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Publications

Publications by Orlando Frazão

2017

Polymer and tapered silica fiber connection for polymer fiber sensor application

Authors
Ferreira, MFS; Gomes, AD; Kowal, D; Statkiewicz Barabach, G; Mergo, P; Frazao, O;

Publication
THIRD INTERNATIONAL CONFERENCE ON APPLICATIONS OF OPTICS AND PHOTONICS

Abstract
A new type of polymer and silica connection is proposed. A tapered SMF- 28 silica optical fiber tip is fabricated using a CO2 laser by focusing and stretching the fiber. The tapered silica tip is inserted in one of the holes of a microstructured polymer optical fiber using a 3D alignment system. Using a supercontinuum source, the spectrum is observed after one and after two connections. The polymer fiber is characterized in curvature while using the previous connection.

2017

Strain sensor based on hollow microsphere Fabry-Perot cavity

Authors
Monteiro, CS; Silva, SO; Frazao, O;

Publication
THIRD INTERNATIONAL CONFERENCE ON APPLICATIONS OF OPTICS AND PHOTONICS

Abstract
Fusion splicing technique was explored for the fabrication of two sensing structures based on hollow microsphere Fabry-Perot cavity. The first sensor proposed was fabricated with a hollow microsphere tip, working as a probe sensor. This structure was studied for lateral load pressure, yielding a 1.56 +/- 0.01 nm/N sensitivity. The second sensing structure relied on an in-line hollow microsphere, which allowed the detection of lateral load, with a sensitivity of 2.62 +/- 0.02 nm/N. Furthermore, the proposed structure enabled strain sensing, with a sensitivity of 4.66 +/- 0.03 pm/mu epsilon. The two sensing structures were subjected to temperature, presenting low thermal cross-sensitivity.

2014

Evaporation of volatile compounds in suspended-core fibers

Authors
Moura, JP; Baierl, H; Auguste, JL; Jamier, R; Roy, P; Santos, JL; Frazao, O;

Publication
OPTICS LETTERS

Abstract
A sensing configuration for fluid evaporation monitoring using a suspended-core fiber tip is proposed. Strong differences between the evaporation processes of acetone and isopropyl alcohol were observed, both in terms of the signal's intensity fluctuations and total duration. In each fluid, the main signal variations were due to changes in reflectivity inside a collapsed region of the suspended-core fiber near the spliced interface with a standard single-mode fiber. After further analysis with a wider array of substances, this configuration could, in the future, be used to detect and study the evaporation of different volatile organic compounds. (C) 2014 Optical Society of America

2013

Figure-of-eight cavity fiber laser based torsion sensor

Authors
Ferreira, MS; Santos, JL; Mergo, P; Frazao, O;

Publication
8TH IBEROAMERICAN OPTICS MEETING AND 11TH LATIN AMERICAN MEETING ON OPTICS, LASERS, AND APPLICATIONS

Abstract
A torsion active sensor based on a figure-of-eight configuration is presented. The interferometric fiber loop mirror, composed by a section of photonic crystal fiber, also acts as a sensing element. When torsion is applied over a range of 180 degrees, a sensitivity of 7.13 pm/degree is achieved. Besides, this configuration can also be used to measure optical power variations and it presents low sensitivity to temperature.

2014

Multiparameter measurement using a double-Y-shaped suspendedcore fiber in a fiber loop configuration

Authors
Silva, SF; Baierl, H; Auguste, JL; Jamier, R; Roy, P; Baptista, JM; Santos, JL; Frazao, O;

Publication
23RD INTERNATIONAL CONFERENCE ON OPTICAL FIBRE SENSORS

Abstract
In this work, an all-fiber loop mirror using a four-bridge silica fiber with a double-Y-shaped suspended-core is presented for the measurement of strain and torsion. The sensing head is formed by a section of the microstructured fiber with 90 mm in length. The fiber loop sensor allowed observing a distinct interference pattern as a result of the geometry of the core fiber. Different sensitivities to strain and torsion were obtained, namely, -5.11 pm/mu e and +/- 1.34 pm/degree.

2016

CAVITY RING-DOWN TECHNIQUE FOR REMOTE SENSING

Authors
Silva, S; Marques, MB; Frazao, O;

Publication
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS

Abstract
This work demonstrates the viability of using a cavity ring-down (CRD) technique for remote sensing. A conventional CRD configuration is used where an optical circulator is added inside the fiber loop to couple 19 km of optical fiber with a gold mirror at its end with the purpose of remote sensing. As a proof-of-concept, an intensity sensor based on an eight-figure configuration is used at the end of the 19 km of fiber for displacement sensing. (C) 2016 Wiley Periodicals, Inc.

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