using tuneable fibre Bragg gratings and optical circulators. The proposed OXC is scalable to N x N ports owing to the cascadability of individual routing modules, which perform routing of specific wavelength channels. The performance of the cross-connect is also experimentally evaluated.

2003

Tunable L-band erbium-doped fibre ring laser by means of induced cavity loss using a fibre taper

Authors
Melo, M; Frazao, O; Teixeira, ALJ; Gomes, LA; da Rocha, JRF; Salgado, HM;

Publication
APPLIED PHYSICS B-LASERS AND OPTICS

Abstract
In this paper, we present a continuous-wave tunable fibre ring laser operating in the L-band. A bi-directional pumped L-band erbium-doped fibre amplifier provides gain to the loop. Tunability is achieved by bending a single-mode fibre taper using a micrometer drive, controlling in this way the spectral cavity losses. Laser emission is achieved between 1587 and 1606 nm, and low variation of the output laser power is observed over all the tuning range.

2003

Fibre Bragg grating interrogation technique based on a chirped grating written in an erbium-doped fibre

Authors
Romero, R; Frazao, O; Marques, PVS; Salgado, HM; Santos, JL;

Publication
MEASUREMENT SCIENCE & TECHNOLOGY

Abstract
A fibre Bragg grating interrogation technique with tunable sensitivity is reported. It relies on the utilization of the edge filtering concept applied to a chirped fibre Bragg grating (CFBG) written in an erbium-doped fibre as the processing element. Through the combination of the optical gain properties of the erbium-doped fibre and of the distributed wavelength reflection characteristics of the CFBG, it is possible to achieve different reading sensitivities and amplification of the remote sensing signal.

2003

New technique to mechanically induce long-period fibre gratings

Authors
Rego, G; Fernandes, JRA; Santos, JL; Salgado, HM; Marques, PVS;

Publication
OPTICS COMMUNICATIONS

Abstract
A full characterization of reversible long-period fibre gratings produced through the wind of a string around a fibre/grooved tube set is presented. This technique enables a good control over the gratings isolation loss-peaks and has high repeatability. The tunability of the resonant wavelengths through the etching of the fibres cladding, prior to perform the gratings, have been investigated. These mechanically induced long-period fibre gratings have shown high sensitivity to loads.

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