Lidé

Ing. Michal Lucki, Ph.D.

Všechny publikace

Experimental load test statistics for the selected IPS tools on low-performance IoT devices

  • DOI: 10.2478/jee-2019-0058
  • Odkaz: https://doi.org/10.2478/jee-2019-0058
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The goal of this paper is to propose a testing procedure for selected Intrusion Prevention Systems (IPS) in a realistic network traffic in terms of their suitability on a given hardware microcomputers for low-performance devices for Internet ofThings (IoT). We perform an IPS research in terms of resource usage in order to establish a universal procedure of checking,whether a given microcomputer controlling IoT devices (often in overloaded state) can additionally burden the installation and start-up of IPS. The experiment is repeated on several boards under overload condition to determine the maximum data rate, above which transmission degrades. The presented testing method is an exemplary tool for IoT applications concerning the security of embedded devices with low performance.

Optical splitter design for telecommunication access networks with tripple-play services

  • Autoři: Agalliu, R., Burtscher, C., Ing. Michal Lucki, Ph.D., Seyringer, D.
  • Publikace: Journal of Electrical Engineering. 2018, 69(1), 32-38. ISSN 1335-3632.
  • Rok: 2018
  • DOI: 10.1515/jee-2018-0004
  • Odkaz: https://doi.org/10.1515/jee-2018-0004
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    In this paper, we present various designs of optical splitters for access networks, such as GPON and XG-PON by ITU-T with triple-play services (i.e. data, voice and video). The presented designs exhibit a step forward, compared to the solutions recommended by the ITU, in terms of performance in transmission systems using WDM. The quality of performance is represented by the bit error rate and the Q-factor. Besides the splitter, we propose a new length-optimized splitter design with a smaller waveguide core, providing some reduction of non-uniformity of the power split between the output waveguides. The achieved splitting parameters are incorporated in the simulations of passive optical networks. For this purpose, the OptSim tool employing Time Domain Split Step method was used.

Waveguide Shape Modelling and Optimization for High Channel Y-Branch Splitter in Optical Transmission Systems

  • Autoři: Burtscher, C., Ing. Michal Lucki, Ph.D., Seyringer, D.
  • Publikace: 20th International Conference on Transparent Optical Networks. New Jersey: IEEE, 2018. ISSN 2162-7339. ISBN 9781538666043.
  • Rok: 2018
  • DOI: 10.1109/ICTON.2018.8473871
  • Odkaz: https://doi.org/10.1109/ICTON.2018.8473871
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The goal of this paper is to model and to optimize a new Y-branch waveguide shape. For this purpose, we used a new Y-branch shape for 1×32 Y-branch splitter possessing better splitting properties, i.e. lower insertion loss, background noise or non-uniformity, compared to a conventional Y-branch splitter used in access networks, such as GPON and XG-PON by ITU-T. By optimizing this structure, the splitting properties could be improved by more than twice.

Comparision of splitting properties of various 1×16 splitters

  • Autoři: Burtscher, C., Seyringer, D., Ing. Michal Lucki, Ph.D.,
  • Publikace: Advances in Electrical and Electronic Engineering. 2017, 1(15), 107-113. ISSN 1336-1376.
  • Rok: 2017
  • DOI: 10.15598/aeee.v15i1.2014
  • Odkaz: https://doi.org/10.15598/aeee.v15i1.2014
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Optical Access Networks (OAN) mostly use optical splitters to distribute the services from Optical Line Terminal (OLT) on the provider's side to the subscribers in Optical Network Unit (ONU). Optical splitters are the key components in such access networks as for example GPON and XG-PON by ITU-T. In this paper we investigate the optical properties of 1 x 16 Y-branch splitter and 1 x 16 MMI splitters based on different widths of multimode interference section and different lengths of the output ports. These two splitters were designed, simulated and the obtained results of both were studied and compared with each other. Additionally, we show that the used standard waveguide core size (usually 6 x 6 mu m(2) to match the diameter of the single mode input/output fibers, i.e. to keep the coupling loses as low as possible) supports not only propagation of the single mode but of the first mode too, leading to an asymmetric splitting ratio (increasing non-uniformity of split power over all the output waveguides). Decreasing waveguide core size, it is possible to suppress presence of the first mode and this way to reduce non-uniformity.

Design and simulation of 1x32 Y-branch splitter applying different photonics tools

  • Autoři: Burtscher, C., Seyringer, D., Ing. Michal Lucki, Ph.D., Kuzma, A.
  • Publikace: Proceedings of of the 23rd International conference on applied physics of condensed matter. Bratislava: FEI, Slovak University of Technology, 2017. ISBN 9788022746991.
  • Rok: 2017
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This paper aims to design, simulate and optimize low loss 1x32 Y-branch splitter applying two different photonics tools based on the Beam Propagation Method. Initially, a standard 1x32 Y-branch splitter is designed and simulated in 2D with OptiBPM photonics tool from Optiwave System Inc. We will show that optimizing this standard structure the asymmetric splitting ratio of the optical signal can be suppressed to one third of the original value. This optimized low loss structure was then designed and simulated in 3D with RSoft photonics tool from Synopsys Inc

Modeling and optimization of 1 × 32 Y-branch splitter for optical transmission systems

  • Autoři: Burtscher, C., Seyringer, D., Kuzma, A., Ing. Michal Lucki, Ph.D.,
  • Publikace: Optical and Quantum Electronics. 2017, 49(12), 1-12. ISSN 0306-8919.
  • Rok: 2017
  • DOI: 10.1007/s11082-017-1228-8
  • Odkaz: https://doi.org/10.1007/s11082-017-1228-8
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The goal of this paper is to design a low-loss 1 × 32 Y-branch optical splitter for optical transmission systems, using two different design tools employing Beam Propagation Method. As a first step, a conventional 1 × 32 Y-branch splitter was designed and simulated in two-dimensional environment of OptiBPM photonic tool. The simulated optical properties feature high loss, high asymmetric splitting ratio and a large size of the designed structure, too. In the second step of this work we propose an optimization of the conventional splitter design leading to suppression of the asymmetric splitting ratio to one-third of its initial value and to the improvement of the losses by nearly 2 dB. In addition, 50% size reduction of the designed structure was also achieved. This length-optimized low-loss splitter was then modelled in a three-dimensional environment of RSoft photonic tool and the simulated results confirm the strong improvement of the optical properties.

New waveguide shape for low loss and high uniformity Y-branch optical splitter

  • Autoři: Burtscher, C., Seyringer, D., Ing. Michal Lucki, Ph.D., Kohler, L.
  • Publikace: Integrated Optics: Devices, Materials, and Technologies XXI 2017. Washington: SPIE - The International Society for Optical Engineering, 2017. vol. 10106. ISSN 0277-786X. ISBN 978-1-5106-0653-1.
  • Rok: 2017
  • DOI: 10.1117/12.2249758
  • Odkaz: https://doi.org/10.1117/12.2249758
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    In this paper a new Y-branch shape is proposed for 1x32 Y-branch splitter ensuring better splitting properties compared to the one recommended by ITU, in terms of their performance in transmission systems using wavelength division multiplexing.

Transmission Transparency and Potential Convergence of Optical Network Solutions at the Physical Layer for Bit Rates from 2.5 Gbps to 256 Gbps

  • Autoři: Agalliu, R., Ing. Michal Lucki, Ph.D.,
  • Publikace: Advances in Electrical and Electronic Engineering. 2017, Vol. 15(No. 5), 877-884. ISSN 1336-1376.
  • Rok: 2017
  • DOI: 10.15598/aeee.v15i5.2502
  • Odkaz: https://doi.org/10.15598/aeee.v15i5.2502
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    In this paper, we investigate optical network recommendations GPON and XG-PON with triple-play services in terms of physical reach, number of subscribers, transceiver design, modulation format and implementation cost. Despite trends to increase the bit rate from 2.5 Gbps to 10 Gbps and beyond, TDM-PONs cannot cope with bandwidth requirements of future networks. TDM and WDM techniques can be combined, resulting in improved scalability. Longer physical reach can be achieved by deploying active network elements within the transmission path. We investigate these options by considering their potential coexistence at the physical layer. Subsequently, we analyse the upgrade of optical channels to 100 Gbps and 256 Gbps by using advanced modulation formats, which combine polarization division multiplexing with coherent detection and digital signal processing. We show that PDM-QPSK format is suitable for 100 Gbps systems and PDM-16QAM is more beneficial at 256 Gbps. Simulations are performed in the OptSim software environment.

Manufacturing of membranes by laser ablation in SiC, sapphire, glass and ceramic for GaN/ferroelectric thin film MEMS and pressure sensors

  • Autoři: Zehetner, J., Kraus, S., Ing. Michal Lucki, Ph.D., Vanko, G., Dzuba, J., Lalinsky, T.
  • Publikace: Microsystem Technologies. 2016, 22(7), 1883-1892. ISSN 0946-7076.
  • Rok: 2016
  • DOI: 10.1007/s00542-016-2887-2
  • Odkaz: https://doi.org/10.1007/s00542-016-2887-2
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    AlGaN/GaN-based high electron mobility transistors (HEMTs), Schottky diodes and/or resistors have been presented as sensing devices for mechanical or chemical sensors operating in extreme conditions. The sensitivity of the AlGaN/GaN based MEMS pressure sensor can be modiied by membrane thickness. In case of SiC as substrate material of the epitaxial AlGaN/GaN heterostructure layers, we applied laser ablation technique for micromachining of the membranes. We were able to verify the feasibility of this process by fabrication of micromechanical membrane structures also in bulk 3C-SiC, borosilicate glass, sapphire and Al2O3 ceramic substrates by femtosecond laser (520 nm) ablation. On a 350 µm-thick 4H-SiC substrate we produced an array of 275 µm deep and 1000–3000 µm in diameter blind holes without damaging the 2 µm GaN layer at the back side. Our experiments indicate that pinhole defects in the ablated membranes are affected by ripple structures related to the polarization of the laser. We developed an ablation technique inhibiting the formation of pin holes caused by laser induced periodic surface structures (LIPSS).

