Mr. Stanislav Hejduk Profile

Stanislav Hejduk

Staff at VŠB-Technical Univ of Ostrava

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Author

Publications (16)

Proceedings Article | 14 May 2018 Paper

Sensor system based on the Mach-Zehnder interferometer for the rail transport

Jan Nedoma, Marcel Fajkus, Radek Martinek, Karel Witas, Pavel Mec, Jan Jargus, Stanislav Hejduk, Petr Zavodny, Vladimir Vasinek

Proceedings Volume 10654, 106541G (2018) https://doi.org/10.1117/12.2304582

KEYWORDS: Sensors, Mach-Zehnder interferometers, Interferometry, Optical fibers, Interferometers, Fiber optics, Signal processing, Indium gallium arsenide, Telecommunications

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Proceedings Article | 14 May 2018 Paper

Analysis of transmission properties of optical couplers made from the polydimethylsiloxane (PDMS)

M. Novak, J. Jargus, Pavel Mec, S. Hejduk, V. Vasinek, R. Martinek, J. Vanus

Proceedings Volume 10654, 106541I (2018) https://doi.org/10.1117/12.2304870

KEYWORDS: Optics manufacturing, Optical fibers, Refractive index, Polymers, Thermography, Optical testing, Temperature metrology, Microfluidics, Analytical research, Biomedical optics

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Proceedings Article | 23 December 2016 Paper

Fibre optic portable rail vehicle detector

Stanislav Kepak, Jakub Cubik, Petr Zavodny, Stanislav Hejduk, Jan Nedoma, Alan Davidson, Vladimir Vasinek

Proceedings Volume 10142, 101421M (2016) https://doi.org/10.1117/12.2257061

KEYWORDS: Sensors, Fiber optics, Fiber optics sensors, Interferometers, Demodulation, Safety, Electromagnetic coupling, Cameras, Tablets, Interfaces

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Proceedings Article | 19 September 2016 Paper

Testing FSO WDM communication system in simulation software optiwave OptiSystem in different atmospheric environments

Ales Vanderka, Lukas Hajek, Lukas Bednarek, Jan Latal, Jan Vitasek, Stanislav Hejduk, Vladimir Vasinek

Proceedings Volume 9979, 997914 (2016) https://doi.org/10.1117/12.2237903

KEYWORDS: Free space optics, Wavelength division multiplexing, Modulation, Signal to noise ratio, Telecommunications, Quadrature amplitude modulation, Signal attenuation, Phase shift keying, Head, Eye

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Proceedings Article | 4 September 2015 Paper

Testing resistance modulation formats for FSO communication in turbulent environment, with used simulation box

Ales Vanderka, Lukas Hajek, Jan Latal, Jan Vitasek, Stanislav Hejduk, Vladimir Vasinek

Proceedings Volume 9614, 96140S (2015) https://doi.org/10.1117/12.2180335

KEYWORDS: Eye, Modulation, Fiber optic gyroscopes, Free space optics, Signal attenuation, Fluctuations and noise, Phase shift keying, Receivers, Semiconductor lasers, Atmospheric modeling

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Proceedings Article | 29 July 2015 Paper

Measurement of turbulences influence on the laser beam polarization state

Jan Latal, Jan Vitasek, Lukas Hajek, Petr Koudelka, Petr Siska, Stanislav Hejduk, Ales Vanderka, Vladimir Vasinek

Proceedings Volume 9659, 96591L (2015) https://doi.org/10.1117/12.2196261

KEYWORDS: Polarization, Turbulence, Free space optics, Polarimetry, Optical spheres, Optical simulations, Networks, Atmospheric optics, Thermography, Jones vectors

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Proceedings Article | 6 January 2015 Paper

Influence of DFB laser light on spectral properties of LDs and LEDs

Vladimír Vasinek, Petr Siska, Andrej Liner, Karel Witas, Stanislav Hejduk

Proceedings Volume 9450, 94501H (2015) https://doi.org/10.1117/12.2070588

KEYWORDS: Tunable lasers, Semiconductor lasers, Light emitting diodes, Light sources, Light, Fiber optics, Switches, Modes of laser operation, Optical pumping, Optical isolators

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Proceedings Article | 6 January 2015 Paper

New approach to design of optical transmitter for indoor free space optical network

