Contents
2013
Volume: 3 Issue 1
10 Article(s)
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Experimental and Theoretical Analysis of an Optical Current Sensor for High Power Systems
A. C. S. BRIGIDA, I. M. NASCIMENTO, S. MENDONCA, J. C. W. A. COSTA... and P. A. S. JORGE|Show fewer author(s)
A magneto-optical sensor, using a dual quadrature polarimetric processing scheme, was evaluated for current metering and protection applications in high voltage lines. Sensor calibration and resolution were obtained in different operational conditions using illumination in the 1550-nm band. Results obtained indicated tA magneto-optical sensor, using a dual quadrature polarimetric processing scheme, was evaluated for current metering and protection applications in high voltage lines. Sensor calibration and resolution were obtained in different operational conditions using illumination in the 1550-nm band. Results obtained indicated the feasibility of interrogating such sensor via the optical ground wire (OPGW) link installed in standard high power grids. The polarimetric bulk optical current sensor also was theoretically studied, and the effects of different sources of error considering practical deployment were evaluated. In particular, the interference from external magnetic fields in a tree-phase system was analyzed..
Photonic Sensors
- Publication Date: Apr. 16, 2013
- Vol. 3, Issue 1, 26 (2013)
Numerical Study on Spectral Domain Optical Coherence Tomography Spectral Calibration and Re-Sampling Importance
Hamid HOSSEINY, and Carla CARMELO ROSA
A spectral calibration technique, a data processing method and the importance of calibration and re-sampling methods for the spectral domain optical coherence tomography system were numerically studied, targeted to optical coherence tomography (OCT) signal processing implementation under graphics processing unit (GPU) A spectral calibration technique, a data processing method and the importance of calibration and re-sampling methods for the spectral domain optical coherence tomography system were numerically studied, targeted to optical coherence tomography (OCT) signal processing implementation under graphics processing unit (GPU) architecture. Accurately, assigning the wavelength to each pixel of the detector is of paramount importance to obtain high quality images and increase signal to noise ratio (SNR). High quality imaging can be achieved by proper calibration methods, here performed by phase calibration and interpolation. SNR was assessed employing two approaches, single spectrum moving window averaging and consecutive spectra data averaging, to investigate the optimized method and factor for background noise reduction. It was demonstrated that the consecutive spectra averaging had better SNR performance..
Photonic Sensors
- Publication Date: Apr. 16, 2013
- Vol. 3, Issue 1, 35 (2013)
Fiber Laser Sensor Based on a Phase-Shifted Chirped Grating for Acoustic Sensing of Partial Discharges
Sanderson E. U. LIMA, Rubem G. FARIAS, Francisco M. ARAúJO, Luís A. FERREIRA... and Orlando FRAZAO|Show fewer author(s)
Acoustic emission monitoring is often used in the diagnosis of electrical and mechanical incipient faults in the high voltage apparatus. Partial discharges are a major source of insulation failure in electric power transformers, and the differentiation from other sources of acoustic emission is of the utmost importanceAcoustic emission monitoring is often used in the diagnosis of electrical and mechanical incipient faults in the high voltage apparatus. Partial discharges are a major source of insulation failure in electric power transformers, and the differentiation from other sources of acoustic emission is of the utmost importance. This paper reports the development of a new sensor concept-a fiber laser sensor based on a phase-shifted chirped fiber grating-for the acoustic emission detection of incipient faults in oil-filled power transformers. These sensors can be placed in the inner surface of the transformer tank wall, not affecting the insulation integrity of the structure and improving fault detection and location. The performance of the sensing head is characterized and compared for different surrounding media: air, water, and oil. The results obtained indicate the feasibility of this sensing approach for the industrial development of practical solutions..
Photonic Sensors
- Publication Date: Apr. 16, 2013
- Vol. 3, Issue 1, 44 (2013)
Temperature-Independent Torsion Sensor Based on “Figure-of-Eight” Fiber Loop Mirror
Ricardo M. SILVA, António B. Lobo RIBEIRO, and Orlando FRAZAO
An 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&An 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 rise to two polarization states of light with the same frequency but different optical phase. The mechanical torsion sensing head was located at the second loop and was exhibited an average modulus torsion sensitivity of 7.9×10-4 degree/dB. The performance of the sensor was not affected by environmental temperature variations..
Photonic Sensors
- Publication Date: Apr. 16, 2013
- Vol. 3, Issue 1, 52 (2013)
Computational Models for New Fiber Optic Tweezers
R. S. RODRIGUES RIBEIRO, P. A. S. JORGE, and A. GUERREIRO
This paper discusses the calculation of the trapping forces in optical tweezers using a combination of the finite differences time domain (FDTD) method and the Lorentz force on electric dipoles. The results of 2D simulations of the trapping of a circular particle by a waveguide with a circular tip are presented and disThis paper discusses the calculation of the trapping forces in optical tweezers using a combination of the finite differences time domain (FDTD) method and the Lorentz force on electric dipoles. The results of 2D simulations of the trapping of a circular particle by a waveguide with a circular tip are presented and discussed..