MICRO STRUCTURING OF BULK SIC SUBSTRATES BY FEMTOSECOND LASER ABLATION

  • Autoři: Zehetner, J., Vanko, G., Dzuba, J., Ryger, I., Lalinsky, T., Ing. Michal Lucki, Ph.D., Kraus, S.
  • Publikace: Proceedings of the 22 th International conference on APPLIED PHYSICS OF CONDENSED MATTER. Bratislava: FEI, Slovak University of Technology, 2016. ISBN 978-80-227-4373-0.
  • Rok: 2016
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    SiC is a material basis for pressure and strain sensors used in harsh thermal environment conditions. For such sensor devices, piezoelectric III-N compounds, especially gallium nitride (GaN)-related heterostructures on appropriate tailored SiC diaphragms are often used. We demonstrated that diaphragms can be fabricated faster with laser ablation than by reactive ion etching. However, laser ablation frequently causes pinholes in SiC membranes provoking increased risk to damage the III-N heterostructure by the fabrication process. Our experiments confirmed that pinhole defects in the ablated membranes are initiated by ripple structures related to the polarization of the laser. We developed an ablation technique inhibiting the formation of pin holes caused by laser induced periodic surface structures (LIPSS). In addition we tested the hypothesis that LIPSS in SiC act like slot waveguides performing a numerical study of light propagation in LIPSS. The results showed that laser intensity is enhanced inside LIPSS which supports the experimental ablation findings in the formation of pinholes and led us to effective countermeasures.

Study of Splitting Properties of 1x16 Splitter MMI Splitter based on Different Widths of the Multimode Interference Section

  • Autoři: Burtscher, C., Seyringer, D., Ing. Michal Lucki, Ph.D.,
  • Publikace: Advances in Electronic and Photonic Technologies. Žilina: University of Žilina, 2016. ISBN 978-80-554-1226-9.
  • Rok: 2016
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    In this paper, we investigated optical properties of 1x16 splitters based on the MMI approach. We studied the optical properties of the splitter, when the width of the multimode interference section and the length of the output ports were modified.

Study of the Optical Properties of 1x16 Splitter Based on Y-Branch and MMI Approaches

  • Autoři: Burtscher, C., Ing. Michal Lucki, Ph.D., Seyringer, D.
  • Publikace: 18TH INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS (ICTON). New York: IEEE, 2016. pp. 1-4. ISSN 2162-7339. ISBN 978-1-5090-1467-5.
  • Rok: 2016
  • DOI: 10.1109/ICTON.2016.7550642
  • Odkaz: https://doi.org/10.1109/ICTON.2016.7550642
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    In this paper we investigate optical properties of 1x16 splitters based on Y-branch and MMI approaches. These splitters were designed, simulated and the obtained results of both approaches were studies and compared with each other. Additionally, we will show that the used standard waveguide core size (usually 6 x 6 mu m(2) to match the diameter of the single mode input/output fibers, i.e. to keep the coupling loses as low as possible) supports not only propagation of the single mode but of the first mode too, leading to an asymmetric splitting ratio ( increasing non-uniformity of the split power over all the output waveguides). Decreasing waveguide core size it is possible to suppress presence of the first mode and this way to reduce non-uniformity.

System Performance and Limits of Optical Modulation Formats in Dense Wavelength Division Multiplexing Systems

  • Autoři: Agalliu, R., Ing. Michal Lucki, Ph.D.,
  • Publikace: Elektronika ir Elektrotechnika. 2016, 22(2), 123-129. ISSN 1392-1215.
  • Rok: 2016
  • DOI: 10.5755/j01.eie.22.2.9599
  • Odkaz: https://doi.org/10.5755/j01.eie.22.2.9599
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    In this paper we investigate in OptSim software environment the system performance of intensity and phase modulation formats for different network scenarios and dense wavelength division multiplexing grids. OptSim employs the Time Domain Split Step method to implement the signal distribution equation in a fiber. We investigate intensity formats, such as Non Return to Zero, Return to Zero, Carrier-Suppressed Return to Zero and DuoBinary, and phase modulation formats like Differential Phase-Shift Keying and Differential Quadrature Phase-Shift Keying. The main goal is to compare these formats in terms of bit error rate, Q-factor, optical reach and grid limitations for transmission rates 10, 40 and 100 Gbps per channel and discuss the possibilities of increasing their spectral efficiency. We also focus on other advanced solutions such as the polarization division multiplexing combined with phase modulations, coherent detection and advanced digital signal processing which mainly benefits in spectral efficiency, optical signal to noise ratio and chromatic dispersion tolerances.

Comparison of Optical Properties of 1 x 8 Splitters Based on Y-Branch and MMI Approaches

  • Autoři: Burtscher, C., Ing. Michal Lucki, Ph.D., Seyringer, D.
  • Publikace: Romanian Reports in Physics. 2015, 67(4), 1578-1585. ISSN 1221-1451.
  • Rok: 2015
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    1 × 8 Y-branch and MMI splitters were designed, simulated and the obtained results of both approaches were studies and compared with each other for such splitters. The core size of the used waveguides is usually 6 × 6 μm2 to match the diameter of the single mode input/output fibers, i.e. to keep the coupling loses as low as possible. In this work we show that the used waveguide core size supports not only propagation of the single mode but of the first mode too, leading to an asymmetric splitting ratio (increasing non-uniformity of the split power over all the output waveguides). Decreasing waveguide core size it is possible to suppress presence of the first mode and this way to reduce non-uniformity, nearly to one half of the original value.

Comparison of Optical Properties of 1x8 Splitters Based on Y-Branch and MMI Approaches

  • Autoři: Burtscher, C., Ing. Michal Lucki, Ph.D., Seyringer, D.
  • Publikace: Micro- to Nano-Photonics IV- ROMOPTO 2015. Bucarest: Publishing House of the Romanian Academy, 2015.
  • Rok: 2015
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    1x8 Y-branch and MMI splitters were designed, simulated and the obtained results of both approaches were studies and compared with each other for such splitters. The core size of the used waveguides is usually 6 x 6 µm2 to match the diameter of the single mode input/output fibers, i.e. to keep the coupling loses as low as possible. In this work we show that the used waveguide core size supports not only propagation of the single mode but of the first mode too, leading to an asymmetric splitting ratio (increasing non-uniformity of the split power over all the output waveguides). Decreasing waveguide core size it is possible to suppress presence of the first mode and this way to reduce non-uniformity, nearly to one half of the original value.

Design of As2S3-based chalcogenide photonic crystal fibre with large mode area and low bending loss for mid-infrared

  • Autoři: Zelený, R., Ing. Michal Lucki, Ph.D.,
  • Publikace: Proceedings on 17th International Conference on Transparent Optical Networks. Warsaw: National Institute of Telecommunications, 2015. pp. 1-4. ISSN 2162-7339. ISBN 978-1-4673-7880-2.
  • Rok: 2015
  • DOI: 10.1109/ICTON.2015.7193668
  • Odkaz: https://doi.org/10.1109/ICTON.2015.7193668
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    In this paper, an effectively single mode reasonably bendable leakage channel fibre is designed having the highly nonlinear As2S3 chalcogenide glass as the fibre background. The fibre is designed to have effective mode area as large as possible as well as to have low confinement loss in the bent fibre. The fibre modal properties are calculated through the finite difference frequency domain method to investigate supercontinuum generation inside the designed fibre. Using the light pump near the zero dispersion wavelength at 4.9 µm, the supercontinuum is numerically observed as nearly flat and broad from 3 to 8 µm.

Design, Simulation and Optimization of High Channel Optical Splitters

  • Autoři: Burtscher, C., Ing. Michal Lucki, Ph.D., Seyringer, D.
  • Publikace: Advances in Electronic and Photonic Technologies. Žilina: University of Žilina, 2015. pp. 1-6. ISBN 978-80-554-1033-3.
  • Rok: 2015
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The standard low index waveguides, used in the Y-branch optical splitters, have usually size of 6 x 6 µm2 ensuring on one side small coupling loses between fibers and waveguides and on the other side supporting mainly the single mode light propagation. However, in this paper it is shown that the presence of the first mode, which appears in the standard 6 x 6 µm2 waveguide, is already so strong that it causes asymmetric splitting of optical signals. To suppress the presence of the first mode we reduced the waveguide core size which allows improving strongly the splitting parameters of high channel 1x32 and 1x64 Y-branch splitters. Additionally, it was possible to reduce the size of the designed 1x32 Y-branch splitter to the half of its original value and the size of the designed 1x64 Y-branch splitter to nearly one third of its original value.

Dispersion Compensating Fibres for Fibre Optic Telecommunication Systems

  • DOI: 10.5772/59152
  • Odkaz: https://doi.org/10.5772/59152
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Chromatic dispersion (CD) of optical pulses in an optical fibre influences their width. It refers to changes in propagation of particular frequency components contained in optical pulses causing extension of optical pulses. The fibre reach is then significantly limited, unless signal regenerators are used. Because the pulse spread degrades optical systems, it is necessary to prevent its origination or to eliminate its results. CD ought to be suppressed or one shall prevent its origination by specialty optical fibres, including both conventional and microstructured optical fibres (MOF). To keep the pulse length nearly constant, it is possible to use Dispersion Compensating Fibre (DCF) that shall be installed at the regenerators that provide amplification, renewal of timing and pulse duration. DCFs have negative dispersion parameter; CD accumulating between regenerators is then suppressed. Consequently, bit error rate could be improved and the fibre reach could be extended.

