Publications

Publications by CAP

1999

<title>Optical amplification in localized doping of Er:Ti:LiNbO3 waveguides</title>

Authors
de Almeida, JMMM; Leite, AMPP; Amin, J;

Publication
Rare-Earth-Doped Materials and Devices III

Abstract

1999

Optical amplification in localized doping Er : Ti : LiNbO3 waveguides

Authors
de Almeida, JMMM; Leite, AMPP; Amin, J;

Publication
RARE-EARTH-DOPED MATERIALS AND DEVICES III

Abstract
An investigation on optical amplification in Ti waveguides in LiNbO3 doped with Er ions by thermal diffusion of thin metallic stripes is presented. The possibility of fabricating efficient optical amplifiers in LiNbO3 substrates realized by localization of the dopant on surface areas of the crystals was theoretically evaluated and the feasibility of fabricating efficient amplifiers in such doped structures was experimentally verified. It was concluded that the localized doping technique allows optimization of amplifier performance through adjustment of the active region geometry to the mode intensity profile.

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1998

Comparison study of the Mach-Zehnder and Michelson topologies for resonant fiber optic intensity sensors

Authors
Baptista, JM; Santos, JL; Lage, AS;

Publication
OPTICAL AND FIBER OPTIC SENSOR SYSTEMS

Abstract
A theoretical and experimental study of the self-referencing resonant fiber optic intensity sensors based respectively on Michelson and Mach-Zehnder configurations is conducted. Sensor linearity and sensitivity are addressed, being also considered sensors design and optimization.

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1998

<title>Extended-range interrogation scheme for fibre Bragg grating sensors using a multimode laser diode</title>

Authors
Moreira, PJ; Ferreira, LAA; Santos, JL; Farahi, F;

Publication
European Workshop on Optical Fibre Sensors

Abstract

1998

<title>Simultaneous strain and temperature sensing using an interferometrically interrogated fibre Bragg grating written in bowtie fibre</title>

Authors
Ferreira, LAA; Araujo, FM; Santos, JL; Farahi, F;

Publication
European Workshop on Optical Fibre Sensors

Abstract

1998

Demodulation scheme for fiber Bragg grating sensors based on active control of the spectral response of a wavelength division multiplexer

Authors
Araujo, FM; Ferreira, LA; Santos, JL; Farahi, F;

Publication
APPLIED OPTICS

Abstract
We present a closed-loop technique for measuring wavelength shifts associated with fiber Bragg gratings by using a fused biconical wavelength division multiplexer (WDM). The spectral response of the WDM is actively tuned by stretching of the coupling region to maintain a fixed coupling ratio at the reflected Bragg wavelength. The closed-loop operation allows sensitivities usually associated with a highly selective WDM to be obtained without compromising the measurement range. A simple theoretical model is presented together with experimental results for temperature and strain measurements. (C) 1998 Optical Society of America.

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