Jan Latal, Petr Koudelka, Jan Vitasek, Lukas Hajek, Stanislav Hejduk, Andrej Liner, Petr Siska, Vladimir Vasinek

Proceedings Volume 9450, 94501D (2015) https://doi.org/10.1117/12.2073495

KEYWORDS: Free space optics, Transmitters, Adaptive optics, Optical design, Telecommunications, Free space, Optical networks, Light emitting diodes, Free space optical communications, Geometrical optics

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Proceedings Article | 3 May 2013 Paper

Low noise omnidirectional optical receiver for the mobile FSO networks

Karel Witas, Stanislav Hejduk, Vladimir Vasinek, Jan Vitasek, Jan Latal

Proceedings Volume 8774, 87741Q (2013) https://doi.org/10.1117/12.2017086

KEYWORDS: Receivers, Photodiodes, Free space optics, Transmitters, Signal to noise ratio, Geometrical optics, Diodes, Sensors, Optical amplifiers, Amplifiers

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Proceedings Article | 3 May 2013 Paper

Rock massif temperature changes measurement with regard to thermal responses generated by a thermal response test device

Jan Latal, Jan Vitasek, Petr Koudelka, Petr Siska, Andrej Liner, Martin Papes, Karel Witas, Stanislav Hejduk, Vladimir Vasinek

Proceedings Volume 8774, 877416 (2013) https://doi.org/10.1117/12.2017241

KEYWORDS: Temperature metrology, Raman scattering, Optical fibers, Raman spectroscopy, Sensors, Scattering, 3D metrology, Wind energy, Thermal effects, Light scattering

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Proceedings Article | 18 December 2012 Paper

The fog influence on bit error ratio

Jan Vitasek, Jan Látal, Vladimir Vašinek, Stanislav Hejduk, Andrej Liner, Martin Papes, Petr Koudelka, Artem Ganiyev

Proceedings Volume 8697, 86970L (2012) https://doi.org/10.1117/12.2001748

KEYWORDS: Fiber optic gyroscopes, Signal attenuation, Free space optics, Atmospheric modeling, Light emitting diodes, Visibility through fog, Visibility, Diodes, Photodetectors, Meteorology

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Proceedings Article | 19 October 2012 Paper

Simulation of fog influence on laser beam distribution in atmosphere

Vladimir Vasinek, Jan Latal, Petr Koudelka, Jan Vitasek, Karel Witas, Stanislav Hejduk

Proceedings Volume 8540, 85400Y (2012) https://doi.org/10.1117/12.977617

KEYWORDS: Fiber optic gyroscopes, Signal attenuation, Free space optics, Atmospheric optics, Atmospheric propagation, Atmospheric modeling, Gaussian beams, Optical simulations, Telecommunications, Transmittance

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Optical fibreless data networks P2P offer fast data transmissions with big transmittance from 1- 10 Gbps on a distance of 1- 6 km. Perfections of such networks are especially flexibility, rapid creation of communications. Sensitivity to atmospheric influences, necessity of light on sight belongs to disadvantages. Transmission through atmosphere be characterized by non-stationarity, inhomogeneity, the influences have random character. It means immediately that it is possible only with difficulty to project conclusions concerning to the measurement on one line upon fiberless line in another position. Contribution tackles a question of forming of the artificial hazy atmospheres, finding the statistical parameters of artificially created foggy atmospheres that could be reproduced to real environment. This work describes created laboratory apparatus powered with fog generator, heat source and ventilating fans, which allow in a controlled way to change the optical transmission inside the bounded space. Laser diode radiation at wavelength of 850 nm is transmitted into created space like this which is scanned with optical power meter after passing of artificially created turbulent vaporous environment. Changes in intensity of the passed lights are captured; the mean value and maximum deviation from the mean value are computed. In this way it is possible to change the reached specific attenuation in dB/km. Owing to turbulences it happens to deviations from the mean value, these abnormalities are characterized by the distribution function that describes the size of turbulences in time. By the help of ergodic theorem then it is possible to deduce that the distribution function of the foggy turbulences gained at continuous time evaluation has same history like the distribution function gained behind the same conditions in the setup in other times. It holds as well that these distribution functions are the same for variety of points in experimental space, provided there are well - kept the same conditions of turbulence creations. Contribution shows the experimental values, shapes of distribution functions, their influence on attenuation of fiberless communication lines and on achieved the transmission BER. At the present time the verification of conclusions is performed from the experimental model on outdoor connecting link working upon the distance of 1,3 km at the transmission rate of 1,25 Gbps.