Investigation of optical thin films printed on the surface of facets of photonic crystal fibers

  • Autoři: Ing. Michal Lucki, Ph.D., Kraus, S., Zelený, R., Zehetner, J., Seyringer, D., Latal, J., Perecar, F.
  • Publikace: Micro-structured and Specialty Optical Fibres IV. Bellingham: SPIE, 2015. PROCEEDINGS OF SPIE VOLUME 9507. ISSN 0277-786X. ISBN 9781628416282.
  • Rok: 2015
  • DOI: 10.1117/12.2182203
  • Odkaz: https://doi.org/10.1117/12.2182203
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Several different structures of photonic crystal fibres and materials are considered to show influence of such thin-film on signal properties. This investigation is carried out in context of abilities of ablation of material from surfaces of photonic crystal fibres. Only certain shapes and geometrical arrangements can be considered. One of the goals is to specify, which of them are key for potential modification of spectral characteristics of photonic crystal fibres. The printed structures could potentially work like a thin-film ablation. Rigorous and versatile finite difference method has been employed to model propagation of light, its incidence onto a surface of the photonic crystal fibre, and subsequent propagation down the fibre. The simulations are carried on small pieces of photonic crystal fibres, with the length of tens of micrometres, due to well-known demands of the simulation technique on computational resources.

Laser ablation for membrane processing of AlGaN/GaN- and micro structured ferroelectric thin film MEMS and SiC pressure sensors for extreme conditions

  • Autoři: Zehetner, J., Vanko, G., Dzuba, J., Ryger, I., Lalinsky, T., Benkler, M., Ing. Michal Lucki, Ph.D.,
  • Publikace: Smart Sensors, Actuators, and MEMS VII; and Cyber Physical Systems. Bellingham: SPIE, 2015. ISSN 0277-786X. ISBN 978-1-62841-639-8.
  • Rok: 2015
  • DOI: 10.1117/12.2179041
  • Odkaz: https://doi.org/10.1117/12.2179041
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    AlGaN/GaN based high electron mobility transistors (HEMTs), Schottky diodes and/or resistors have been presented as sensing devices for mechanical or chemical sensors operating in extreme conditions. We demonstrated that a 4H-SiC 80μm thick diaphragms can be fabricated much faster with laser ablation than by electrochemical, photochemical or reactive ion etching (RIE). We were able to verify the feasibility of this process by fabrication of micromechanical membrane structures also in bulk 3C-SiC, borosilicate glass, sapphire and Al2O3 ceramic substrates by femtosecond laser (520nm) ablation. On a 350μm thick 4H-SiC substrate we produced an array of 275μm deep and 1000μm to 3000μm of diameter blind holes without damaging the 2μm AlN layer at the back side. In addition we investigated ferroelectric thin films as they can be deposited and micro-patterned by a direct UV-lithography method after the ablation process for a specific membrane design.

LASER GENERATED MICRO - AND NANOSTRUCTURES AND THE TRANSFER TO POLYMERS FOR EXPE RIMENTAL USE

  • Autoři: Zehetner, H., Schmidmayr, D., Piredda, G., Kasemann, S., Matyliskaya, V., Ing. Michal Lucki, Ph.D.,
  • Publikace: Proceedings of the 21 th International conference on APPLIED PHYSICS OF CONDENSED MATTER. Bratislava: Slovak University of Technology in Bratislava, 2015. pp. 282-285. ISBN 978-80-227-4373-0.
  • Rok: 2015
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Our experiments reveal fs-laser texturing can create μm-sized structures, LIPPS and HSFL with practically a single shot. Ps-laser ablation can generate ripples in certain materials but not as distinct as fs-ablation. Additional treatments of material interfaces offer the opportunity to obtain a wider bread thin shape and scale for nanometer structures on a given material. Post-treatment of laser textured-surfaces by sputtering, oxidation, wet etching or RIE will considerably increase application opportunities in photonics and optics. Sensor devices on laboratory scale implementing nano-structures can be generated cost efficient.

Laser polarization condition affecting ablation quality of thin membranes for SiC or ceramic based GaN/ferroelectric thin film MEMS and pressure sensors

  • Autoři: Zehetner, J., Domke, M., Piredda, G., Kraus, S., Ing. Michal Lucki, Ph.D., Vanko, G., Dzuba, J., Ryger, I., Lalinsky, T., Benkler, M.
  • Publikace: Proceedings of the 7th International Congress on Laser Advanced Materials Processing. Osaka: JAPAN LASER PROCESSING SOCIETY, 2015. pp. 1-6.
  • Rok: 2015
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    AlGaN/GaN-based high electron mobility transistors (HEMTs), Schottky diodes and/or resistors have been presented as sensing devices for mechanical or chemical sensors operating in extreme conditions. Creation of appropriate diaphragms and/or cantilevers out of SiC is necessary for further improvement of sensing properties of such MEMS sensors. For exam-ple, the sensitivity of the AlGaN/GaN based MEMS pressure sensor can be modified by membrane thickness. We demon-strated that 4H-SiC 80 µm thick diaphragms can be fabricated much faster with laser ablation than by electrochemical, photochemical or reactive ion etching (RIE). We were able to verify the feasibility of this process by fabrication of micromechanical membrane structures also in bulk 3C-SiC, borosilicate glass, sapphire and Al2O3 ceramic substrates by femtosecond laser (520nm) ablation. On a 350 µm-thick 4H-SiC substrate we produced an array of 275 µm deep and 1000 µm to 3000 µm in diameter blind holes without damaging the 2 µm AlN layer at the back side. In additional experiments, we investigated ferroelectric thin films as they can be deposited and micro-patterned by a direct UV-lithography method after the ablation process for a specific membrane design. The risk to harm or damage the function of thin films was eliminated by that fabrication procedure. We observe that some defects in the ablated membranes are also affected by the polarisation of the laser light. Ripple structures oriented perpendicularly to the laser polarisation promote creation of pin holes which would perforate a thin membrane. We developed an ablation technique strongly inhibiting for-mation of ripples and pin holes.

Obvodová, objektová a předmětová ochrana majetku - principy

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Vývoj systémů na zakázku nemůže bazírovat pouze na komerčně dostupných senzorech a kamerách. Taková práce vyžaduje pokročilou znalost procesů, schopnost tvoření modelů těchto procesů a měřených veličin, dlouhý výzkum a vývoj a optimalizační postupy. Přesto se v tomto článku pokusím systematizovat vybrané aspekty mechanických zabezpečovacích systémů pro ochranu majetku. Přesto zdůrazňuji, že neexistuje recept nebo univerzální návod, dle kterého lze zabezpečit každý objekt.

Optické mikrofony nebo elektronické odposlechy – jasná volba

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Optoelektronické perimetry ovládly trh distribuovaných zabezpečovacích systémů pro hlídání rozsáhlých ploch (letiště, parkoviště) a budov (hrady, domy podnikatelů, úřady, banky). Bezkontaktní měření amplitudy vibrací a indikace narušení hlídaného prostoru je primárním úkolem perimetru, přesto interferometrické systémy nabízí další zajímavou aplikací, která může rozšířit funkce zabezpečovacího systému (dobré zabezpečení je vždy víceúrovňové). Touto aplikací je takzvaný optický mikrofon. Myšlenka „optického mikrofonu“, kdy stačí mluvit na vlákno, zní bizarně, v praxi nejde o žádnou komerčně dostupnou „hračku“ pro nahrávání hudby, ale o sofistikovanou špionážní, odposlechovou techniku, která je schopná zaznamenávat spektra neelektrickou metodou, je tedy nedetekovatelná běžnou měřicí technikou.

Software design of segment optical transmitter for indoor free-space optical networks

  • Autoři: Latal, J., Vitasek, J., Koudelka, P., Siska, P., Liner, A., Hajek, L., Vanderka, A., Vasinek, V., Ing. Michal Lucki, Ph.D.,
  • Publikace: Broadband Access Communication Technologies IX. Bellingham: SPIE, 2015. ISSN 0277-786X. ISBN 9781628414776.
  • Rok: 2015
  • DOI: 10.1117/12.2087118
  • Odkaz: https://doi.org/10.1117/12.2087118
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The indoor free space optical networks have been experiencing dramatic progress in the last years, allowed by the newest IEEE norm 802.15.7, which enabled development of different types of transmitter receivers, modulation formats, etc. The team of authors is dealing with software design of segment optical transmitters for an indoor free space optical network based on the multi-mode optical 50/125 or 62.5/125 μm fiber. Simulated data are then evaluated from the point of view of optical intensity uniform distribution and space spot light size radiating from segment optical transmitter.

System improvements in dense wavelength division multiplexing networks by using advanced optical modulation formats

  • Autoři: Agalliu, R., Ing. Michal Lucki, Ph.D.,
  • Publikace: Proceedings on 17th International Conference on Transparent Optical Networks. Warsaw: National Institute of Telecommunications, 2015. pp. 1-4. ISSN 2162-7339. ISBN 978-1-4673-7880-2.
  • Rok: 2015
  • DOI: 10.1109/ICTON.2015.7193511
  • Odkaz: https://doi.org/10.1109/ICTON.2015.7193511
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    In this paper we focus on modulation formats for optical transmission networks. The most widely used intensity formats such as Non Return to Zero, Return to Zero, Carrier-Suppressed Return to Zero and duobinary are investigated in terms of bit error rate, Q-factor, optical reach and dense wavelength division multiplexing grid, in order to find out their physical limitations and system performance in a transmission system with given parameters. However, phase-based modulation formats like Differential Phase-Shift Keying and Differential Quadrature Phase-Shift Keying can perform better at the cost of increased transceiver's complexity. Some formats can benefit from polarization division multiplexing to enable higher spectral efficiency, optical reaches, optical to signal noise ratio and chromatic dispersion tolerances. Simulations are performed in OptSim software environment based on the Time Domain Split Step method which uses full band simulation and offers aliasing errors immunity, accurate differential group delays, parallel computing, etc.

