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Publications

Publications by CAP

2001

Interrogation of low-finesse Fabry-Perot cavities based on modulation of the transfer function of a wavelength division multiplexer

Authors
Misas, CJ; Araujo, FMM; Ferreira, LA; Santos, JL; Lopez Higuera, JM;

Publication
JOURNAL OF LIGHTWAVE TECHNOLOGY

Abstract
A theoretical and experimental investigation is reported on a novel all-fiber technique for interrogation of interferometric low-finesse Fabry-Perot cavities, It is based on the modulation of the spectral transfer function of a wavelength-division multiplexer, Results are given when both serrodyne and sinusoidal modulation formats are considered.

2001

Multiplexing of fibre optic intensity sensors using fused biconical wavelength selective couplers

Authors
Abad, S; Araujo, FM; Ferreira, LA; Santos, JL; Lopez Amo, M;

Publication
ELECTRONICS LETTERS

Abstract
Fused biconical wavelength division multiplexers have been used to replace standard couplers in an intensity-sensor multiplexing network. The wavelength-selective power splitting and the low insertion losses of these devices (< 0.2dB) improve the power budget, while providing network overall optical isolations > 30dB. With this isolation, crosstalk effects in the network are proven to be negligible.

2001

Novel self-referenced microbend optical fibre sensor as a load cell for structural monitoring

Authors
Baptista, JM; Frazao, O; Felix, C; Ferreira, LA; Araujo, FM; Santos, JL; Lage, A; Figueiras, JA;

Publication
COMPOSITES IN CONSTRUCTION

Abstract
In this paper we present a novel microbend optical fibre sensor embedded in composite material, which acts as a load cell for structural monitoring in civil engineering. The sensing system is based on a self-referenced fibre optic intensity sensor supported by a Michelson topology with optical feedback. The sensing system is tested in a sand testing bed for different values of load. Results are presented and discussed.

2001

Measurement of refractive index in oils using a self-referenced fiber optic intensity sensor

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

Publication
LEOS 2001: 14TH ANNUAL MEETING OF THE IEEE LASERS & ELECTRO-OPTICS SOCIETY, VOLS 1 AND 2, PROCEEDINGS

Abstract
A sensor for measurement of refractive index in oils was discussed. The sensor comprised a fiber based-device sensing head placed in a self-referenced fiber optic intensity sensor. The sensing head works on the principle of change of the refractive index of the medium that surrounds the unclad portion of multimode fiber. This results in different attenuation of the guided modes that propagate in the fiber. The injection current of the optical source was swept in frequency to obtain the transfer function.

2001

Fiber Bragg Gratings for telecommunications

Authors
Teixeira, ALJ; Lima, MJN; Frazao, O; da Rocha, JRF;

Publication
ICTON 2001: 3RD INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS, CONFERENCE PROCEEDINGS

Abstract
Fiber Bragg Gratings (FBG's) are nowadays widely used in various fields, including telecommunications. Since emergence, this component has found many applications due to its properties, versatility and variety of controllable parameters that can shape in various manners its spectral properties. These devices have the advantage of being built of fiber and they are widely used in mono and multichannel networks.

2001

Fibre Bragg grating for telecommunications applications: Tuneable thermally stress enhanced OADM

Authors
Andre, PS; Pinto, JL; Abe, I; Kalinowski, HJ; Frazao, O; Araujo, FM;

Publication
Journal of Microwaves and Optoelectronics

Abstract
This paper presents some aspects of the production, characterization and implementation of fibre Bragg grating as a key element for selective filtering in optical communications. Theory, fabrications and applications of the Fibre Bragg grating for a specific tuneable optical add-drop multiplexer (OADM) are presented. The OADM performance on a 2.48832 Gbit/s dense wavelength division multiplexing optical communications system with 95 km is reported. The power penalty for the removed channels was less than 0.1 dB. We obtain good agreement between the FBG behaviour the OADM performance with the numerical simulations results. Copyright SBMO.

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