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Polarization sensitivity of the fibre optics grating sensors
Babieska, Lukáš ; Šifta, Radim (referee) ; Urban, František (advisor)
This diploma thesis deals with the effect of full-length fixation of optical fiber gratings on their polarization dependence. In addition, the effect of primary protection and parameters of optical fiber gratings on their intrinsic polarization dependence was also investigated. The theoretical part of the thesis briefly describes the historical development of optical fiber gratings, the types of optical fiber gratings used and also describes in detail the principles of polarization dependence of optical fiber gratings and the mechanisms of polarization dependence of optical fiber gratings. In the practical part of the thesis, suitable measurement methods for measuring the polarization dependence of optical fiber gratings are proposed. Furthermore, these methods are optimized and used for subsequent measurements of the effect of fixation on the polarization dependence of optical fiber gratings. Many different methods of fixation of the optical fiber gratings were then used to measure the effect of fixation, and the degree of polarization dependence of the optical fiber gratings was evaluated for each of the different fixation methods. The practical part of the thesis is concluded with a detailed summary of the results obtained.
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Design of optical fiber temperature sensor for detection of defense perimeter
Zámečník, Ondřej ; Grenar, David (referee) ; Filka, Miloslav (advisor)
This diploma thesis deals with the issue of measuring the ambient temperature using a~single-mode optical fiber used as a temperature sensor. The thesis describes the basic knowledge about polarized light, its propagation in optical fiber and describes special fibers that preserve polarization. It also deals with the representation of polarization states on a Poincaré sphere and the use of Stokes and Jones vectors. In the practical part, several selected methods of optical signal supply to the temperature sensor are measured. Subsequently, the suitability of the given methods is evaluated from the measured results and the courses are compared with the records measured from real routes. This thesis aims to select a suitable connection of a temperature sensor for a long route of optical fiber and verify its functionality.
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Polarization mode dispersion
Turský, Aleš ; Dostál, Otto (referee) ; Filka, Miloslav (advisor)
The work deals with dispersive effects of single mode fibers. We learn about the chromatic dispersion, the main attention is paid to the Polarization Mode Dispersion. We clarify the root cause origin of the Polarization Mode Dispersion describing parameters and its effect on transmitted data. Further on, the works dedicates to measure methods of the Polarization Mode Dispersion which is the interferometric method or the POTDR method. We explain the ways of the PMD removal at contemporary optic routes and options of PMD compensation by using compensators of various types. There is also mentioned the possibility of profiting from the soliton transmission. The last chapter deals with measuring of a real optic route. It includes measured data and its evaluation due to the ITU-T demands.
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Utilization and Suppression of Birefringence Phenomena in Optical Fiber Sensory Applications
Motúz, Rastislav ; Hudcová, Lucie (referee) ; Vlček, Čestmír (referee) ; Drexler, Petr (advisor)
The thesis deals with integral and distributed optical fiber sensors of electric current. In the area of integral sensors the analysis is performed by Jones matrix calculus and the simultaneous influence of induced circular and undesired linear birefringence using an ortho-conjugation retroreflector. Furthermore, the proposed conjugation loop variant using half-wave phase retarders is analyzed. The theoretical conclusions are confirmed by simulation and experimental measurement. In the field of distributed fiber optic sensors, analysis and simulation for the detection of plasma currents in thermonuclear fusion reactors, based on the POTDR technique, is performed. An improvement procedure is proposed for circular-shaped vacuum vessel reactors. Plasma current detection procedure in divertor-type reactors have been newly designed and simulated to investigate the effect of the OTDR detector noise on plasma current detection accuracy.
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Transmission Broadband Channel Implementation Using Light Propagation Polarization Axes
Mafka, Martin ; Münster, Petr (referee) ; Filka, Miloslav (advisor)
The aim of this master’s thesis is to analyze ways of propagation light in optical fiber with two polarization planes. Theoretical part is focused to to the issue of polarized light, its mathematical description using Stokes and Jones vectors, the state of polarization on Poincare sphere and polarization multiplex. In the practicle part are first measured several laboratory measurements to verify the theoretical assumptions from the previous chapters. At the end of the thesis was constructed a functional polarization multiplex for wavelength 1550 nm.
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Effect of Light Polarization on Optical Fibre Links
Obručník, Ondřej ; Křivánek, Vítězslav (referee) ; Kyselák, Martin (advisor)
The bachelor thesis deals with the emergence of polarization mode dispersion, its mathematical expression and also the influence, which polarization mode dispersion has on the optical communication channel. First, the chapters birefringence in fibers and polarization debate its emergence and basic characteristics, then are introduced two possibilities of mathematical expression polarization mode dispersion namely in Stokes and Jones space, whence is more closely examine Jones space. End work adverts about dependencies wavelength and birefringence on differential group delay, also about using fibre Bragg gratings in optical fibres and fall of characteristics grating on differential group delay.
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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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Fibre optic vibration detection
Vlková, Monika ; Münster, Petr (referee) ; Dejdar, Petr (advisor)
The main focus of this bachelor thesis is the measurement of the polarization state during the manipulation of telecommunication infrastructure in order to secure the physical layer. The theoretical part is devoted to optical sensors. More specifically, optical vibration sensors working on the principle of several methods including OTDR, FBG, interferometry and polarization are discussed. The types of polarized light and possible methods of polarization are also described. The practical part of this thesis focuses on the measurement of the polarization state in an optical fiber. Measurements have been performed for a total of three different AD convertors. Using the measured data, the quality of the convertors was then compared and evaluated. The final output of this thesis is an annotated dataset for automatic event detection purposes.
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