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Publications

Publications by Manuel Joaquim Marques

2010

A Raman intensity sensor induced by the Rayleigh scattering in a ring configuration

Authors
Correia, C; Baptista, JM; Marques, MB; Frazao, O;

Publication
FOURTH EUROPEAN WORKSHOP ON OPTICAL FIBRE SENSORS

Abstract
In this work, a laser sensor that uses the multipath interference produced inside a ring cavity to measure the power loss induced by a moving taper intensity sensor is described. The laser is created due to the virtual distributed mirror formed by the Rayleigh scattering produced in a dispersion compensating fibre when pumped by a Raman laser. Two laser peaks were formed, one of them is obtained by the Raman gain (1555 nm) inside the ring and the second is created by the combination of the Raman gain and the Rayleigh scattering (1565 nm). A taper sensor is used as displacement sensor and with the increases of losses the second laser peak amplitude is reduced. In the process the first peak is maintained constant and can be used as reference level.

2011

A Raman laser intensity sensor induced by the cooperative Rayleigh scattering in a ring configuration

Authors
Baptista, JM; Correia, C; Marques, MB; Frazao, O;

Publication
LASER PHYSICS

Abstract
In this work, a laser sensor is described that uses the multipath interference produced inside a ring cavity to measure the power loss induced by a moving taper intensity sensor. The laser is created due to the virtual distributed mirror formed by the Rayleigh scattering produced in a dispersion compensating fiber when pumped by a Raman laser. Two laser peaks were formed, one of them is obtained by the Raman gain (1555 nm) inside the ring and the second is created by the combination of the Raman gain and the Rayleigh scattering (1565 nm). A taper sensor is used as displacement sensor and when the losses is applied in the taper the second laser peak is reduced and the first peak is maintained constant and can be used as reference level.

2012

Temperature independent Refractive Index measurement using White Light Interferometry

Authors
Gouveia, C; Zibaii, M; Latifi, H; Marques, MJ; Baptista, JM; Jorge, PAS;

Publication
22ND INTERNATIONAL CONFERENCE ON OPTICAL FIBER SENSORS, PTS 1-3

Abstract
In this work a fiber optic interferometric system for differential refractive index measurement is described. The system is based on a white light Mach-Zehnder configuration, with serrodyne phase modulation, to interrogate two similar non-adiabatic tapered optical fiber sensors in a differential scheme. In this situation it is possible to measure the refractive index independent of temperature. Signal processing with low cost digital instrumentation developed in Labview environment allows a detectable change in refractive index of Delta n approximate to 2x10(-6), which is, from the best of our knowledge the highest resolution achieved using a fiber taper device. The results demonstrate the potential of the proposed scheme to operate as chemical and biological sensing platform.

2006

Brillouin fibre laser sensor for strain and temperature discrimination

Authors
Frazão, O; Marques, JM; Santos, JL; Marques, MB; Baptista, JM;

Publication
Optics InfoBase Conference Papers

Abstract
In this work, a Brillouin fibre laser sensor for strain and temperature discrimination is presented. The fibre laser sensor consists in a Fabry-Pérot cavity with 20 meters of optical fibre between two Bragg gratings. © 2006 OSA/OFS 2006.

2006

Optical fibre intensity sensor referenced by stimulated Brillouin scattering

Authors
Baptista, JM; Marques, JM; Frazao, O; Santos, S; Santos, JL; Marques, MB;

Publication
Optics InfoBase Conference Papers

Abstract
An optical fibre intensity sensor referenced by stimulated Brillouin scattering is presented. The sensor uses Fresnel reflection at the sensor fibre end and employs an adequate relationship between Brillouin and Rayleigh scattering and Fresnel reflection. © 2006 OSA/OFS 2006.

2009

<title>Ultra-narrow band transmission filter using a phase-shift chirped fiber Bragg grating concatenated with a broadband rejection filter</title>

Authors
Pereira, DA; Araújo, FM; Ferreira, LA; Marques, MB; Santos, JL; Carmo, JP;

Publication
20th International Conference on Optical Fibre Sensors

Abstract

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