The Impacts of Ageing Effects Due to Radiation Burden on Optical Fiber Couplers

  • Autoři: Perecar, F., Marcinka, 0., Bednarek, L., Ing. Michal Lucki, Ph.D., Liner, A., Hajek, L., Papes, M., Jaros, J., Vasinek, V.
  • Publikace: Photonic Fiber and Crystal Devices: Advances in Materials and Innovations in Device Applications IX. Bellingham: SPIE, 2015. ISSN 0277-786X. ISBN 9781628417524.
  • Rok: 2015
  • DOI: 10.1117/12.2187517
  • Odkaz: https://doi.org/10.1117/12.2187517
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The paper discuss about accelerated ageing of optical fiber elements in their burdened with gamma radiation. In addition to the destruction of coating materials, gamma radiation has its effect on the internal structure of the optical fiber. It is necessary to specify the changes in the optical coupler and find out why these changes occur. This article contains experimental measurement of the impact of gamma radiation Cobalt-60 on the optical couplers of various split performance ratio. The couplers were exposed to gradually increasing doses of Co-60. Measurements are focused on the overall distribution of the energy in the core and cladding various branches of SM optical fiber couplers.

Benefits and Limits of Modulation Formats for Optical Communications

  • Autoři: Agalliu, R., Ing. Michal Lucki, Ph.D.,
  • Publikace: Advances in Electrical and Electronic Engineering. 2014, 12(2), 160-167. ISSN 1336-1376.
  • Rok: 2014
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This paper is focused on benefits and limits of intensity and phase modulation formats used in optical communications. The simulation results are obtained using OptSim software environment, employing Time Domain Split Step method. Non-Return to Zero, Return to Zero, Chirped Return to Zero and Carrier-Suppressed Return to Zero formats are compared in terms of Bit Error Rate and spectral efficiency to find the limits for selected transmission network topologies. It is shown that phase modulation formats offer many advantages compared to intensity formats. Differential Phase-Shift Keying and mainly Differential Quadrature Phase-Shift Keying improve the Bit Error Rate and transmission reach, among others. A promising solution is the application of Polarization Division Multiplexing Quadrature Phase-Shift Keying, which primarily benefits in spectral efficiency, estimated reach, optical signal to noise ratio and chromatic dispersion tolerances.

Design of a Narrowband Photonic Filter Based on the Leaky Outer Defect Mode

  • Autoři: Zelený, R., Ing. Michal Lucki, Ph.D.,
  • Publikace: 16th Mechatronika 2014. Brno: Brno University of Technology, 2014. pp. 428-432. ISBN 978-80-214-4817-9.
  • Rok: 2014
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This paper presents a novel design of a narrow stopband photonic crystal fiber filter based on the phase matching between the inner fundamental mode and leaky outer defect mode. The significant leakage loss of the outer defect mode is obtained by the reduced diameters of the cladding airholes. Through the investigation of the proposed fiber, it has been found that doping the inner core by germanium dioxide is responsible for the strong confinement of the fundamental mode in the core; significant field transfer to the leaky outer core occurs only in the narrow wavelength spectra making the stopband. Tuning the fiber geometry, the desirable position of the stop-bands can be set as well as the power ratio between the stopand pass-bands. The ratio can be up to 180 dB at the wavelength of 1.55 μm using the 10 cm long fiber, while the minimum number of airholes and design parameters is ensured. The position of stop-band depends on fiber geometry. We predict that such high sensitivity can be used to make a fiber-based sensor. The fiber mode properties are obtained using the finite difference eigenmode solver.

Dispersion limits in the design of small-mode-area photonic crystal fibers

  • Autoři: Zelený, R., Ing. Michal Lucki, Ph.D.,
  • Publikace: Optical Engineering. 2014, 53(10), ISSN 0091-3286.
  • Rok: 2014
  • DOI: 10.1117/1.OE.53.10.105103
  • Odkaz: https://doi.org/10.1117/1.OE.53.10.105103
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Understanding the mechanism governing chromatic dispersion is necessary not only for the fiber design and dispersion tailoring, but also to predict the potential manufacturing tolerances. In spite of the fact that the fiber with specific parameters matches its relative dispersion slope to that of standard single mode fibers over the large range of operating wavelengths, the negative dispersion parameter is not higher than in commercially available dispersion compensating fibers. Therefore the fiber parameters are modified to find the balance between the operating bandwidth and the high negative dispersion parameter. The limit value for the dispersion parameter is found to be −1600 ps·nm−1·km−1 at 1550 nm, whereas the dispersion slope is achieved for the 120 nm wide band. We predict that the negative dispersion parameter cannot be higher in the small effective mode area photonic crystal fibers operating over the bandwidth larger than the one considered in our paper.

Dispersion limits of the small mode area photonic crystal fibers designed as a broadband compensator

  • Autoři: Zelený, R., Ing. Michal Lucki, Ph.D.,
  • Publikace: Micro-structured and Specialty Optical Fibres III. Bellingham: SPIE, 2014. Micro-structured and Specialty Optical Fibres III. ISBN 9781628410761.
  • Rok: 2014
  • DOI: 10.1117/12.2051934
  • Odkaz: https://doi.org/10.1117/12.2051934
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Nonlinear photonic crystal fibers with small effective mode area allow to control chromatic dispersion in the near-infrared region. In this paper the chromatic dispersion is controlled entirely by structural parameters and the influence of each structural parameter is examined and described in detail. Understanding of the influence not only permits fiber design and dispersion tailoring, but also predicts the potential manufacturing tolerances. As a consequence, the fiber structural parameters are modified to found the balance between the operating bandwidth and the high negative dispersion parameter. We predict that the negative dispersion parameter cannot be higher in the small effective mode area photonic crystal fibers operating over the bandwidth larger than the one considered in our paper.

Fiber Optic and Free Space Michelson Interferometer - Principle and Practice

  • DOI: 10.5772/57149
  • Odkaz: https://doi.org/10.5772/57149
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Michelson interferometer is used in metrology of small amplitude nonelectric physical quantities for its accuracy, noncontact and noninvasive procedure. It is broadly used in sensor applications. There are many papers assuming the use of an interferometer and focusing on measured results, but there are not many works offering practical knowledge on how to construct and run Michelson interferometer. In this chapter we discuss wide range of aspects, which greatly facilitate the launch of Michelson interferometer in in-situ conditions.

Laser ablation - fundamentals and application

  • Autoři: Ing. Michal Lucki, Ph.D., Kraus, S., Zelený, R.
  • Publikace: 26th Conference and Exhibition on Optical Communications 2014 Proceedings. Praha: Agentura Action M, 2014. pp. 39-43. ISBN 978-80-86742-39-7.
  • Rok: 2014
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The goal of this paper is to present fundamentals of laser ablation, which is the process of removing material from a solid using short (e.g. femtosecond) laser pulses. Laser ablation is potentially interesting for precise object forming in optical glasses that could open door to new fabrication technologies of optical thin films, among others. The process depends on flux received by each point of the surface, as according to the generally accepted Neuenschwander model of ablation. However, there are many secondary aspects that have been recently investigated, making this problem an actual and still unsolved topic. Some of them can be the cut V-groove width and depth, the penetration depth, the property of material, the shape of pulses and spot size, mode distribution incident to the groove cut by the laser and pulse duration.

Limits of advanced modulation formats for transition in fiber optic telecommunication systems to increase speeds from 10, 40, 100 Gb

  • Autoři: Ing. Michal Lucki, Ph.D., Agalliu, R., Zelený, R.
  • Publikace: Optical Modelling and Design III. Bellingham: SPIE, 2014. Proceedings of SPIE Volume 9131. ISBN 9781628410792.
  • Rok: 2014
  • DOI: 10.1117/12.2054279
  • Odkaz: https://doi.org/10.1117/12.2054279
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    In this paper we investigate limits of intensity and phase modulation formats used in optical communications. including the most actual solutions, such as Polarization Division Multiplexing Quadrature Phase-Shift Keying, are investigated in terms of spectral efficiency, Bit Error Rate to find the limits for selected topologies and spectral grids in Dense Wavelength Division Multiplexing. Differential Phase-Shift Keying and mainly Differential Quadrature Phase-Shift Keying offer improvements in Bit Error Rate and transmission reach, among others.

Optoelektronické senzory nové generace

  • Autoři: Ing. Michal Lucki, Ph.D., Davídková Antošová, M.
  • Publikace: Elektroinstalatér. 2014, 20(2/2014), 58-60. ISSN 1211-2291.
  • Rok: 2014
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Perimetry a hydrofony jsou jedny z nejrozšířenějších prvků bezpečnostních systémů. Aktuální otázkou u návrhu senzorů je nastavení pracovní oblasti, citlivosti a přesnosti, problém falešných poplachů, teplotní a mechanické stability systému, nebo vliv polarizace či koherenční délky, které budou v této rubrice vysvětleny.

Precise optical differential thermometer sensor based on interferometric measurement of thermal expansion coefficient

  • DOI: 10.1117/12.2054346
  • Odkaz: https://doi.org/10.1117/12.2054346
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Knowing a thermal expansion coefficient and measured exact thermal expansion, it is possible to design a very sensitive sensor measuring temperature differential. A Michelson interferometer is used to determine temperature changes. It measures linear expansion on a metal object, e.g. a copper rod, as a change in length in response to a change in temperature. Based on the obtained interferograms and knowing the value of thermal expansion coefficient, temperature differential can be calculated. The accuracy of the procedure can be determined by using the exact differential method based on the measurement errors for linear expansion, and initial length. The contribution of this paper is the employment of Michelson interferometer to design a very sensitive differential thermometer measuring with the accuracy of one thousandth degree Celsius. It results from the achieved precision of measuring the optical path length changes in the range of hundreds nanometers. The advantage of this sensor is its precision and noncontact procedure.

