2013
Authors
Rodriguez Cobo, L; Marques, AT; Lopez Higuera, JM; Santos, JL; Frazao, O;
Publication
Proceedings of SPIE - The International Society for Optical Engineering
Abstract
Several easy-to-manufacture designs based on a pair of Fiber Bragg Gratings structure embedded in Carbon Fiber Reinforced Plastic (CFRP) have been explored. These smart composites can be used for strain and temperature discrimination. A Finite Elements Analysis and Matlab software were used to study the mechanical responses and its optical behaviors. The results exhibited different sensitivity and using a matrix method it is possible to compensate the thermal drift in a real application keeping a simple manufacture process. © 2013 SPIE.
2013
Authors
Gouveia, C; Chesini, G; Cordeiro, CMB; Baptista, JM; Jorge, PAS;
Publication
SENSORS AND ACTUATORS B-CHEMICAL
Abstract
A fiber optic sensor for simultaneous measurement of refractive index and temperature is presented. The sensing probe is realized by introducing a multimode interference device inside a high birefringence fiber loop mirror resulting in a configuration capable of refractive index and temperature discrimination. The multimode interference peak is sensitive to the surrounding refractive index (90 nm/RIU) and slightly responsive to the temperature (0.01 nm/ degrees C). On the other hand, the birefringent fiber loop mirror is highly sensitive to temperature (2.36 nm/ degrees C) and it has almost no response to refractive index. Using a power ratiometric peak detection scheme, a temperature independent refractive index measurement can be achieved with a resolution of +/- 2.25 x 10(-5) RIU.
2013
Authors
Queiros, RB; Gouveia, C; Fernandes, JRA; Jorge, PAS;
Publication
FIFTH EUROPEAN WORKSHOP ON OPTICAL FIBRE SENSORS
Abstract
An evanescent wave fiber optic sensor for detection of E. coli outer membranes proteins (EcOMPs) is presented. The sensing probe is achieved by the functionalization of a Long Period Grating (LPG) inscribed in a single mode fiber (SMF28) with poly-L-lysine (PLL) resulting in a label-free configuration capable of specific recognition of EcOMPs in waters due to the resonance wavelength shift variation owing to refractive index changes of the medium (approximate to 100 nm/RIU). The sensing head was characterized and tested against EcOMP and applied to spiked environmental water samples. The sensor displayed linear responses in the range of 1x10(-10) M to 1x10(-8) M EcOMP and is regenerated (under low pH conditions) and the deviation of the subsequent detection was less than 0.1 %.
2013
Authors
Ferreira, MS; Bierlich, J; Unger, S; Schuster, K; Santos, JL; Frazao, O;
Publication
Optics InfoBase Conference Papers
Abstract
A Fabry-Pérot microcavity tip sensor based on the post-process of a special design double-cladding optical fiber is proposed. The sensor is subjected to temperature variations in both air and water. © OSA 2013.
2013
Authors
Ferreira, MS; Bierlich, J; Unger, S; Schuster, K; Santos, JL; Frazao, O;
Publication
IEEE PHOTONICS TECHNOLOGY LETTERS
Abstract
A Fabry-Perot microcavity tip sensor fabricated by post-processing of a special design double-cladding optical fiber is proposed. The produced fiber has a pure silica core, an outer cladding, and an inner silica cladding surrounding the core doped with phosphorous. When subjected to chemical etching post-processing, the whole ring region is removed and light is guided in the core region. The sensing head is created by splicing this fiber to single mode fiber and applying chemical etching to the fiber end. The core is forming a tip and it is thus surrounded by air. The Fabry-Perot microcavity tip sensor is subjected to temperature, and a sensitivity of 15.5 pm/degrees C is obtained.
2013
Authors
J. Gouveia, CA; M., J; A.S., P;
Publication
Current Developments in Optical Fiber Technology
Abstract
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