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Bi-core optical fiber for sensing of temperature, strain and torsion
Lobo Ribeiro, Antonio B.; Silva, S F O; Frazão, O; Santos, J LBi-core optical fiber structures are studied for applications in sensing. In this paper, an analysis is performed on the spectral characteristics of light propagating in these fibers with central launching core illumination from a standard single mode fiber. Reflective and transmissive configurations are addressed. The characteristics of a reflective bi-core fiber structure for measurement of strain, temperatur...
Refractive Laser Surgery: What's New?
Lobo Ribeiro, Antonio B.; Salgado-Borges, J.The correction or improvement of common vision problems (such as, myopia, hypermetropia and astigmatism) through refractive laser surgery, as a permanent alternative to eyeglasses or contact lenses, has been growing in demand over recent years. The most common refractive laser surgery is the laser in-situ keratomileusis (LASIK) and its recent technological variants with improvements. Nevertheless, the generalit...
Fiber optical sensors in biomechanics: research, technology, and applications i...
Roriz, P; Lobo Ribeiro, Antonio B.This chapter introduces the use of fiber optic sensors in biomechanics applications. It starts by presenting the field of biomechanics and the technical reasons that make fiber optic sensors an interesting tool for measuring in biomechanics applications. It then explains the application of fiber optic sensors in the biomechanics of rigid bodies, then moves on to deformable bodies, and finishes with fluids, in p...
Review of fiber-optic pressure sensors for biomedical and biomechanical applica...
Roriz, Paulo; Frazão, Orlando; Lobo Ribeiro, Antonio B.; Santos, José L.; Simões, José A.As optical fibers revolutionize the way data is carried in telecommunications, the same is happening in the world of sensing. Fiber-optic sensors (FOS) rely on the principle of changing the properties of light that propagate in the fiber due to the effect of a specific physical or chemical parameter. We demonstrate the potentialities of this sensing concept to assess pressure in biomedical and biomechanical app...
Interrogation Sensing Scheme Based on a Figure-of-Eight Fiber Loop Mirror
Silva, Ricardo M.; Layeghi, A.; Zibaii, M. I.; Latifi, Hamid; Santos, Jose Luis; Lobo Ribeiro, Antonio B.; Frazao, OrlandoA fiber optic interrogation sensor scheme based on a “figure-of-eight” configuration created from a single directional 3 × 3 fiber optic coupler is proposed. Two loops are formed in each arm and one of them contains the sensing head and the other is used as reference signal. A theoretical study based on Jones matrix analysis of this fiber loop mirror combination is reported. The optical configuration is tested ...
A simple, self-referenced, intensity-based optical fibre sensor for temperature...
Silva, Ricardo M.; Baptista, J.M.; Santos, J.L.; Lobo Ribeiro, Antonio B.; Araújo, F.M.; Ferreira, L.A.; Frazão, O.A sensing configuration based on an intensity optical fibre sensor for temperature measurement is reported. Two sensing heads, with identical geometrical configuration, connected in series are implemented. Each sensing head is placed between two fibre Bragg gratings (FBGs), being able to provide a self-referenced measurement, and thus eliminate errors that may arise from undesired intensity fluctuations in the ...
Algorithm for Excitation Optimization of Fabry–Pérot Filters Used in Swept Sources
Avanaki, Mohammad R. N.; Bradu, Adrian; Trifanov, Irina; Lobo Ribeiro, Antonio B.; Hojjatoleslami, Ali; Podoleanu, A. G.We investigate the improvement in the nonlinearity of a conventional wavelength swept laser source on the basis of a fiber Fabry-Pérot tunable filter using a well-established optimization method, simulated annealing (SA). The signal driving the filter is constructed from many short ramps of different slopes that are interconnected. The values of the slopes are optimized through the SA algorithm to achieve maxim...
Optical Current Sensors for High Power Systems: A Review
Silva, Ricardo M.; Martins, Hugo; Nascimento, Ivo; Baptista, José M.; Lobo Ribeiro, Antonio B.; Santos, José L.; Jorge, Pedro; Frazão, OrlandoThe intrinsic advantages of optical sensor technology are very appealing for high voltage applications and can become a valuable asset in a new generation of smart grids. In this paper the authors present a review of optical sensors technologies for electrical current metering in high voltage applications. A brief historical overview is given together with a more detailed focus on recent developments. Technolog...
Temperature-independent torsion sensor based on “figure-of-eight” fiber loop mi...
Silva, Ricardo M.; Lobo Ribeiro, Antonio B.; Frazão, OrlandoAn interrogation sensor system combining the “figure-of-eight” fiber loop mirror using a single directional 3×3 fiber optic coupler was proposed. One fiber loop mirror was formed by inserting a length of high birefringent optical fiber at the input ports of the 3×3 coupler. Splicing the output ports of the 3×3 coupler between them created the other fiber loop mirror. The introduction of this second loop gave ri...
Suspended-core fibers for sensing applications
Frazão, Orlando; Silva, Ricardo M.; Ferreira, Marta S.; Santos, José L.; Lobo Ribeiro, Antonio B.A brief review on suspended-core fibers for sensing applications is presented. A historical overview over the previous ten years about this special designed microstructure optical fiber is described. This fiber presents attractive optical properties for chemical/biological or gas measurement, but it can be further explored for alternative sensing solutions, namely, in-fiber interferometers based on the suspende...