Structural Tolerances of Optical Characteristics in Various types of Photonic Lattices

  • Autoři: Kraus, S., Ing. Michal Lucki, Ph.D.,
  • Publikace: Advances in Electrical and Electronic Engineering. 2014, 12(3), 245-251. ISSN 1336-1376.
  • Rok: 2014
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    A systematic study of various photonic crystal lattices and their optical characteristics is carried out in this paper. Sensitivity of both dispersion and effective mode area characteristics to deviations of particular structural parameters of the lattices are the main studied topics. The presented results can be exploited during the design of fibers and new devices utilizing the studied lattices, when strict requirements on optical characteristics of the fabricated devices are imposed. Performance benefits for the implementation of particular lattices types in photonic designs are shown.

Vývoj optovláknového interferometrického bezpečnostního senzorů

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Interferometrické senzory mohou pracovat jako optické mikrofony, odposlechy nebo nášlapové senzory či senzory vibrace, proto s ohledem na aplikační oblasti se tato problematika jeví jako velice perspektivní. V tomto článku shrnujeme praktické aspekty, které umožňují systematický přístup k návrhu a zprovoznění optických senzorů v praxi.

Vývoj optovláknového interferometrického bezpečnostního senzorů

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Interferometrické senzory mohou pracovat jako optické mikrofony, odposlechy nebo nášlapové senzory či senzory vibrace, proto s ohledem na aplikační oblasti se tato problematika jeví jako velice perspektivní. V tomto článku shrnujeme praktické aspekty, které umožňují systematický přístup k návrhu a zprovoznění optických senzorů v praxi.

Vývoj optovláknového interferometrického bezpečnostního senzorů

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Interferometrické senzory mohou pracovat jako optické mikrofony, odposlechy nebo nášlapové senzory či senzory vibrace, proto s ohledem na aplikační oblasti se tato problematika jeví jako velice perspektivní. V tomto článku shrnujeme praktické aspekty, které umožňují systematický přístup k návrhu a zprovoznění optických senzorů v praxi.

Broadband dispersion decreasing photonic crystal fiber for compression of optical pulses

  • Autoři: Zelený, R., Ing. Michal Lucki, Ph.D.,
  • Publikace: Micro-structured and Specialty Optical Fibres II. Bellingham: SPIE, 2013. pp. 87750Y-1-87750Y-8. 1. ISSN 0277-786X. ISBN 978-0-8194-9577-8.
  • Rok: 2013
  • DOI: 10.1117/12.2019298
  • Odkaz: https://doi.org/10.1117/12.2019298
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    A novel photonic crystal fiber for compression of optical pulses is designed and studied in this paper. The fiber comprises a silica core surrounded by nine rings of air-holes, where air-hole diameter of the innermost ring is gradually reduced along the entire fiber length. In order to obtain the required wavelength dependence of the effective refractive index, finite difference frequency domain method is employed. The calculated chromatic dispersion is flat from 1250 to 1700 nm at the fiber output, and therefore the photonic crystal fiber can be used at a desired wavelength in this range. On the contrary to other studies, chromatic dispersion in this paper is decreasing along the fiber length with the effective mode area. Therefore, during the propagation of solitary waves, the fiber nonlinear parameter increases and consequently the compression ratio is increased. Compression of solitary waves is investigated at the wavelengths of 1250, 1310, 1400, 1550, and 1700 nm. The compression ratio up to 30 for the first-order solitary wave with the length of 1550 nm can be achieved primarily by dispersion varied from 137 to 6 psnm-1km-1 during the wave propagation.

Broadband submicron flattened dispersion compensating fiber with asymmetrical fluoride doped core

  • Autoři: Ing. Michal Lucki, Ph.D., Zelený, R.
  • Publikace: Micro-structured and Specialty Optical Fibres II. Bellingham: SPIE, 2013. pp. 87750M-1-87750M-8. 1. ISSN 0277-786X. ISBN 978-0-8194-9577-8.
  • Rok: 2013
  • DOI: 10.1117/12.2017554
  • Odkaz: https://doi.org/10.1117/12.2017554
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The goal of this paper is to investigate selected fluoride optical materials and to present a photonic crystal fiber designed for specific applications in dispersion compensation by using those materials. The idea how to restrict chromatic dispersion is to increase the index contrast by using calcium fluoride or barium fluoride in the first ring of holes, which lower the effective index. The use of fluorides allows achieving broadband dispersion suppression impossible to achieve in standard fibers with similar geometry. The presented result comprises a numerical model of a photonic crystal fiber in a submicron lattice, specific for its negative dispersion coefficient achieved for broad spectrum of telecommunication wavelengths, i.e. 1300 – 1700 nm. Holes doped with fluoride materials enhance negative dispersion coefficient to -438 ps.nm-1.km-1. The major advantage of the designed fibers is their material composition, low attenuation and broadband utilization.

Nearly zero dispersion-flattened photonic crystal fiber with fluorine-doped three-fold symmetry core

  • Autoři: Zelený, R., Ing. Michal Lucki, Ph.D.,
  • Publikace: Optical Engineering. 2013, 52(4), ISSN 0091-3286.
  • Rok: 2013
  • DOI: 10.1117/1.OE.52.4.045003
  • Odkaz: https://doi.org/10.1117/1.OE.52.4.045003
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    A novel design of a photonic crystal fiber is presented. A nearly zero dispersion regime of operation has been achieved by using a three-fold symmetry core, which is improved by the avoidance of high-index doping in a central region. The core consists of pure silica surrounded by three fluorine-doped regions and three airholes. It can be confirmed by the numerical simulations using the finite difference frequency domain method that flattened dispersion characteristics upon wavelength over the range of 1250 to 1700 nm can be achieved in an optical fiber. Further, the potential fiber geometry imperfections caused some concern. Finally, the presented fiber design is compared to selected fiber designs with a dispersion close to zero.

An Improved Non-linear Nearly-zero Dispersion Flattened Photonic Crystal Fiber with the Threefold Symmetry Core

  • Autoři: Zelený, R., Ing. Michal Lucki, Ph.D.,
  • Publikace: Microstructured and Specialty Optical Fibres. Bellingham: SPIE, 2012. Proceedings of SPIE. ISSN 0277-786X. ISBN 978-0-8194-9118-3.
  • Rok: 2012
  • DOI: 10.1117/12.920064
  • Odkaz: https://doi.org/10.1117/12.920064
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    A new type of dispersion flattened photonic fiber is presented. The fiber has an improved threefold symmetry core that consists of a silica core surrounded by three low-index regions and three air-holes. It can be observed from numerical simulation employing the full-vectorial finite difference frequency domain method that nearly-zero ultra-flattened dispersion can be obtained over the wavelength range of 1250-1700 nm. All fiber's parameters are found to be non immune to imperfections of geometry. An attention should though be paid to the potential fabrication process. The chromatic dispersion behavior with fabrication tolerances of 1 % and 2 % has been numerically demonstrated. Finally, fiber designs with five different hole-to-hole spacing (pitch) have been proposed. Each of the proposed fibers exhibits remarkable chromatic dispersion properties, such as nearly-zero ultra-flattened dispersion over wide wavelength range or zero dispersion at the wavelength of 1550 nm.

An interferometric Measurement of Thermal Expansion Coefficient of Materials

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    A Michelson-type visible spatial interferometric method is used to measure a thermal expansion coefficient of metals. A He-Ne laser beam is split to create an inreferometric pattern consisting of a reference signal and a measuring signal coming from a copper rod, terminated with a 100% mirror, which can potentially be replaced by any other solid state resistant to heating. Since temperature is responsible for the increased length of the copper rod, the position of a mirror is changed and consequently, the interferogram is modified. Based on this, thermal expansion coefficient can be predicted and the type of material can be specified. In addition, heating and cooling processes exhibit a different time variation, which allows distinguishing between them employing this accurate and non-contact optical method.

Calculation of observational errors for an interferometric measurement by using exact differential method

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    An optical interferometric method is used to measure a thermal expansion coefficient of a copper rod. Heating process is responsible for the increased length of the investigated rod, placed in a measuring arm of an interferometer. Based on obtained interferograms and the measurement of initial length and temperature changes, thermal expansion coefficient is calculated. Potential observation errors originated at the measurements of initial length and temperature are considered. Mathematical apparatus as well as sample calculations of observational errors and the estimation of overall accuracy of measured thermal expansion coefficient are obtained by using an exact differential method.

Dispersion Compensating Photonic Crystal Fiber with Enhanced Properties Achieved by Modified Core Geometry

  • Autoři: Kraus, S., Ing. Michal Lucki, Ph.D.,
  • Publikace: Advances in Electrical and Electronic Engineering. 2012, 10(2), 101-105. ISSN 1336-1376.
  • Rok: 2012
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    A novel dispersion compensating fiber based on photonic crystal fiber has been designed and studied in terms of optimal dispersion and operating bandwidth. The investigation of dispersion characteristics with respect to change in hole diameter and pitch has been provided. Further optimization of the designed fiber has been applied to the achieved fiber's properties in order to achieve a potentially easy-to-fabricate dispersion compensating fiber.

Novel Large Effective Mode Area Photonic Crystal Fiber with Zero Dispersion at 1550 nm

  • Autoři: Zelený, R., Ing. Michal Lucki, Ph.D.,
  • Publikace: Research in Telecommunication Technologies Conference proceedings and Workshop. Žilina: Žilinská univerzita, 2012. pp. 185-188. ISBN 978-80-554-0570-4.
  • Rok: 2012
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    A new approach to design an index-guiding photonic crystal fiber with large effective mode area is presented. The idea of enhancement the mode area is to introduce an air hole into the fiber's core. It results to the enlarged mode area of light, which extends into thirteen rings of air holes with sufficient small diameter. Further, light is strong confined by the six remaining rings of air-holes with relatively high air-fraction volume. Therefore presented fiber exhibits very low leakage loss. As observed from the numerical simulations, by tuning the diameter of air-holes, zero dispersion at a specific wavelength can be obtained. A zero dispersion wavelength can be achieved over the C and L bands, which can be used in telecommunication applications.

