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Sensor based on a fiber optic interferometer
Rozsypal, Filip ; Dejdar, Petr (referee) ; Čučka, Milan (advisor)
This diploma thesis deals with comparsion of 2x2 and 3x3 couplers. There is also description of issue of the Michelson interferometer and its use as a sensor. This sensor is very good at detecting vibrations. Part of the work is description of simulation of Michelson interferometer with 3x3 coupler as vibration sensor and localization of vibration on optical fiber by Michelson and Mach-Zehnder interferometer.
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Pulse Generator for Φ-OTDR in VPI photonics
Čučka, Milan
The paper focuses on Φ–OTDR (Optical Time Domain Reflectometry) systems which need short time duration and high powered pulses for proper function, because the backscattered signal is weak for proper detection. The article includes a simulation of the signal generator for Φ–OTDR sensoric systems in simulation software. Designed generator allows to try pulses, with different time of duration, pulse repetition frequency and power. The article also includes scientific notation of backscattered signal and a short description of the used systems.
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Optical fiber sensor based on Michelson interferometer
Kopáč, Ondřej ; Grenar, David (referee) ; Čučka, Milan (advisor)
This bachelor thesis deals with description and simulation of Michelson unbalance interferometer and description of fiber optic sensors. The simulation is realized by MatLab. The thesis also described basic optical phenomena, types of optical fibers and two types of interferometric detection. The thesis also deals with description of measurements and their results.
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Verification of stable next generation networks via transmission parameters measurement
Gregor, Lukáš ; Čučka, Milan (referee) ; Grenar, David (advisor)
This thesis deals with the measurement of transmission parameters in the new generation access networks NGA. The aim of the thesis is to build and configure a test network and scenarios for the measurement of service quality parameters and then verify the transmission stability. The theoretical part describes general functioning of NGN networks, the requirements of different telecommunications services on quality parameters, methodology and recommendations for measuring transmission parameters in packet networks. The practical part deals with the configuration of scenarios using mainly MPLS technology and methodology of their testing. Measurements were performed according to recommendations IETF RFC 2544, IETF RFC 6349 with the ExacTCP test and ITU-T Y.1564 with the EtherSAM test. For measurements were used measuring instruments of EXFO brand. In conclusion, the measurement results according to the mentioned standards were evaluated and also the advantages of using the measurement according to the given standard in NGA access networks were discussed.
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Processing of signals from fiber optic sensors
Sikora, Vojtěch ; Urban, František (referee) ; Čučka, Milan (advisor)
First two chapters of this paper deals with the division of optical fiber sensors, digital signal processing and includes price comparison of four experimental sensors. In chapter three analysis, description and evaluation of measurment has been demonstrated on Mach - Zehnder interferometer. Last chapter is about application for signal analysis from vibration sensors. Description contains snippets from source code and graphical user interface. This paper includes three fields - fiber optics, digital signal processing and creation of application - and thanks to them it provides solid basis for study of optic fiber sensors.
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Longitudinal index structures in optical fibers
Polreich, Štěpán ; Čučka, Milan (referee) ; Urban, František (advisor)
This thesis describes basic concepts, principles and properties of optical fibers. Considerable part is devoted to fiber gratings that are created by a change in the refractive index in the optical fiber core. In this work is described description, principle, method od production and distribution of gratings on Bragg gratings, gratings with long period and chirped gratings. In this thesis are also presented different types of lasers and their advantages over other lasers. A large part deals with the description of the femtosecond laser, with which the structures will be later made into the material. In addition, the laser modes are differentiated, this is a mode of micro-machining and modification or a change in refractive index of the material. The last part deals with change the refractive index in planar technology, the creation of a groove for fastening the fiber and attempts to write the gratings into the optical fiber. Created fiber sensor are tested for temperature and tensile changes. Finally, the practical use of sensors made by femtosecond laser and the advantages over UV laser and phase mask techniques are presented.
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Distributed fiber optic sensors
Holík, Tomáš ; Čučka, Milan (referee) ; Münster, Petr (advisor)
The thesis deals with the possibility of using optical fiber as a sensor. The introduction of the thesis is devoted to the foundations of optics. In addition, the thesis deals with optical interferometry, polarization and dispersion in optical fiber. The main output of the thesis is the comparison of acoustic vibration measurements using interferometric and polarization methods and further measurements on the real route in Brno.
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Location of vibration around the optical fiber
Dorazin, David ; Urban, František (referee) ; Čučka, Milan (advisor)
This diploma thesis solves possibilities of utilization optical fiber as sensor. At the beginning, basic division of this sensors is desribed, their principles and usage. Then the thesis is focused on distributed sensors based on the interference of the light, interferometers. This optic fiber interferometers are described, mainly their modifications for detection and localization of vibrations along optical fiber. Significant part of the thesis deals with dual Mach--Zehnder interferometer. This interferometer is theoreticaly desribed and simulated in Matlab. Further the thesis deals with development of two aplication in Matlab software. One application is for simulation and theoretical computation of dual Mach--Zehnder interferometer. Second application serves for signal processing of acquired data that are measured on this interferometer. At the end of the thesis, dual Mach--Zehnder interferometer is designed and build in laboratory enviroment and executed measurement and localization of vibrations using this interferometer.
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Measurement of polarized lightparametrs measurement on the optical-fiber sensor output
Drábek, Jakub ; Čučka, Milan (referee) ; Filka, Miloslav (advisor)
This master's thesis deals with the analysis of the optical power measurement using an optical fiber sensor. The thesis contains the theoretical background to understand the origin of polarization and its representation in space using Poincaré’s sphere and Stokes vectors. There is also a part describing optical performance measurement and the preview of analog measurements from various researches. Practical part focuses on verification of changes of fiber sensor parameters at temperature change in its surroundings and this part includes also additional suggestions for various types of measurements and verification of the function of the photodiode as an optical power transducer. Most measurements are based on the comparison of results obtained with the polarimeter. The results were plotted and discussed.
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