Publications

Publications by CAP

2005

Short in-fibre Bragg grating structure for simultaneous measurement of strain and temperature

Authors
Frazao, O; Melo, M; Romero, R; Marques, PVS; Araujo, FM; Ferreira, LA; Santos, JL;

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

Abstract
The study of a single short length Bragg grating for sensing applications is presented. The dependences of the central wavelength, reflected optical power and spectral width of a 250 mu m length grating on strain and temperature are analyzed. The obtained results indicate the feasibility of this novel sensing head for simultaneous measurement of strain and temperature.

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2005

Optical fiber sensors for nuclear environments

Authors
Rego G.M.; Fernandez A.F.; Santos J.L.; Salgado H.M.; Berghmans F.; Gusarov A.;

Publication
Recent Advances in Multidisciplinary Applied Physics

Abstract

2005

Measurement of the salinity in water through long-period gratings arc-induced in pure-silica-core fibers

Authors
Rego G.; Santos J.; Salgado H.;

Publication
Recent Advances in Multidisciplinary Applied Physics

Abstract

2005

Arc-induced long-period gratings

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

Publication
FIBER AND INTEGRATED OPTICS

Abstract
The electric arc technique allows the inscription of long-period gratings (LPGs) virtually in all types of fibers, including non-photosensitive fibers, the case of non-Ge doped photonic crystal fibers being of particular interest. LPGs written in standard fibers using this technique have shown a high thermal stability. Also, the resistance to. - radiation of LPGs arc-induced in pure-silica-core fibers is being assessed and the achieved results are very promising. We have also demonstrated that the combination of arc-induced LPGs and UV-induced fiber Bragg gratings (FBGs) leads to sampled FBGs that are able to address sensing functionalities with enhanced performance. Therefore, as a result of their properties, gratings induced by arc-discharges can find a wide range of applications in optical communications as well as in fiber sensing.

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2005

Simultaneous measurement of temperature and strain based on arc-induced long-period fibre gratings

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

Publication
ELECTRONICS LETTERS

Abstract
A study on arc-induced long-period fibre gratings (LPFGs) revealed that their strain sensitivity depends on the electric current of the arc discharge. Based on that property, a sensor scheme comprising two concatenated LPFGs was implemented for discrimination of temperature and strain effects. This sensor presented resolutions of +/-0.1 degreesC/rootHz and +/-35 muepsilon/rootHz, respectively.

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2005

Arc-induced long-period gratings in aluminosilicate glass fibers

Authors
Rego, G; Falate, R; Santos, JL; Salgado, HM; Fabris, JL; Semjonov, SL; Dianov, EM;

Publication
OPTICS LETTERS

Abstract
Permanent long-period gratings were written using arc discharges in two aluminosilicate fibers, one of which was doped with erbium. Reversible gratings were also mechanically induced in both fibers. The thermal behavior of the arc-induced gratings was investigated at up to 1100 degrees C. It was found that the shift of the resonant wavelengths exhibited a well-defined linear dependence on temperature up to 700 degrees C. (c) 2005 Optical Society of America.

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