Photonic Crystal Fibers with Optimized Dispersion for Telecommunication Systems

  • Autoři: Ing. Michal Lucki, Ph.D.,
  • Publikace: Recent Progress in Optical Fiber Research. Rijeka: InTech, 2012. p. 177-192. ISBN 978-953-307-823-6.
  • Rok: 2012
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The use of Photonic Crystal Fibers (PCF) is understood within their unique chromatic dispersion characteristics and nonlinear behavior, which is suitable for dispersion compensation or transmission of information without pulse spreading, leading to an intersymbol interference. Pulse spreading being the result of chromatic dispersion in optical fibers is considered as one of the critical issues in the design of optical fibers. Since the dispersion can result in worse system performance, it is necessary to prevent its occurrence or to compensate it. A systematic study of dispersion properties in PCFs is presented. The investigation includes a description of fiber chromatic dispersion dependence on structural and material parameters. Potential zero or anomalous dispersion in doped PCFs is achieved. An overview of current innovations on the studied problem is presented. Moreover, the new PCF with nearly zero ultra-flattened chromatic dispersion is introduced. It is shown from the numerical results that the dispersion of -0.025 ps/nm/km is available from the wavelength of 1200 nm to 1700 nm.

Selected Aspects of Interferometric Measurements of Non-electric Low-amplitude Physical Quantities

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    A Michelson-type visible spatial interferometric method is used to measure very high speed vibrations of a bass-reflex loudspeaker, and further its resonant frequency. The goal of investigation is to create the model for measurement of non-electric, low-amplitude, high-speed alternating physical quantities. The contribution of this paper is this new application area.

Single-Material Submicron Microstructured Fibres for Broadband Applications in Exact Slope Compensation or Zero- Dispersion Propagation

  • Autoři: Ing. Michal Lucki, Ph.D., Jiruše, D., Kraus, S.
  • Publikace: 14th International Conference on Transparent Optical Networks (ICTON). Piscataway: IEEE, 2012. pp. Tu.P.28. ISSN 2161-2056. ISBN 978-1-4673-2227-0.
  • Rok: 2012
  • DOI: 10.1109/ICTON.2012.6253821
  • Odkaz: https://doi.org/10.1109/ICTON.2012.6253821
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The goal of this paper is to present novel broadband optical fibres suitable for exact dispersion slope compensation of standard fibres used in telecommunications. The results were obtained in a submicron lattice by optimizing the single-material PCF's geometry, avoiding the use of doping technique. Linear dispersion upon wavelength is achieved concurrently to optimal dispersion slope, which exactly matches the characteristics of ITU-T fibres. Last but not least, a fibre for broadband zero-dispersion transmission is presented. The major advantage of the designed fibres is their material composition, low attenuation and broadband utilization.

Stress-induced Birefringent Photonic Crystal Fiber

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The goal of this paper is to present a novel single-material photonic crystal fiber utilizing stress-induced birefringence for detection of unidirectional load applied onto the fiber. Particular contributions to the birefringence, which are the deformation of fiber's geometry and stress-induced variation in refractive index, are considered in the proposed fiber.

A Nearly-Zero Ultra-Flattened Dispersion Photonic Crystal Fiber with Low Confinement Loss for Broadband Transmission Systems

  • Autoři: Zelený, R., Botah, K., Ing. Michal Lucki, Ph.D.,
  • Publikace: 23rd Conference and Exhibition on Optical Communications 2011 - Scientific Section Proceedings. Praha: Agentura Action M, 2011. pp. 45-47. ISBN 978-80-86742-32-8.
  • Rok: 2011
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The presented paper describes a novel index guiding photonic crystal fiber, in which its core is surrounded by air holes with three different values of diameter. A nearly-zero ultra-flattened dispersion photonic crystal fiber with low confinement loss is presented. The simulation of the proposed design was carried out using the finite difference frequency domain method.

Broadband Dispersion Compensating Photonic Crystal Fiber

  • Autoři: Ing. Michal Lucki, Ph.D., Zelený, R.
  • Publikace: Proc. of SPIE Vol. 8306. Bellingham (stát Washington): SPIE, 2011. pp. 83060Z-1-83060Z-6. ISSN 0277-786X. ISBN 978-0-8194-8953-1.
  • Rok: 2011
  • DOI: 10.1117/12.910720
  • Odkaz: https://doi.org/10.1117/12.910720
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The main objective is to design photonic crystal fibers suitable for potential compensation of group velocity dispersion of optical signals. A flattened-dispersion compensating photonic crystal fiber for broadband utilization in high-speed transmission systems with wavelength division multiplexing is proposed. The structure shows flattened dispersion over the O, C, and L bands. Last but not least, a dual-core compensating microstructured fiber is optimized in order to achieve low dispersion and low loss at the C-band.

Dispersion Compensating Photonic Crystal Fiber with Defected Core

  • Autoři: Kraus, S., Botah, K., Ing. Michal Lucki, Ph.D.,
  • Publikace: 23rd Conference and Exhibition on Optical Communications 2011 - Scientific Section Proceedings. Praha: Agentura Action M, 2011. pp. 34-36. ISBN 978-80-86742-32-8.
  • Rok: 2011
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The goal of this paper is to present a dispersion compensating fiber design, based on the index-guiding photonic crystal fiber, which can be considered for potential fabrication. Dispersion characteristics of the proposed fiber are investigated with a focus on the potential chromatic dispersion compensation of conventional single-mode fibers.

Dispersion Effects of Fiber Bending Performed on Microstructured Fiber

  • Autoři: Ing. Michal Lucki, Ph.D.,
  • Publikace: Acta Electrotechnica et Informatica. 2011, 11(2), 37-43. ISSN 1335-8243.
  • Rok: 2011
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Coupling modes, as well as anomalous chromatic dispersion can be achieved by fiber bending. An operating wavelength can be tuned by reason of bending. Minimum values of dispersion and of a minimum-dispersion wavelength can be controlled by bending radius. This fact should be taken into account in the designs of fibers immune to bending.

Optimization of Microstructured Fiber for Dispersion Compensation Purposes

  • Autoři: Ing. Michal Lucki, Ph.D.,
  • Publikace: 2011 13th International Conference on Transparent Optical Networks (ICTON). Piscataway: IEEE, 2011. pp. Tu.P.12. ISSN 2161-2056. ISBN 978-1-4577-0880-0.
  • Rok: 2011
  • DOI: 10.1109/ICTON.2011.5971024
  • Odkaz: https://doi.org/10.1109/ICTON.2011.5971024
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    A new dispersion compensating microstructured optical fiber is presented. The dispersion slope of the designed fiber is opposite to the dispersion of standard PCF for potential broadband dispersion compensation. Since chromatic dispersion is optimized for wide bandwidth, the considered structure is suitable for repeaters in transmission systems with wavelength division multiplex. Another contribution of this work is a new flat-dispersion PCF operating at telecom wavelengths. Dispersion of -0.025 ps/nm/km from a wavelength of 1200 nm to 1700 nm is achieved.

Optimization of Transmission Losses for Potential Optical High-pass Filter Based on Photonic Crystal Fibers

  • Autoři: Ing. Michal Lucki, Ph.D.,
  • Publikace: 13th International Conference on Research in Telecommunication Technologies 2011. Brno: VUT v Brně, Fakulta elektrotechniky a komunikačních technologií, 2011. pp. 170-173. ISBN 978-80-214-4283-2.
  • Rok: 2011
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The goal of this paper is to present a new optical component, which could operate as a high-pass filter or an optical attenuator. The component is based on microstructured optical fiber. Design tools to determine the boundary operation wavelength of the filter is described.

Photonic Crystal Fiber with Flattened Dispersion

  • Autoři: Ing. Michal Lucki, Ph.D.,
  • Publikace: Proceedings of SPIE Vol. 8073 - Optical Sensors 2011; and Photonic Crystal Fibers V. Bellingham: SPIE, 2011. pp. 80732P-1-80732P-9. Proceedings of SPIE. ISSN 0277-786X. ISBN 978-0-8194-8663-9.
  • Rok: 2011
  • DOI: 10.1117/12.886807
  • Odkaz: https://doi.org/10.1117/12.886807
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    A new flat-dispersion fiber operating at telecom wavelengths is designed. Required dispersion properties are achieved by balancing material and waveguide dispersion. Flat dispersion could be used for dispersion compensation purposes in systems with wavelength division multiplex. The main attention is paid to the optimization of photonic crystal fibers selectively doped by liquids. It is shown from numerical results that flattened dispersion of -0.025 ps/nm/km is achieved over the wavelength interval from 1200 nm to 1700 nm.

Recent Advances in the Dispersion Control of Photonic Crystal Fibers

  • Autoři: Botah, K., Ing. Michal Lucki, Ph.D.,
  • Publikace: 13th International Conference on Research in Telecommunication Technologies 2011 - Vol. II Poster Section. Brno: VUT v Brně, Fakulta elektrotechniky a komunikačních technologií, 2011. pp. 31-34. ISBN 978-80-214-4283-2.
  • Rok: 2011
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Microstructured fibers present unique dispersive and nonlinear properties. A review of the latest developments in the structural design of photonic crystal fibers, in relation to obtaining fibers with a nearly-zero ultra-flattened dispersion, and fibers for the compensation of dispersion is provided, as well as their possible applications.

