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Extension of optical fiber transmission system
Horský, Tomáš ; Tomašov, Adrián (referee) ; Dejdar, Petr (advisor)
The diploma thesis describes the elaboration of a program for the simulation of an optical transmission path. The work introduces the basic parameters of optical transmission, such as attenuation, dispersion and bandwidth. Furthermore, the techniques of line code and error detection are described in the work, especially a cyclic redundancy sum. The key parameter of this thesis is dispersion of the optical signal. The work includes the characteristics of the eye diagram and its analysis. The resulting program can also be used to measure the real transmission route and its parameters.
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Advanced analysis of moving objects in transport
Hora, Adam ; Dejdar, Petr (referee) ; Kiac, Martin (advisor)
This thesis solves the problem of monitoring objects from live streams or camera recordings. The aim is also to create your own data set usable in solving traffic situations and analysis for object recognition and classification. The YOLO method with OpenCV support was used for evaluation purposes. The result is a program in which road recordings can be inserted or live broadcasts can be used from a camera positioned so that it captures the road. The output of the program is to find out the number of motor vehicles at any given moment and the average number of vehicles that were on the road during given periods of time. The videos from which the data set is created were provided by the thesis supervisor. The main benefit of this work is the ability to monitor traffic density at given time intervals.
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Fiber joints and their protection
Galovič, Dominik ; Dejdar, Petr (referee) ; Münster, Petr (advisor)
The bachelor thesis deals with the issue of optical fiber joining. The theoretical part describes the methods of optical fiber splicing, protection of optical splices and possible errors that affect the quality of the optical splice. Also described are methods for measuring important optical joint parameters, such as attenuation or reflection attenuation. An important part of the work is a description of the restoration of primary protection of spliced fiber. The theory is further applied in the practical part, where the attenuation of the optical links was measured using the mentioned methods. It also includes a comparison of the mechanical strength of optical splice and a joint formed by optical connectors. This knowledge is then applied in a proposal for minimizing the optical splice and proposals for restoring the primary protection of the optical splice was described.
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Implementation of optical fibers with FBG elements into technical textiles
Zaytsev, Vsevolod ; Dejdar, Petr (referee) ; Münster, Petr (advisor)
(This bachelor thesis aims at a theoretical analysis of \acs{FBG} (\acl{FBG}), its use in telecommunications technology and the design of smart textiles based on FBG filters. The theoretical part of this work discusses the knowledge of FBG, their production and use, presents an overview of technical textiles and the current state of the market. Then the question of adhesive adhesives will also be described. The practical part is devoted to the design of smart textiles and the subsequent measurement of the dependence of the wavelengths of the built-in FBGs on their temperature.)
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Smartphone application for optical fiber monitoring system
Vaverka, Jan ; Myška, Vojtěch (referee) ; Dejdar, Petr (advisor)
The main goal of this master thesis is to develop a multi-platform mobile application in the Flutter framework for iOS and Adnroid platforms. The application will remotely communicate with a fiber optic monitoring system through a server. In the introduction of the thesis, the issues of fiber optics and fiber optic security options are described. The next section describes the communication options between the application and the server, also the Flutter framework is described. In the practical part, the communication between the application and the server is proposed. A large part of the practical section is focused on the design and programming of the multiplatform application. The last part is focused on testing the communication between the application and the server.
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Fiber-Optic Sensors
Dejdar, Petr ; Róka,, Rastislav (referee) ; Kyselák, Martin (referee) ; Münster, Petr (advisor)
Optical networks are continuously expanding and this creating space for the use of optical fibers for non-data transmissions. One of them is the use for sensing purposes, where optical fibers can be used to measure temperature, pressure, vibration, etc. In standard conditions or in conditions where the placement of conventional sensors is not suitable (increased humidity, radiation, lack of space, etc.).This paper is devoted to the comparison of technologies comparing sensing systems and describes their principle and their possible applications. Subsequently, the different systems are built and tested. Possible improvements are then proposed based on the measurements, where for the reflectometric system the advantages of using edge detection algorithms are quantified. For the polarization detectors, improvements are made using machine learning classification algorithms with classification success rates above 97 %. Detailed measurements of the sensitivity of optical fibers to acoustic vibrations in three different environments, with different path configurations, cables, vibration-damping materials, etc. are also described. These measurements proved the possibility of intercepting optical fibers using interferometric, reflectometric, and polarization systems, where the polarization system is proven to be the least sensitive and records only lower frequencies. Based on these measurements, a system for securing the physical layer of optical networks is then proposed, which is able to accurately distinguish the quiescent and cable manipulation states from the datasets we created.
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Optical fiber polygon for testing of services
Frolka, Jan ; Horváth, Tomáš (referee) ; Dejdar, Petr (advisor)
Bachelor’s thesis describes the types of optical fibers, their structures and properties. The basic parameters of optical fibers and standards for single-mode fibers are defined. The differences between the various connectors and the polishing of the ferrules are also described. The next section describes the multichannel transmission technology and its modifications, as well as the FFTx technology. In the next part, the work deals with measurements on optical fibers, the most common measurement methods are listed. The reader will learn what to do and also what not to do when manipulating with optical elements. The attached diagrams show the test polygon, as well as the measured and calculated values of the attenuation of its parts.
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Fiber optic perimeter intrusion detection systems
Duisenbekova, Karina ; Dejdar, Petr (referee) ; Münster, Petr (advisor)
Tato bakalářská práce se zaměřuje na aplikaci optických vlaknových senzorů v perimetrickém zabezpečení s cílem zabránit neoprávněnému přístupu a intruzi. Tyto systémy dokážou rozlišovat různé typy vloupání a narušení, čímž zvyšují bezpečnost chráněných objektů. Teoretická část práce popisuje dva prototypy senzorů - distribuované akustické a interferometrické senzory. Praktická část se opírá o Mach-Zender interferometrický optický vlaknový senzor, jehož citlivost je testována skákáním a chůzí poblíž senzorových kabelů.
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Quantum cryptography
Turčanová, Klára ; Dejdar, Petr (referee) ; Münster, Petr (advisor)
The bachelor thesis focuses on quantum cryptography. In the theoretical part, there is an analysis of secure key distribution in the fiber-optic infrastructure. Methods such as quantum key distribution (QKD) or physical layer secret key generation for fiber-optic networks are analyzed, including a description of the security and technical limitations of the methods. The thesis also attempts to interpret some basic principles of the optic infrastructure used in QKD. In addition to the distribution of keys, the thesis also tries to approximate the basic principles of the optic infrastructure used in QKD and, last but not least, post-quantum cryptography (including a comparison with quantum cryptography and current protocols). In the practical part, the effect of the macrobending of the fiber and the reflectivity of the connectors on the operation of the quantum system was demonstrated. It was also demonstrated that temperature and light acting on the QKD optic infrastructure do not have a fundamental effect.
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