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Publications

Publications by Paulo Caldas

2010

Optical Fiber Sensing System Based on Long-Period Gratings for Remote Refractive Index Measurement in Aqueous Environments

Authors
Silva, C; Coelho, JMP; Caldas, P; Frazao, O; Jorge, PAS; Santos, JL;

Publication
FIBER AND INTEGRATED OPTICS

Abstract
In the field of aqueous environment studies, long-period fiber gratings are very attractive for the real-time monitoring of physical parameters, such as temperature and salinity. However, due to the fiber jacket removal, these are fragile devices when applied in real conditions, where mechanical loads and contamination with algae and other organic materials must be taken into account. This work describes a refractive index sensing head that has been developed and characterized for in situ measurement of water salinity and resistance to hard conditions.

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.

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.

2004

<title>Optical temperature measurement configuration for fluorescence-based oxygen sensors</title>

Authors
Jorge, PAS; Caldas, P; Rosa, CC; Oliva, AG; Marques, MB; Santos, JL;

Publication
Second European Workshop on Optical Fibre Sensors

Abstract

2007

<title>Modal interferometer based on a single non-adiabatic fibre taper</title>

Authors
Frazão, O; Caldas, P; Santos, JL; Araújo, FM; Ferreira, LA;

Publication
Third European Workshop on Optical Fibre Sensors

Abstract

2008

<title>Fibre refractometer based on a Fabry-Pérot interferometer</title>

Authors
Silva, SFO; Frazão, O; Caldas, P; Santos, JL; Araújo, FM; Ferreira, LA;

Publication
19th International Conference on Optical Fibre Sensors

Abstract

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