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Nonlinear phenomena in optical fibers
Burian, Radek ; Horváth, Tomáš (referee) ; Münster, Petr (advisor)
The subject of this thesis is to describe nonlinear phenomena in the optic fiber. The theoretical part describes a principle of transmission in optical fibers. Optics modules, fibers and their parameters are described marginally. Except nonlinear phenomena, there is also described linear phenomena such as attenuation, dispersion, scattering. In terms of nonlinear phenomena there is described second order phenomena such as Second harmonic generation (SHG), Sum and difference harmonic generation (SFG and DFG) and third order phenomena, such as Kerr effect, Third harmonic generation (THG), Four-wave mixing (FWM) and Cross phase modulation (XPM). There are also described nonlinear scattering, such as Raman´s and Brillouin´s scattering. The Four-wave mixing is simulated in the first half of the practical part. Four-wave mixing occurs in DWMD systems, where can invoke cross-talks between channels. In the second half of the practical part is measured this nonlinear phenomenon. The aim of the measurement is to understand the behaviour of the FWM and find the way how to eliminate its power. The Four-wave mixing measurement is based on the simulation. Second measurement is designed for Brillouin scattering. The conclusion from simulated and laboratory part from both measurements are compared with theoretical knowledge.
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Linear and nonlinear phenomena in optical access networks
Valášek, Martin ; Münster, Petr (referee) ; Šifta, Radim (advisor)
The aim of this thesis is an explanation of the problem linear and nonlinear phenomena in optical access networks. In the first chapter refers to a description of the optical fiber, description of the optical environment and the main part is theoretical and mathematical description of phenomena that operate in optical fibers. It is therefore a specific attenuation, dispersion, phenomena of second and third-order, nonlinear light scattering and solitons. Then there is the dismantling brief overview of the distribution of access networks and their description. The second part deals with specific simulation of these phenomena in the simulation program OptSim 5.2. All connections will be implemented in the block diagram Sample-Mode, in which using appropriate units and setting the right parameters, we will try to confirm the theoretical assumptions of the first part.
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Quantum key distribution
Klíčník, Ondřej ; Burda, Karel (referee) ; Münster, Petr (advisor)
This thesis is indirectly related to the bachelor thesis Quantum key distribution over optical fiber infrastructure. Unlike the previous paper, the focus will be mainly on the practical application of the QKD (Quantum key distribution) system Clavis3. For this reason, physical phenomena related to practically used QKD protocols are briefly explained in the theoretical part. These are mostly based on phase coding. In particular, special attention is paid to the Coherent one-way protocol (COW) implemented in Clavis3 devices. This protocol is also compared with practical implementations of the BB84 protocol. Furthermore, the principles of other advanced QKD techniques are outlined and the phenomena in the optical fiber that may affect the quantum channel are discussed. A separate chapter is also devoted to standardization and topologies of QKD networks. Last but not least, the thesis addresses the topic of attacks against practical implementations of QKD protocols. In the practical part, measurements aimed at practical deployment of Clavis3 devices in a common communication network are performed. These include the possibility of combining a quantum channel into a single fiber together with classical channels using Wavelength-division multiplexing (WDM) and the analysis of the effect of Raman noise on the maximum communication distance. At the same time, the robustness of the system against polarization changes and fiber manipulation is verified. Finally, the performance of the system using three-state and four-state versions of the COW protocol is compared and the eavesdropping simulation module is tested.
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Resilient fiber optic infrastructure
Spurný, Vladimír ; Kubánková, Anna (referee) ; Münster, Petr (advisor)
Optical networks are often mistaken for being secure, but there are ways to eavesdrop on the signal in an optical fiber without the user noticing. Cryptography is used to protect data, but quantum computing may threaten current encryption methods in the future. Misuse of active and passive elements affect the security of the optical infrastructure. The monitoring ports of active devices and the physical properties of optical fibre s pose risks for data leakage and eavesdropping. This work focuses on information transmission in optical fibers, data leakage risk analysis, and testbed design for measuring data signal interference. And then verifies the functionality of the workstation on a high-speed coherent transmission system.
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Nonlinear phenomena in optical fibers
Burian, Radek ; Horváth, Tomáš (referee) ; Münster, Petr (advisor)
The subject of this thesis is to describe nonlinear phenomena in the optic fiber. The theoretical part describes a principle of transmission in optical fibers. Optics modules, fibers and their parameters are described marginally. Except nonlinear phenomena, there is also described linear phenomena such as attenuation, dispersion, scattering. In terms of nonlinear phenomena there is described second order phenomena such as Second harmonic generation (SHG), Sum and difference harmonic generation (SFG and DFG) and third order phenomena, such as Kerr effect, Third harmonic generation (THG), Four-wave mixing (FWM) and Cross phase modulation (XPM). There are also described nonlinear scattering, such as Raman´s and Brillouin´s scattering. The Four-wave mixing is simulated in the first half of the practical part. Four-wave mixing occurs in DWMD systems, where can invoke cross-talks between channels. In the second half of the practical part is measured this nonlinear phenomenon. The aim of the measurement is to understand the behaviour of the FWM and find the way how to eliminate its power. The Four-wave mixing measurement is based on the simulation. Second measurement is designed for Brillouin scattering. The conclusion from simulated and laboratory part from both measurements are compared with theoretical knowledge.
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Nonlinear phenomena in electrokinetic chromatography
Dovhunová, Magda ; Dubský, Pavel (advisor) ; Koval, Dušan (referee) ; Ševčík, Juraj (referee)
Capillary electrophoresis often uses complexing agents since the interaction between the analyte and the complexing agent can result in achieving or improving the separation. Examples of such methods can be electrokinetic chromatography or affinity capillary electrophoresis (ACE). ACE is used to determine the complexing parameters. In case of chiral separation, this issue gets complicated, since the parameters of the two analytes (enantiomers) are not completely independent to one another. Therefore, a procedure has been proposed in this thesis, that should always be used to evaluate the complexing parameters of two enantiomers. Statistical evaluation of these parameters was assessed as well. This work also proposes a method that allows to determine the relative migration order of two enantiomers in two different complexing separation systems. The mathematical description of electrophoresis is based on continuity equations, that are inherently nonlinear. However, these equations can be linearized to obtain an approximate analytical solution. There was recently presented a generalized model, that enables inclusion of complete complexing equilibria in the theoretical description of electromigration. Thus, various phenomena, including nonlinear ones, associated with complexation can be predicted. This...
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Linear and nonlinear phenomena in optical access networks
Valášek, Martin ; Münster, Petr (referee) ; Šifta, Radim (advisor)
The aim of this thesis is an explanation of the problem linear and nonlinear phenomena in optical access networks. In the first chapter refers to a description of the optical fiber, description of the optical environment and the main part is theoretical and mathematical description of phenomena that operate in optical fibers. It is therefore a specific attenuation, dispersion, phenomena of second and third-order, nonlinear light scattering and solitons. Then there is the dismantling brief overview of the distribution of access networks and their description. The second part deals with specific simulation of these phenomena in the simulation program OptSim 5.2. All connections will be implemented in the block diagram Sample-Mode, in which using appropriate units and setting the right parameters, we will try to confirm the theoretical assumptions of the first part.
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