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Publicações

Publicações por Paulo Vicente Marques

2009

Temperature and strain characterization of bragg gratings impressed with femtosecond laser radiation in suspended-silica-core fibers

Autores
Fernandes, LA; Becker, M; Frazao, O; Rothhardt, M; Bruckner, S; Schuster, K; Kobelke, J; Santos, JL; Marques, PVS;

Publicação
Proceedings of SPIE - The International Society for Optical Engineering

Abstract
Fiber Bragg Gratings (FBG) are widely used in various fields, including optical fiber sensors. In this work, the temperature and strain response of C-band FBG in pure silica four-leaf clover shaped suspended-core fibers was analyzed. These FBGs were fabricated by femtosecond laser exposure, which enabled the refractive index modulation of the pure-silica-core of the fibers. We compared the Bragg wavelength variation with strain and temperature for two different suspended-core fibers (256b2 and 256b5). The 256b2 fiber has a core diameter of 4,9 µm and a hollow hole inside the core with 1,4 µm; the 256b5 fiber has a solid silica core with a 7,2 µm diameter. For strain and temperature characterization, the sensing head was attached to a translation stage with a resolution of 1 µm and was placed in a tubular oven, which permits a temperature reading to be set with an error smaller than 0,1 °C. Both have shown the same sensitivity to strain (1,2 pm/µe) but different sensitivity to temperature variation (8,4 pm/°C and 10 pm/°C respectively). The relative difference between the thermal coefficients of the two selected Bragg signatures is 16%. The results obtained indicate that these gratings can be used in optical fiber sensing, for example in the context of the important problem of simultaneous strain and temperature measurement. © 2009 SPIE.

2002

Apodisation of uniform Fibre Bragg Gratings using electric arc discharges

Autores
Rego, G; Romero, R; Frazao, O; Marques, PVS; Salgado, HM;

Publicação
PROCEEDINGS OF 2002 IEEE/LEOS WORKSHOP ON FIBRE AND OPTICAL PASSIVE COMPONENTS

Abstract
We report the use of the electric arc technique to apodise Fibre Bragg Gratings (FBG). Electric arc discharges applied at the ends of the grating produce a smoothing of the refractive index modulation profile which reduces the side lobes at longer wavelengths. Using this technique, a FBG was apodised with a side lobe reduction of 17 dB.

2004

<title>Measurement of the temperature of an optical fiber submitted to an electric arc discharge</title>

Autores
Rego, GM; Marques, PVS; Salgado, HM; Santos, JL;

Publicação
Second European Workshop on Optical Fibre Sensors

Abstract

2005

<title>Simultaneous temperature and strain measurement based on arc-induced long-period fiber gratings</title>

Autores
Rego, GM; Falate, R; Kalinowski, HJ; Fabris, JL; Marques, PV; Salgado, HM; Santos, JL;

Publicação
17th International Conference on Optical Fibre Sensors

Abstract

2005

Chirped fibre Bragg grating based multiplexer and demultiplexer for DWDM applications

Autores
Romero, R; Frazao, O; Floreani, F; Zhang, L; Marques, PVS; Salgado, HM;

Publicação
OPTICS AND LASERS IN ENGINEERING

Abstract
A multiplexer/demultiplexer for 100GHz channel spacing based on chirped fibre Bragg gratings with different bandwidths and optical circulators is presented. The spectral characteristics, specifications and operation of these passive devices are described, showing its potential use in dense wavelength division multiplexing (DWDM) applications.

2002

Sampled fibre Bragg grating sensors for simultaneous strain and temperature measurement

Autores
Frazao, O; Romero, R; Rego, G; Marques, PVS; Salgado, HM; Santos, JL;

Publicação
ELECTRONICS LETTERS

Abstract
A new scheme is presented for simultaneous measurement of strain and temperature using a sampled fibre Bragg grating based on a long period structure written using the electric are technique. The temperature and strain measurement resolutions are estimated to be +/-0.50degreesC/rootHz and +/-3.38 muepsilon/rootHz, respectively.

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