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Zrenjanin, Serbia

Manojlovic L.M.,Zrenjanin Technical College
Applied Optics | Year: 2011

A quantitative theoretical analysis of the quadrant photodetector (QPD) sensitivity in position measurement is presented. The Gaussian light spot irradiance distribution on the QPD surface was assumed to meet most of the real-life applications of this sensor. As the result of the mathematical treatment of the problem, we obtained, in a closed form, the sensitivity function versus the ratio of the light spot 1/e radius and the QPD radius. The obtained result is valid for the full range of the ratios. To check the influence of the finite light spot radius on the interaxis cross talk and linearity, we also performed a mathematical analysis to quantitatively measure these types of errors. An optimal range of the ratio of light spot radius and QPD radius has been found to simultaneously achieve low interaxis cross talk and high linearity of the sensor. © 2011 Optical Society of America. Source


Manojlovic L.M.,Zrenjanin Technical College
Applied Optics | Year: 2014

A novel high-resolution wide-dynamic range electronically scanned white-light interferometry-based interrogation technique is presented. By using off-the-shelf optical components, this technique is capable of reaching a subnanometer resolution. The technique relies on a simple optical setup in which the wedge and camera axes are mutually inclined for a very small angle in the horizontal plane and two-dimensional fringe pattern analysis. Resolution below 0.3 nm and dynamic range of 106 dB have been achieved with a signal-to-noise ratio lower than 25 dB. © 2014 Optical Society of America. Source


Manojlovic L.M.,Zrenjanin Technical College
IEEE Sensors Journal | Year: 2011

A novel common path demodulation technique for low-coherence fiber-optic sensors for vibration measurement based on two serially connected fused silica fiber-optic directional couplers is presented. A 2 × 2 coupler is used in the sensor arm and a 3 × 3 coupler serves as a receiving interferometer, providing at the same time two quadrature signals for the interferometric demodulation. A very stable output signal is obtained after the differentiate-and-cross-multiply procedure with the minimal detectable amplitude of the vibration of about 70 pm/√Hz. © 2010 IEEE. Source


Manojlovic L.M.,Zrenjanin Technical College
IEEE Journal of Quantum Electronics | Year: 2011

A novel method for optical coherence tomography (OCT) resolution enhancement is presented. A simple mathematical analysis is given where, as a final result, the high-resolution image of an object axial structure is obtained. The object axial structure has been found to be proportional to the inverse Fourier transform of the ratio of two optical power spectra, i.e., the high-frequency part of the channeled spectrum at the interferometer output and the white-light source spectrum, respectively. An experimental setup, based on a very simple fiber-optic interferometric sensing unit, has been built in order to verify the result of the given mathematical model. Compared to the standard Fourier domain OCT, a sevenfold enhancement of the axial resolution is obtained. By using inexpensive and commercially available equipment, the resolution of about 1.3 μm is obtained. © 2006 IEEE. Source


Manojlovic L.M.,Zrenjanin Technical College
Optical Fiber Technology | Year: 2016

A crosstalk analysis of the in-line quasi-distributed low-coherence low-finesse Fabry-Pérot fiber-optic interferometric sensors is presented in this paper. The appropriate selection of the sensor cavity lengths eliminates the presence of the second-order intermodulations. Therefore, the intermodulations that can significantly influence the sensors crosstalk are the third-order intermodulations. For a typical sensor configuration by choosing the in-fiber mirror reflection coefficient lower than 0.5%, the minimum achievable signal-to-intermodulation ratio is higher than 26 dB for a maximal possible number of sensor placed along the fiber that satisfies broad range of requirements for most of the quasi-distributed measurements of typical parameters such as strain and temperature. © 2016 Elsevier Inc. All rights reserved. Source

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