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Angular velocity sensor with Sagnac interferometer
Skalský, Michal ; Beneš, Petr (referee) ; Havránek, Zdeněk (advisor)
This thesis deals with theoretical description of fiber-optic angular velocity sensors, or gyroscopes, and further with design and construction of own sensor of this type. The theoretical part describes problematics of interferometric and resonant fiber-optic gyroscopes. Basic principles and physical limits are described for both types. The main focus is then put on analysis of possible conceptions of these sensors. Solutions using different optical configurations as well as various modulation and signal processing schemes are discussed. The practical part deals with design and construction of own interferometric fiber-optic gyroscope in closed-loop configuration. The gyroscope utilizes all-fiber components including piezoelectric phase modulator and unexpensive single-mode fiber, which are commonly used only for open-loop configurations. To realize closed-loop operation, special modulation scheme based on fully harmonic signal was develeped, which yields linear output within wide dynamic range. This type of modulation requires high level of synchronization achieved by using a field-programmable gate array module. The gyroscope utilizes powerful broadband fiber source, polarizer and Lyot depolarizer which ensure good reciprocity of whole architecture. The parameters of the sensor, obtained by measurement, are even comparable to some sensors using PM fiber, which is much more expensive.
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Acoustic fields visualization using laser interference
Raffay, Tobiáš ; Havránek, Zdeněk (referee) ; Skalský, Michal (advisor)
This bachelor thesis is focused on solving the visualization of acoustic waves using laser interference. The necessary theoretical knowledge to understand the used method of schlieren photography are summarized in the theoretical part. The practical part describes the implementation and results of the assembled systems, shows the differences, and solves the problems that occurred during testing. Apart from visualization of acoustic waves, we can also observe the flow of gases and air with small changes of refractive index.
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Angular velocity measurement with fiber optic interferometer
Skalský, Michal ; Šedivá, Soňa (referee) ; Havránek, Zdeněk (advisor)
This thesis deals with general theoretical description, design and construction of sensor of angular velocity based on Sagnac interferometer, or interferometric fiber-optic gyroscope. The theoretical part is focused firstly on explanation of basic principles and finding important formulas. Secondly, some state-of-the-art configurations of the fiber-optic gyroscope and their differences are analysed. Limiting factors and parasitic effects are also described. Attention is also paid to properties and suitability of particular optical components. The practical part especially deals with an utilization of common low-birefringent optical fiber in an fiber-optic gyroscope. Firstly, some basic properties of components and the simplest configurations of gyroscope were tested. They provided an important knowledge for design of final solution working in an open loop configuration with phase modulation. Further, specific components used in this demonstration sensor and its construction are described in more detail. Designed gyroscope utilizes all-fiber components made of common low-birefringent fiber so this solution is unexpensive. It uses an unpolarized light and depolarizer to ensure stability. Another specificity is a light source using spontaneous emission of erbium-doped fiber. Finally, some basic parameters of designed gyroscope acquired by measurement as well as record of calibration are stated.
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Fiber-optic liquid level sensor
Ondra, Dominik ; Beneš, Petr (referee) ; Skalský, Michal (advisor)
This text summarizes scientific principles that are used in fiber optics field, and could be used to design liquid level sensor. Different types of optic fibers and advanced optic structures are analyzed for liquid level sensor usage. Mechanisms of already existing types of optic fiber liquid level sensors and other mechanism liquid level sensors are characterized. Three sensor designs are proposed. One working with different levels of auttenaution when bending the fiber. The other meassuring different refraction indexs of the environment and the last one based on phase delay of light. Viabillity of these principle has been tested. Text also describes optic fiber splicer Fujikura FSM 100P+ and optic fiber sturctures that it is able to produce. Sensor based on refraction index of environment has been calibrated.
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Measurement system for determination of the piezoelectric charge coefficient
Kašpárek, Ondřej ; Skalský, Michal (referee) ; Fialka, Jiří (advisor)
The master's thesis deals with methods of measuring material coefficients of piezoelectric materials with a focus on direct methods of measuring piezoelectric charge constant. The first chapters of this paper focus on the theory of the piezoelectric effect, the description of piezoelectric material coefficients, and the theory of direct measurements of piezoelectric charge constant, where is the generated charge, which corresponds to the mechanical load, measured. The next part of this thesis deals with designing and creating advanced measuring systems based on the quasi-static method, which are measuring the electrical response of the material to a step-change in force or a harmonic force signal straining the testing sample. In the last part, the influences on the measurement results, such as the use of electromagnetic shielding, are investigated using the created measurement systems.
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Measurement of sound fields using non-contact optical methods
Karásek, David ; Skalský, Michal (referee) ; Havránek, Zdeněk (advisor)
The purpose of this paper is to assemble measurement chain dedicated to contactless measuring of acoustic fields emitted by test sources and to validate its results. At first author discusses possible optic methods which can be used to measure acoustic fields, then he talks about theoretical foundations which are needed to measure data and to reconstruct final data. The last two chapters are dedicated to cover basics about created program and to analyse various aspects which influence measured and reconstructed data. Created measurement chain is fully functional, at the end of this thesis are proposed some ways of improving
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Invasive pest species in fruit crops in the Czech Republic
Holý, Kamil ; Stará, Jitka ; Kocourek, František ; Ouředníčková, Jana ; Skalský, Michal ; Pultar, Oldřich
The publication summarizes the basic information about invasive pest species in fruit orchards, spreading to our country since 2000. Information about morphology, similar species, area of origin, distribution in Europe and Czechia, risk of introduction, life cycle, host plants, methods of monitoring and control, are provided for each pest species.
Fulltext:  PDF
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Measurement system for determination of the piezoelectric charge coefficient
Kašpárek, Ondřej ; Skalský, Michal (referee) ; Fialka, Jiří (advisor)
The master's thesis deals with methods of measuring material coefficients of piezoelectric materials with a focus on direct methods of measuring piezoelectric charge constant. The first chapters of this paper focus on the theory of the piezoelectric effect, the description of piezoelectric material coefficients, and the theory of direct measurements of piezoelectric charge constant, where is the generated charge, which corresponds to the mechanical load, measured. The next part of this thesis deals with designing and creating advanced measuring systems based on the quasi-static method, which are measuring the electrical response of the material to a step-change in force or a harmonic force signal straining the testing sample. In the last part, the influences on the measurement results, such as the use of electromagnetic shielding, are investigated using the created measurement systems.
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Fiber-Coupled Fabry-Pérot Interferometric Sensor: Analysis And Modelling
Skalský, Michal
This paper presents a theoretical analysis of the Fabry-Pérot interferometric sensor utilizingan extrinsic fiber-optic cavity. Its behavior is modelled and simulated for various conditions,showing the key properties of the different sensor’s setups. The simple single-mode sensing tip andthe GRIN collimator are compared. Further, new kind of sensing head is proposed exhibiting aninverse reflectivity and enabling a theoretical resolution less than 1 pm.
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Acoustic fields visualization using laser interference
Raffay, Tobiáš ; Havránek, Zdeněk (referee) ; Skalský, Michal (advisor)
This bachelor thesis is focused on solving the visualization of acoustic waves using laser interference. The necessary theoretical knowledge to understand the used method of schlieren photography are summarized in the theoretical part. The practical part describes the implementation and results of the assembled systems, shows the differences, and solves the problems that occurred during testing. Apart from visualization of acoustic waves, we can also observe the flow of gases and air with small changes of refractive index.
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