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Publications

Publications by José Luís Santos

2004

Fiber Bragg grating sensing system for simultaneous measurement of salinity and temperature

Authors
Pereira, DA; Frazao, O; Santos, JL;

Publication
OPTICAL ENGINEERING

Abstract
A fiber optic sensing system for simultaneous measurement of temperature and salinity based on fiber Bragg grating technology is presented. The fabrication process, which relies on chemical etching of the fibre, is described and its performance is evaluated. Theoretical and experimental results are given, which are summarized on the obtained resolutions of +/-0.06degreesC/ rootHz and +/- 0.2parts per thousand./ rootHz for temperature and salinity, respectively. (C) 2004 Society of Photo-Optical Instrumentation Engineers.

2012

Simultaneous measurement of strain and temperature based on clover microstructured fiber loop mirror

Authors
Perez Herrera, RA; Andre, RM; Silva, SF; Becker, M; Schuster, K; Kobelke, J; Lopez Amo, M; Santos, JL; Frazao, O;

Publication
Proceedings of SPIE - The International Society for Optical Engineering

Abstract
In this work, an all-fiber loop mirror using a clover microstructured fiber for the simultaneous measurement of temperature and strain is presented. The sensing head is formed by a short piece of clover microstructured fiber with 35 mm length. The geometry of the fiber allowed observing different interferences created by the microstructured fiber core section. Different sensitivities to temperature and strain were obtained and, using a matrix method, it is possible to discriminate both physical parameters. Resolutions of ±2°C and ±11 µe, for temperature and strain, respectively, were attained. © 2012 SPIE.

2010

Interrogation of Microresonators Using Multimode Fibers

Authors
Caldas, P; Jorge, PAS; Araujo, FM; Ferreira, LA; Rego, G; Santos, JL; Berneschi, S; Cosi, F; Soria, S; Pelli, S; Conti, GN;

Publication
FOURTH EUROPEAN WORKSHOP ON OPTICAL FIBRE SENSORS

Abstract
In this work we describe the characterization of high Q optical microresonators using an all fiber based system. Silica microspheres fabricated on a fiber tip by electric arc discharge are characterized using a simple interrogation system based on an adiabatic fiber taper coupler and on the collection of scattered radiation by a multimode fiber.

2005

Strain and temperature discrimination using a Hi-Bi grating partially exposed to chemical etching

Authors
Frazao, O; Pereira, DA; Santos, JL; Araujo, FM; Ferreira, LA;

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

Abstract
This paper presents a sensing head based on a Bragg grating written in an elliptical cladding Hi-Bi fibre partially exposed to chemical etching for reduction of the cladding diameter. With this sensing head geometry different strain and similar temperature sensitivities are achieved.

2000

Analysis of the flyback effects on the serrodyne interferometric demodulation of fiber optic Bragg grating sensors

Authors
Jorge, PAS; Ferreira, LA; Santos, JL;

Publication
OPTICAL ENGINEERING

Abstract
An analysis is performed of the degradation of the signal readout of fiber optic Bragg grating sensors demodulated using the serrodyne interferometric technique. Experimental results are presented that validate the analysis. It is also shown that synchronous detection of the interferometric signal referenced to the serrodyne waveform that modulates the phase of the readout interferometer allows the elimination of the system do offset introduced by the serrodyne flyback, (C) 2000 Society of Photo-Optical Instrumentation Engineers.

2002

Electrical current metering with a dual interferometric configuration and serrodyne signal processing

Authors
Jorge, PAS; Caldas, P; Ferreira, LA; Ribeiro, ABL; Santos, JL; Farahi, F;

Publication
OFS 2002: 15TH OPTICAL FIBER SENSORS CONFERENCE TECHNICAL DIGEST

Abstract
Theoretical and experimental results were presented which validated a new dual interferometric configuration with serrodyne processing for the remote sensing of electrical current. Linearity and waveform reproduction at 50 Hz were observed and a current resolution (˜22.4 ArmsHz- 1/2) was obtained. The utilization of the proposed interferometric concept to simultaneously perform metering and relaying current measurements was also addressed. © 2002 IEEE.

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