Proceedings Article | 2 May 2012 Paper

Spectral characteristics of fiber couplers for FTTx networks

Jan Vitasek, Jan Latal, Petr Koudelka, Vladimir Vasinek, Jiri Bocheza, Stanislav Hejduk

Proceedings Volume 8436, 843614 (2012) https://doi.org/10.1117/12.922003

KEYWORDS: Fiber couplers, Manufacturing, Light sources, Fiber to the x, Telecommunications, Spectroscopy, Wavelength division multiplexing, Optical networks, Optical fibers, Chromium

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Proceedings Article | 6 October 2011 Paper

Interference fiber ring perimeter with FFT analysis

Vladimir Vasinek, Jan Vitasek, Stanislav Hejduk, Jiri Bocheza, Jan Latal, Petr Koudelka

Proceedings Volume 8186, 81860P (2011) https://doi.org/10.1117/12.898076

KEYWORDS: Interferometers, Signal processing, Phase modulation, Mach-Zehnder interferometers, Interferometry, Optical fibers, Fourier transforms, Motion analysis, Single mode fibers, Photodetectors

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Fiber optical interferometers belong to highly sensitive equipments that are able to measure slight changes like distortion of shape, temperature and electric field variation and etc. Their great advantage is that they are insensitive on ageing component, from which they are composed of. It is in virtue of herewith, that there are evaluated no changes in optical signal intensity but number interference fringes. To monitor the movement of persons, eventually to analyze the changes in state of motion we developed method based on analysis the dynamic changes in interferometric pattern. We have used Mach- Zehnder interferometer with conventional SM and PM fibers excited with the DFB laser at wavelength of 1550 nm. It was terminated with optical receiver containing InGaAs PIN photodiode. Its output was brought into measuring card module that performs on FFT of the received interferometer signal. The signal rises with the composition of two waves passing through single interferometer arm. The optical fiber SMF 28e or PM PANDA fiber in one arm is referential; the second one is positioned on measuring slab at dimensions of 1×2m. A movement of persons over the slab was monitored, signal processed with FFT and frequency spectra were evaluated. They rose owing to dynamic changes of interferometric pattern. The results reflect that the individual subjects passing through slab embody characteristic frequency spectra, which are individual for particular persons. The scope of measuring frequencies proceeded from zero to 10 kHz. At experiments the stability of interferometric patterns was evaluated as from time aspects, so from the view of repeated identical experiments. Two kinds of balls (tennis and ping-pong) were used to plot the repeatability measurements and the gained spectra at repeated drops of balls were compared. Those stroked upon the same place and from the same elevation and dispersion of the obtained frequency spectra was evaluated. These experiments were performed on the series of 20 repeated drops from highs of 0,5 and 1m. The evaluation of experiments displayed that the dispersion of measured values is lower than 4% and could be reduced by PM fibers usage.

Proceedings Article | 23 September 2011 Paper

Polyaniline nanofilms as a base for novel optical sensor structures

Vladimir Vasinek, Jiri Bocheza, Stanislav Hejduk, Jan Latal, Petr Koudelka, Jan Vitasek

Proceedings Volume 8102, 81020H (2011) https://doi.org/10.1117/12.893085

KEYWORDS: Transmittance, Glasses, Ocean optics, Optical fibers, Sensors, Connectors, Temperature metrology, Fiber optics sensors, Telecommunications, Optical sensors

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Proceedings Article | 9 May 2011 Paper

Fiber optic DTS system application in the research of accumulation possibilities of thermal energy in the rock mass

Jan Látal, Petr Koudelka, Petr Šiška, Jan Skapa, František Hanáečk, Vladimír Vašinek, Jan Vitásek, Stanislav Hejduk, Jiří Bocheza

Proceedings Volume 8073, 80731T (2011) https://doi.org/10.1117/12.887082

KEYWORDS: Temperature metrology, Fiber optics, Sensors, Raman scattering, Optical fibers, Temperature sensors, Optical sensors, Vestigial sideband modulation, Molecules, Electrical engineering

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Showing 5 of 16 publications

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