Transmission in Highly Nonlinear Photonic Crystal Fibers

  • Autoři: Botah, K., Ing. Michal Lucki, Ph.D.,
  • Publikace: Proceedings of the 2011 International Conference on Telecommunication Systems Management. Dallas, TX: American Telecommunications Systems Management Association Inc., 2011. pp. 153-159. ISBN 978-0-9820958-4-3.
  • Rok: 2011
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Photonic Crystal Fiber with specific dispersion properties for zero dispersion propagation, good for potential bit rate increase is designed. The optimization for different relations between core size and normalized hole diameter is presented together with the study of its effects in tuning the second zero dispersion wavelength to the telecommunication wavelength of 1550 nm.

Wielojęzyczny e-kurs "Telekomunikacja w automatyzacji przemysłowej" jako przykład wykorzystania technik multimedialnych w kształceniu na odległość

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    W pracy zaprezentowany został ośmiojęzyczny online kurs "Teleinformatyka w automatyzacji przemysłowej", który uzupełniono wielojęzycznym słownikiem wyrażeń technicznych oraz alternatywną wersją offline. Studenci (uczestnicy) kursu pochodzili z dziesięciu krajów Europy; studium prowadzone było w poszczególnych krajach pod opieką tutora (nauczyciela na odległość). Kurs "Teleinformatyka w automatyzacji przemysłowej" powstawał w latach 2008-2010 w ramach projektu Unii Europejskiej oraz programu Leonardo da Vinci o nazwie "E-Learning for Acquiring New Types of Skills - Continued". Kurs jest dostępny od dnia 15.03.2010 r.

Wielojęzyczny e-kurs "Telekomunikacja w automatyzacji przemysłowej" jako przykład wykorzystania technik multimedialnych w kształceniu na odległość

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    W pracy zaprezentowany został ośmiojęzyczny online kurs Teleinformatyka w automatyzacji przemysłowej, który uzupełniono wielojęzycznym słownikiem wyrażeń technicznych oraz alternatywną wersją offline. Studenci (uczestnicy) kursu pochodzili z dziesięciu krajów Europy; studium prowadzone było w poszczególnych krajach pod opieką tutora (nauczyciela na odległość). Kurs Teleinformatyka w automatyzacji przemysłowej powstawał w latach 2008-2010 w ramach projektu Unii Europejskiej oraz programu Leonardo da Vinci o nazwieE-Learning for Acquiring New Types of Skills - Continued. Kurs jest dostępny od dnia 15.03.2010 r.

Wykorzystanie środków obliczeniowych i multimedialnych w nauczaniu i badaniach w obszarze telekomunikacji

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    W pracy przedstawiono narzędzia wykorzystywane w Katedrze Telekomunikacji dla elektronicznego wspomagania nauczania. System Class Server do zarządzania kształceniem przeznaczony jest dla istniejących programów nauczania, natomiast platforma Moodle wykorzystywana jest dla obsługi nowych programów kształcenia. Obok tekstu strukturalnego, równań, przykładów czy rycin, dostępne szablony umożliwiają umieszczanie interaktywnych elementów multimedialnych w postaci animacji, ścieżki dźwiękowej, wideo oraz testów. Za jeden z najbardziej zaawansowanych elementów uważać można integrację obliczeń teoretycznych, prowadzonych w środowisku Matlab Web Server, z drugiej strony jednym z najbardziej kompleksowych rozwiązań jest powiązanie wspomnianych narzędzi z zadaniami laboratoryjnymi typu online, do których możliwy jest zdalny dostęp wraz z możliwością konfiguracji na odległość, bez konieczności fizycznej obecności w laboratorium.

Wykorzystanie środków obliczeniowych i multimedialnych w nauczaniu i badaniach w obszarze telekomunikacji

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    W pracy przedstawiono narzędzia wykorzystywane w Katedrze Telekomunikacji dla elektronicznego wspomagania nauczania. System Class Server do zarządzania kształceniem przeznaczony jest dla istniejących programów nauczania, natomiast platforma Moodle wykorzystywana jest dla obsługi nowych programów kształcenia. Obok tekstu strukturalnego, równań, przykładów czy rycin, dostępne szablony umożliwiają umieszczanie interaktywnych elementów multimedialnych w postaci animacji, ścieżki dźwiękowej, wideo oraz testów. Za jeden z najbardziej zaawansowanych elementów uważać można integrację obliczeń teoretycznych, prowadzonych w środowisku Matlab Web Server, z drugiej strony jednym z najbardziej kompleksowych rozwiązań jest powiązanie wspomnianych narzędzi z zadaniami laboratoryjnymi typu online, do których możliwy jest zdalny dostęp wraz z możliwością konfiguracji na odległość, bez konieczności fizycznej obecności w laboratorium.

Engineered Chromatic Dispersion in Photonic Crystal Fibers Selectively Doped with Water

  • Autoři: Ing. Michal Lucki, Ph.D.,
  • Publikace: ICTON 2010 Conference Proceedings. Piscataway: IEEE, 2010. pp. Mo.P.6. ISBN 978-1-4244-7797-5.
  • Rok: 2010
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The presented work deals with the topic of engineered zero chromatic dispersion and negative chromatic dispersion. The study of mutual relations of selected physical and optical quantities, referring to the studied structures is provided with the goal to achieve a well-defined procedure to design zero-dispersion microstructured optical fibers, immune to specific adjustments of fiber geometry, which commonly significantly contribute to resultant dispersion. The main attention is paid to photonic crystal fibers that exhibit unique properties, being the result of selective doping of rings of holes in considered structures by using water.

Inovace předmětu Optické komunikační systémy anglického studijního programu fakulty elektrotechnické ČVUT v Praze

  • Autoři: Ing. Michal Lucki, Ph.D.,
  • Publikace: wRTT 2010 Proceedings. Ostrava: VŠB - TUO, FEI, Katedra elektroniky a telekomunikační techniky, 2010. pp. 41-43. ISBN 978-80-248-2262-4.
  • Rok: 2010
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Cílem článku je prezentovat výstupy řešení problému inovace předmětu Optické komunikační systémy, jehož podstatou je modernizace cvičení předmětu tak, aby se studenti mohli efektivně zabývat nejnovějšími metody měření výkonnosti optických tras, s účelem pochopení problematiky optických síti jako celku.

Modeling of the Multi-Carrier Modulation Benefits for Data Transmission

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This paper is focused on finding a more suitable simulation principles used when calculating the benefits of multi-carrier modulation used for user data transmission. Consecutive chapters describe a simplified method of modeling the user data transmission performance with regard to the real parameters of the transmission environment. Concrete results for typical situations are calculated and discussed.

Photonic Crystal Fiber with Flattened Dispersion

  • Autoři: Ing. Michal Lucki, Ph.D.,
  • Publikace: Proceedings of the 2010 Networking and Electronic Commerce Research Conference. Dallas, TX: American Telecommunications Systems Management Association Inc., 2010. pp. 179-187. ISBN 978-0-9820958-3-6.
  • Rok: 2010
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Microstructured fiber can have two zero dispersion points, which can be tuned by adjusting the fiber geometry. Nearly flat zero dispersion over telecom spectrum can be produced. It could be used for dispersion compensation purposes in systems with wavelength division multiplex. The presented systematic study includes the description of mutual relations between fiber chromatic dispersion and the structural or material parameters.

Porovnání metod kompenzace chromatické disperze u klasického optického jednovidového vlákna

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Článek se zabývá porovnáním metod kompenzace chromatické disperze u klasického jednovidového optického vlákna. Popisuje dvě metody kompenzace: disperzi kompenzujícím vláknem a čerpovanou Braggovou mřížkou. Uvažuje i metody předkompenzace u zkoumané optické trasy o délce 100 km.

Selected Aspects of Recent Research in the Area of Photonic Crystal Fibers

  • Autoři: Kraus, S., Ing. Michal Lucki, Ph.D.,
  • Publikace: RTT 2010 Proceedings. Ostrava: VŠB - TUO, FEI, Katedra elektroniky a telekomunikační techniky, 2010. pp. 119-121. ISBN 978-80-248-2261-7.
  • Rok: 2010
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This paper deals with recent development in photonic crystal fibers with main attention focused to selected results of fiber-design enhancements leading to possible optimization of transmission systems.

Vybrané aspekty rušení v plně optických přenosových sítích

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Článek se zabývá problematikou plně optických přenosových sítí, využívajících vlnového multiplexu (Wavelength Division Multiplex - WDM). Provádí rozbor vlivů působících na kvalitu přenosu datové informace, porovnává dvě odlišné metody monitorování OSNR podél trasy.

Negative Chromatic Dispersion in Selected Types of Photonic Crystal Fibres Obtained by Bending

  • Autoři: Ing. Michal Lucki, Ph.D.,
  • Publikace: 11th International Conference on Transparent Optical Networks. Warsaw: National Institute of Telecommunications, 2009. pp. Tu.B1.6. ISBN 978-1-4244-4826-5.
  • Rok: 2009
  • DOI: 10.1109/ICTON.2009.5185081
  • Odkaz: https://doi.org/10.1109/ICTON.2009.5185081
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    It is theoretically possible to achieve huge negative chromatic dispersion by fibre bending (-185000 ps/nm/km). On one hand, fibre bending may result in negative chromatic dispersion or coupling modes, which can open possibilities for new applications, such as design of Photonic Crystal Fibres suitable for compensation of Group Velocity Dispersion or for tuning operating wavelengths of dispersion compensating PCFs. Last but not least, it can be a potential tool to design optical filters, optical switches, or directional couplers. On the other hand, fibre bending is responsible for huge bending losses. Minimum dispersion and minimum-dispersion wavelength can be determined by the value of bending radius together with the diameter of a core, normalized hole diameter and the hole pattern. Chromatic dispersion diagrams for bending at different values of bending radius and for different air-filling fraction are demonstrated.