Photonic Sensors
- Publication Date: Apr. 16, 2013
- Vol. 3, Issue 1, 57 (2013)
Numerical Investigation of a Refractive Index SPR D-Type Optical Fiber Sensor Using COMSOL Multiphysics
D. F. SANTOS, A. GUERREIRO, and J. M. BAPTISTA
Recently, many programs have been developed for simulation or analysis of the different parameters of light propagation in optical fibers, either for sensing or for communication purposes. In this paper, it is shown the COMSOL Multiphysics as a fairly robust and simple program, due to the existence of a graphical envirRecently, many programs have been developed for simulation or analysis of the different parameters of light propagation in optical fibers, either for sensing or for communication purposes. In this paper, it is shown the COMSOL Multiphysics as a fairly robust and simple program, due to the existence of a graphical environment, to perform simulations with good accuracy. Results are compared with other simulation analysis, focusing on the surface plasmon resonance (SPR) phenomena for refractive index sensing in a D-type optical fiber, where the characteristics of the material layers, in terms of the type and thickness, and the residual fiber cladding thickness are optimized..
Photonic Sensors
- Publication Date: Apr. 16, 2013
- Vol. 3, Issue 1, 61 (2013)
Modeling Refractive Index Change in Writing Long-Period Fiber Gratings Using Mid-Infrared Laser Radiation
Joao M. P. COELHO, Marta C. NESPEREIRA, Manuel ABREU, and José M. REBORDAO
The research on the use of fiber sensors based on long-period fiber gratings inscribed by CO2 laser mid-infrared radiation has increased in the last years. In this paper, a set of analytical expressions are used to model the interaction between laser radiation and an optical fiber and to determine the resulting refractThe research on the use of fiber sensors based on long-period fiber gratings inscribed by CO2 laser mid-infrared radiation has increased in the last years. In this paper, a set of analytical expressions are used to model the interaction between laser radiation and an optical fiber and to determine the resulting refractive index change. Thermal and residual stress analysis is exemplified for a standard single mode fiber, demonstrating the capability of these models to point out the necessary parameters to achieve proper optical fiber devices based on long period fiber gratings. Experimental results are also presented..
Photonic Sensors
- Publication Date: Apr. 16, 2013
- Vol. 3, Issue 1, 67 (2013)
New Approach to the Strain Analysis of Bragg Grating Sensors
José R. Alves da CUNHA, Petrus Alcantara JR., Angela Santa BRíGIDA, Gilvan BORGES, and Joao Weyl COSTA
The response of an optical strain sensor based on the fiber Bragg grating is theoretically analyzed with a different approach of that found usually in the literature. In this model, geometrical changes suffered by the grating itself are taken into account. The results are compared with those from experiments, showing vThe response of an optical strain sensor based on the fiber Bragg grating is theoretically analyzed with a different approach of that found usually in the literature. In this model, geometrical changes suffered by the grating itself are taken into account. The results are compared with those from experiments, showing very good agreement..
Photonic Sensors
- Publication Date: Apr. 16, 2013
- Vol. 3, Issue 1, 74 (2013)
Review
Advances and New Applications Using the Acousto-Optic Effect in Optical Fibers
Alexandre A. P. POHL, Roberson A. OLIVEIRA, Ricardo E. DA SILVA, Carlos A. F. MARQUES... and Rogério N. NOGUEIRA|Show fewer author(s)
This work presents a short review of the current research on the acousto-optic mechanism applied to optical fibers. The role of the piezoelectric element and the acousto-optic modulator in the excitation of flexural and longitudinal acoustic modes in the frequency range up to 1.2 MHz is highlighted. A combination of thThis work presents a short review of the current research on the acousto-optic mechanism applied to optical fibers. The role of the piezoelectric element and the acousto-optic modulator in the excitation of flexural and longitudinal acoustic modes in the frequency range up to 1.2 MHz is highlighted. A combination of the finite elements and the transfer matrix methods is used to simulate the interaction of the waves with Bragg and long period gratings. Results show a very good agreement with experimental data. Recent applications such as the writing of gratings under the acoustic excitation and a novel viscometer sensor based on the acousto-optic mechanism are discussed..
Photonic Sensors
- Publication Date: Apr. 16, 2013
- Vol. 3, Issue 1, 1 (2013)
Fabrication of Tailored Bragg Gratings by the Phase Mask Dithering/Moving Technique
Miguel MELO, and Paulo V. S. MARQUES
The most relevant aspects related to the phase mask dithering/moving method for the fabrication of complex Bragg grating designs are reviewed. Details for experimental implementation of this technique is presented, including theoretical analysis of the calibration functions for the correct dither/displacement. Results The most relevant aspects related to the phase mask dithering/moving method for the fabrication of complex Bragg grating designs are reviewed. Details for experimental implementation of this technique is presented, including theoretical analysis of the calibration functions for the correct dither/displacement. Results from tailored Bragg grating structures fabricated by this method are shown. Apodized Bragg gratings with modeled spatial profiles were implemented, resulting in side mode suppression levels of more than 20 dB in gratings showing transmission filtering level higher than 30 dB. Chirped gratings with the spectral bandwidth up to 4 nm, π-shift and sampled Bragg gratings with equalized peaks equally spaced by 0.8 nm (100 GHz) were also fabricated..
Photonic Sensors
- Publication Date: Apr. 16, 2013
- Vol. 3, Issue 1, 81 (2013)
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