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Effective Optical Function in Fibre Photonics Networks
Havliš, Ondřej ; Vlček, Čestmír (referee) ; Dostál, Otto (referee) ; Slavíček, Karel (advisor)
This dissertation focuses on efficient optical functions in fiber photonic networks, testbeds and multiband polygon. These functions include optical amplification, switching, routing and filtering of the optical spectrum. The theoretical part of the thesis deals with optical amplification, where different types of optical amplifiers are described. These employ various principles for their function, such as the use of Raman scattering, rare earth doped fibers – primarily Erbium, and lastly semiconductor structures. The practical part of the work is focused on the use and verification of efficient optical functions and their services, i.e. transmission of classical telecommunication data and transmission of ultra-stable quantities (transmission of accurate time and ultra-stable frequency) in fiber photonic network, testbeds and multiband polygon.
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Optical link intended for indoor network
Hrbáčková, Petra ; Vlček, Čestmír (referee) ; Wilfert, Otakar (advisor)
This thesis deals with the structure of the optical wireless link intended for indoor applications. Optical transmitters and optical receivers as the basic elements of optical links and their characteristics and parameters are described. The characteristics of lenses used in the transmitter and receiver are presented. The special chapter is devoted to the directional reflectance properties of surfaces. The last part of the thesis is focused on a specific proposal of the wireless optical links and its power level diagram.
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Utilization of light polarization when filtering the optical signal
Alexa, Jan ; Vlček, Čestmír (referee) ; Wilfert, Otakar (advisor)
This master thesis deals with the possibility of separation of useful signal from noise using polarization of laser radiation. This thesis is structured into 5 thematic units. The first unit is focused on laser radiation and its properties. The second part contains a deeper focus on the polarization of radiation, its description and the possibilities of measuring the polarization states. The third part of the thesis is devoted to the design of the measuring chains and identification of used elements. Chapter four contains measurement of status of the polarization and its results. The last chapter analyzes particular measuring chains outputs according to their spectral characteristics.
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Methods for testing of analog circuits
Kincl, Zdeněk ; Vlček, Čestmír (referee) ; Husák, Miroslav (referee) ; Kolka, Zdeněk (advisor)
Práce se zabývá metodami pro testování lineárních analogových obvodů v kmitočtové oblasti. Cílem je navrhnout efektivní metody pro automatické generování testovacího plánu. Snížením počtu měření a výpočetní náročnosti lze výrazně snížit náklady za testování. Práce se zabývá multifrekveční parametrickou poruchovou analýzou, která byla plně implementována do programu Matlab. Vhodnou volbou testovacích kmitočtů lze potlačit chyby měření a chyby způsobené výrobními tolerancemi obvodových prvků. Navržené metody pro optimální volbu kmitočtů byly statisticky ověřeny metodou MonteCarlo. Pro zvýšení přesnosti a snížení výpočetní náročnosti poruchové analýzy byly vyvinuty postupy založené na metodě nejmenších čtverců a přibližné symbolické analýze.
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FSO transceiver for link quality estimation
Novák, Marek ; Vlček, Čestmír (referee) ; Wilfert, Otakar (advisor)
Tato diplomová práce pojednává o zmírnění bitové chybovosti bezkabelového optického spoje s užitím principu reciprocity aplikovaného na komunikační kanál, spolu s možností kódování přenášených dat. V této práci je implementováno LDPC a Reed-Solomonovo kódování pro jejich vyhovující vlastnosti. Zbytková rámcová chybovost je vypočtena a k dispozici jako výstup systému, který je implementovaný v hradlovém poli (FPGA).
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Vector phase-sensitive measurement amplifier
Rejnuš, Milan ; Vlček, Čestmír (referee) ; Drexler, Petr (advisor)
The master’s thesis describes known methods of signal measurement using principle of synchronous detection. Various methods are presented, their principles are examined and the problems when using them are analyzed. Further, procedures for reduction of adverse effects are described also. Second part of this thesis is focused on the instrument design. The instrument is intended for detection and processing of the output signals in a given optometric system. The proposed device is designed to operate on the principle of synchronous detection method using a vector signal evaluation. Advantages and disadvantages are discussed below.
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Fiber Optics Distributed Systems
Čučka, Milan ; Róka,, Rastislav (referee) ; Vlček, Čestmír (referee) ; Smékal, Zdeněk (advisor)
The dissertation is focused on the research of optical fiber sensors, which are based mainly on interferometric methods. The principle of operation of individual types of sensors is analyzed in the framework of simulation models, using several simulation tools. Furthermore, the possibilities of the coexistence of the sensor system within the planned or existing transmission networks are described. The possibility of accurate vibration measurement, localization of the vibration source and possibly temperature measurement is discussed. The measurements are mainly based on interferometric methods.
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Power-Over-Fiber power supply
Kos, David ; Vlček, Čestmír (referee) ; Drexler, Petr (advisor)
This thesis deals with the possibilities of energy transmission by optical fiber for the purpose of powering of electronic systems. It comprises issues of electrical energy conversion to optical energy, coupling the power into the optical fiber, coupling between fiber and opto-electric transducer, conversion of optical energy to electrical energy, and transformation on required voltage levels. The principles of such Power-Over-Fiber are discussed in the first part of the work. Various technologies for the implementation of key system parts and their effectivity are discussed. In the next part, several Power-Over-Fiber commercial devices are compared. Subsequently, systems for Power-Over-Fiber experimental implementations are proposed. They are based on the utilization of semiconductor laser, multimode fiber, photovoltaic cell and related electronic circuits. The final part of the thesis deals with the construction of experimental systems and measurement of parameters of transmitted power and efficiency.
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Measurement and Monitoring Performance Parameters of Next Generation Networks
Grenar, David ; Vlček, Čestmír (referee) ; Róka,, Rastislav (referee) ; Smékal, Zdeněk (advisor)
The thesis is concentrated on the topic of next generation access networks. In the thesis, first of all, is conducted the analysis of the current state of knowledge with special focus on current technical and legislative developments and trends in access networks. The thesis describes the current structure of access networks and analyzes the current state of the issue of access technology. Measurement and testing methods for its verification depending on the type of network or operation of IP services are also described. Subsequently, the dissertation presents mathematical methods, that can be used in order to assess the access network model. In addition, recommendations and methods for monitoring and modelling access network data are evaluated. In particular, the subject of interest in this thesis is the issue of traffic intensity. The thesis presents a proposal for the construction of a mathematical modelling for the traffic profile and its application.
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