Optical and Transmission Properties of Highly Nonlinear Photonic Crystal Fibers

  • Autoři: Ing. Michal Lucki, Ph.D., Elhamdany, M., de Vusio, F.
  • Publikace: 11th International Conference RTT 2009. Praha: České vysoké učení technické v Praze, 2009. pp. 0103_0006. ISBN 978-80-01-04410-0.
  • Rok: 2009
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This paper deals with optical properties in a Photonic Crystal Fiber PCF with a small doped core to obtain a highly nonlinear photonic crystal fiber. It is a modeling work, which discusses negative chromatic dispersion obtained by high index contrast in fibers with significant air fraction volume. An overview of highly nonlinear PCF is presented. The behavior of chromatic dispersion when changing structural parameters in a Highly Nonlinear PCF doped in the core is studied, as well as the tuning of zero dispersion wavelengths to longer wavelengths when enlarging the core diameter. Normalized hole diameter is also discussed by its influence in loss control. Normalized hole diameter affects also zero dispersion wavelength tuning, the effective area and as consequence in the high nonlinear coefficient that can be obtained for large values of normalized hole diameter.

Selected Aspects of Negative Chromatic Dispersion Resulting from Fiber Bending

  • Autoři: Ing. Michal Lucki, Ph.D.,
  • Publikace: Proceedings of the 2009 Networking and Electronic Commerce Research Conference (NAEC 2009). Dallas, TX: American Telecommunications Systems Management Association Inc., 2009. pp. 236-244. ISBN 978-0-9820958-2-9.
  • Rok: 2009
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The paper deals with the problem of negative chromatic dispersion (CD) obtained by fiber bending (-185000 ps/nm/km). Fiber bending is responsible for coupling modes, which can be used to design Photonic Crystal Fibers (PCF) suitable for dispersion compensation purposes or for tuning of operating wavelengths of Dispersion Compensating Fibers (DCF). Last but not least, it can be a potential tool for the design of optical filters, optical switches, or directional couplers. Minimum values of negative chromatic dispersion and of a minimum-dispersion wavelength can be controlled by the suitable alignment of bending radius. CD diagrams for bending at different radii and for different normalized hole diameter are presented.

Transmission Properties of Highly Nonlinear Photonic Crystal Fiber with Huge Air-Fraction Volume and Doped Core

  • Autoři: Ing. Michal Lucki, Ph.D.,
  • Publikace: 11th International Conference on Transparent Optical Networks. Warsaw: National Institute of Telecommunications, 2009. pp. Tu.B1.5. ISBN 978-1-4244-4826-5.
  • Rok: 2009
  • DOI: 10.1109/ICTON.2009.5185080
  • Odkaz: https://doi.org/10.1109/ICTON.2009.5185080
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Doped Photonic Crystal Fiber (PCF) confining the fundamental mode in a small high-index core can exhibits parabolic evolution of chromatic dispersion with two zero-dispersion points and flat negative chromatic dispersion over O-Band, S-Band, C-Band and L-Band. A generally accepted view is that the zero-dispersion point can be governed by selecting the appropriate diameter of a core. It allows for tuning the zero-dispersion wavelength over dozens of nanometers in the visible and near-infrared spectrum. By increasing the diameter of a core, first zero-dispersion wavelength is tuned into longer wavelengths. A complex study of factors influencing the selection of a zero-dispersion point and their mutual dependence has been provided. Another goal is potential extension of a flat-dispersion interval, optimization of the studied structure with the goal to obtain negative dispersion at wavelengths, which are commonly used in telecommunication for potential dispersion compensation.

A Short Overview of the Most Actual Problems in the Area of Fiber Bending and Chromatic Dispersion in Photonic Crystal Fibers

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This paper is oriented to present a short overview of chosen aspects in the area of Photonic Crystal Fibers, primarily nonlinear dispersion properties induced by fiber bending. This topic refers to applications of to microstructure optical components of high-speed transmission systems, such as dispersion compensator based on negative chromatic dispersion resulting from bending the fiber at certain radius.

Design of Photonic Crystal Fibers with Low Bending Losses

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This paper deals with Photonic Crystal Fibers (PCF) that is not sensitive to bending. On one hand, fiber bending may result in potential negative chromatic dispersion or coupling light from the fundamental mode into the cladding modes, which opens many possibilities to design microstructured optical components for all-optical PCF-based system (e.g. group velocity dispersion compensator) On the other hand, fiber bending is responsible for huge bending losses. The goal of this paper is to reduce bending losses in an operating range of the designed fiber. Reduction of bending losses could be considered in the fiber that would be single-mode for wide range of bending angles or bending radii, but the light is not being coupled into the cladding and the fiber is not sensitive to bending in an office environment.

Negative Chromatic Dispersion Generated by Introducing Curvature into Photonic Crystal Fiber

Negative Chromatic Dispersion in Selected Types of Photonic Crystal Fibers

  • Autoři: Ing. Michal Lucki, Ph.D.,
  • Publikace: RTT 2008. Bratislava: STU v Bratislave, 2008. ISBN 978-80-227-2939-0.
  • Rok: 2008
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    The investigation of Photonic Crystal Fibers (PCF) is focused on the application of nonlinear phenomena of quantum structures, such as the design of a microstructured directional coupler or of the compensator of Group Velocity Dispersion by using negative chromatic dispersion. The presented mechanism of fiber bending provides negative chromatic dispersion even ten times greater than classical dispersion compensating fibers not only due to the optimal selection of bending radii, but also because PCFs offer the flexible selection of the value of normalized hole diameter, as well as their configuration. In addition to the whole range of potential applications, there is an essential problem how to reduce bending losses. A detailed description of mode and dispersion properties of PCFs is developed with the use of a full-vector FDFD method.

Chosen Aspects of Negative Dispersion Generation in Index Guiding Photonic Crystal Fibers

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This paper deals with the new method of generation of negative waveguide dispersion for dispersion compensation purposes. It is possible to generate negative dispersion by bending waveguide. Only for certain values of bent radius for which cladding mode can appear it is possible to confine the mode and cause optical nonlinearities. Deformation of fundamental modes is possible in the multicore structure.

Negative Dispersion Generated by Introducing the Curvature into the Microstructured Fiber

  • Autoři: Ing. Michal Lucki, Ph.D.,
  • Publikace: Poster 2007. Praha: České vysoké učení technické v Praze, Fakulta elektrotechnická, 2007. pp. C_001.
  • Rok: 2007
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    This is a modeling work, which purports to show that negative dispersion may be generated in a PCF by introducing curvature into the fiber. Results from the study of a problem could be employed to a new dispersion compensating technique.

Photonic Band Gap in Hollow Core PCF Controlled by Fiber's Geometry

  • Autoři: Ing. Michal Lucki, Ph.D.,
  • Publikace: Poster 2007. Praha: České vysoké učení technické v Praze, Fakulta elektrotechnická, 2007. pp. C_005.
  • Rok: 2007
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Calculation of photonic band structure of a two-component Hollow Core Photonic Crystal Fiber arranged in a hexagonal lattice of circular holes, controlled by the index contrast, as well as by the diameter and configuration of low-index inclusions is presented. The occurrence and a relative size of a photonic band gap for investigated structure is calculated and discussed.

Přehled nejaktuálnějších vědeckých problémů v oblasti disperze u mikrostrukturních vláken

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Přehled nejaktuálnějších vědeckých problémů v oblasti disperze u mikrostrukturních vláken v kontextu současného výzkumu na ČVUT FEL.

The Sensitivity of Negative Dispersion Induced by Introducing the Curvature into the Index Guiding Photonic Crystal Fiber for Deviation of Geometrical Parameters

Analysis of Photonic Crystal Fibers Transmission Properties

  • Autoři: Ing. Michal Lucki, Ph.D.,
  • Publikace: Proceedings of Workshop 2006. Praha: České vysoké učení technické v Praze, 2006. pp. 32-33. ISBN 80-01-03439-9.
  • Rok: 2006

Comparison of Dispersion and Loss Parameter of Index Guiding Photonic Crystal Fibers with Hexagonal and Square Lattice

Flexible Control of Dispersion in Index Guiding Photonic Crystal Fibers Governed by Geometrical Parameters

Influence of Number of Rings on the Transmission Parameters of Index Guiding Photonic Crystal Fibers

  • Autoři: Ing. Michal Lucki, Ph.D.,
  • Publikace: POSTER 2006. Praha: České vysoké učení technické v Praze, 2006. pp. C01.
  • Rok: 2006
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Investigation of the influence of number of rings in the structure of Photonic Crystal Fiber on basic transmission parameters such as loss, group velocity dispersion, effective index, group index, group delay, group velocity, and constant of propagation.

Investigation of Optical Nonlinearities of Highly Nonlinear Photonic Crystal Fibers

Negative Dispersion in Index Guiding Photonic Crystal Fibers

Band Gap Structure as the Photonic Crystal Fiber Guidance Mechanism

New Type of a Guidance Mechanism in Photonic Crystal Fibers

  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Setting the band condition in a microstructure is described. The Mode Profile dependent on the band condition is presented. Cross-section patterns presenting the propagation of electromagnetic field are shown. The comparison of a guidance mechanism in various types of PCF's (Index Guiding Photonic Crystal Fibers, Hollow Core Photonic Crystal Fibers, Polarization Maintaining Fibers) is discussed.

New Type of a Guidance Mechanism in Photonic Crystal Fibers

Optimalization of Loss Parameter in Index Guiding Photonic Crystal Fibers in a Stage of Fiber's Design

  • Autoři: Ing. Michal Lucki, Ph.D.,
  • Publikace: Proceedings of the 5th International Conference for Students and Young Scientists Telecommunication in XXI Century. Kielce: Wydawnictvo Politechniki Swietokrzyskiej, 2005. pp. 29-36. ISBN 83-88906-36-4.
  • Rok: 2005
  • Pracoviště: Katedra telekomunikační techniky
  • Anotace:
    Possibilities of minimalisation of transmission losses in Index Guiding Photonic Crystal Fibers in a stage of design provided by a choice of a certain set of structural parameters

Za stránku zodpovídá: Ing. Mgr. Radovan Suk