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Testing of optical networks
Šimoník, Jan ; Horváth, Tomáš (referee) ; Filka, Miloslav (advisor)
The aim of this bachelor thesis is to describe testing of optical networks physical layer by norms and recommendations (CSN, ITU and RFC). The first chapter provides a description of the individual optical fibers, their division and a brief description of each type. In the next part of this thesis, the methods and procedures for testing the various parameters of optical networks are described, according to specific standards and recommendations. The issue of testing quality of services is also described, primarily focused on triple play services, which are operated at optical access networks. The following is a description of the issue of access and transport networks, a draft of methodology for testing the physical layer of these networks is given. In conclusion, there is a chapter describing the practical measurements made on a passive optical network. In the annexes of this thesis the limit parameters of optical fibers used for the measurements and draft of the content for measuring protocol are listed.
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Simulation of Mach Zehnder interferometer
Rozsypal, Filip ; Münster, Petr (referee) ; Čučka, Milan (advisor)
This bachelor thesis deals with the simulations of Mach-Zehnder and Michelson interferometer. These simulations are realized by VPIphotoncs and MatLab. The thesis also describes the optical and physical phenomena, the usage and the principle of operation of interferometers and results of measurements with validation of the basic work of both interferometers.
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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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Microbending fiber optic sensors
Švestka, Jiří ; Štohl, Radek (referee) ; Šedivá, Soňa (advisor)
This thesis deals with the influence microbending the transmitted signal at the bare optical fiber. Microbending influence on the transmitted signal is investigated in this work by changing the weight, power and water level in the tank by using this test fixture. The results of the experiments are proposed to enter the laboratory tasks to measure the impact microbending the transmitted signal in the subject line fiber-optic sensors (MOES).
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Measuring methods of key parameters in optical networks
Balon, Jiří ; Reichert, Pavel (referee) ; Tejkal, Vladimír (advisor)
The main goal of the master’s thesis was to familiarize with optical networks dilemma and its measuring during fabrication. The whole thesis is divided into several parts where the first part deals with optic fiber dilemma. It describes its kinds, properties and also suggests a basic principle of optic signal dispersion using these fibers. It describes also optical network FTTx architecture (Fiber To The x). The second part of the thesis focuses on methods of measuring key parameters of optical networks. Is brings out the methods of measuring optical loss and dispersive influences. The last and final part in focused on creating a methodical manual for measuring these networks during its fabrication and verifying measuring methods stated in the theoretical part inside a real network. Measuring was implemented on an optical network of Masaryk University in Brno.
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Coaxial cables in communication networks
Hotárek, Lukáš ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
The semestral thesis is focused on coaxial cables, its development and current utilization. In the prologue of this paper, the history and origin of the cable is described with mentioning important dates and events in its development. Since the coaxial cable is type of metallic cable, part of the paper deals with the theory, parameters and characteristics of metallic cables. The theory of all basic types of metallic cables is described, that implies twisted pair, structured cabling and coaxial cable, to which is dedicated most space. The next chapter presents brief description, basic division and utilization of fiber optic to enable comparison with coaxial cable. It presents main advantages and disadvantages as well as reasoning for prevalence of use of optic fibers. The current use of coaxial cable is presented. Aside from cable television, computer and telephone networks, the coaxial cables are also used as feeder lines for transmitting and receiving aerials and as television aerial lead. Due to great possibility of utilization of coaxial cables exists a broad spectrum of cables with different parameters and properties. Therefore a separate chapter focuses on particular types of cabling, describes its significant parameters and practical utilization. The last part of the paper presents parameters of coaxial cables that can be verified and that bear great importance in praxis. The methods of proper measurement are mentioned. Aforesaid parameters include impedance, cable loss and distance-to-fault. Described are also modern analyzers that are most commonly used for measuring said parameters of coaxial cables and aerials.
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Design of a mirror collimator for a light beam outgoing from a silica fibres bundle of a circular cross section.
Vodák, Jiří ; Brillová, Kateřina (referee) ; Ohlídal, Miloslav (advisor)
Imaging spectroscopic reflectometry is an innovative method for studying optical properties of thin layers. This method allows as studying large areas of thin layers. Imaging spectrophotometer designed in The Institute of Physical Engineering was supposed to allow measurements along areas of about 25 mm x 25 mm. However this area was not achieved. To achieve desired dimensions of the area under study it is necessary to redesign the optical transmission setup between a source of monochromatic light and the imaging spectrophotometer.The old spectrophotometer design consists only of a mirror collimator not sufficient enough to collimate a rectangle shaped light beam on the output of the monochromator. The new design will consist of optical cable of silica fibers transforming the rectangle input light beam into a light cone which will be easier to collimate by a mirror collimator.
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NG - PON technologies
Balon, Radek ; Dostál, Otto (referee) ; Filka, Miloslav (advisor)
The main object of the master thesis was to familiarize with optical networks, describe the latest current technology of passive optical networks and create a simple simulation of our chosen technology. This thesis was divided into several parts. The first part deals with passive network architecture. I illustrated the basic functional elements which are present in optical networks. I described the active elements and principles of data transmission in the distribution network. To conclude this chapter I described the different standards that are defined for the passive network. In second part I familiarized myself with key parameters and their adverse effect on the transmitted signal. Another part deals with the new technologies that are defined for the next generation of passive network NG-PON. I described the principles of data transmission in these networks and their advantages and disadvantages. The last part deals with creating custom simulations of technology defined by standard NG-PON using OptSim 05.02 Subsequently I have collated all the results of the various technologies and show the advantages and disadvantages of each.
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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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