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Optical signal detection and maesurement of low deflections using the Michelson interferometer
Kováč, Petr ; Hudcová, Lucie (referee) ; Křivák, Petr (advisor)
The dissertation is concerned with the description and utilization of interference of two coherent optical rays. In addition, the conditions of coherence and its connections with the occurance of interference are discussed. Michelson's interferometer is used for the practical utilization of the interference effect. The possibility of measuring relatively small changes is demonstrated - deviation of piezocrystal, measurement of the coherent length of optical source and measurement of the index of refraction of tramsparent materials. The manner of optical coherent detention and its utilization in optical communication systems is indicated. After demonstration of the principle was carried out the measuring of detection of optical signal modified by the external modulator.
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Measurement and simulation of lenses and concentrators optical parameters
Filip, Martin ; Hudcová, Lucie (referee) ; Křivák, Petr (advisor)
Optics is branch, whis is deal with generation, propagating and detection of optical radiation. There is big boom of optical links in last years, thanks to originate of laser, fiber cable with low attenuation and production of semiconductor optical components. Besides fiber cables there are used also free space optics links. These links are used especially for build fast computer network between buildings, whose distance is up to 1 km. We need to know properties of used optical elements for creation this link so that we get the biggest possible gaim on a reciever detector. We are focusing on measurement of optical properities lenses, which are used for forming optical beam in free space optics link.
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Program for the optical link power budged calculation
Kováč, Martin ; Hudcová, Lucie (referee) ; Křivák, Petr (advisor)
Goal of this work is to study methodic of designing optical fiber and wireless link and to program an application which will be able to calculate power budget of specified link. Power budget of the link is the most important part of designing an optical fiber or wireless link because it tells us if it’s even possible to realize such connection or how many optical repeaters and amplifiers are needed. The bachelor thesis has three parts. The first part describes designing of optical fiber link (limitation by attenuation and dispersion) and various components that are needed (laser diode, optical fiber etc.). The second part describes designing of optical wireless link and atmospheric transfer environment (attenuation by beam spreading, attenuation by atmosphere and by turbulences in atmosphere). And finally the third part which is realization of the program for the optical link power budget calculation in compiler C++ Builder 6, flowchart, used equations and pictures (how does the application look like, how is it controlled and how the output may look like).
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Optical transmitter design
Vraspír, Marek ; Křivák, Petr (referee) ; Hudcová, Lucie (advisor)
This work dissert on proposal of optical ampifier excitor for transmission of information using optical enviroment. For proposition was chosen suitable transmission enviroment and LD diode that is used in optical communications. Accent was put at universal using of diode. Than was solved the modulation of input signal, it is used the „on-off“ keying, which is proceeded by integrated circuit, which is designed for none extreme transmission speeds. The work contains the solution of the potection of electrical circuit and LD diode against high current and thermal influences in transmitter.
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Program for the free space optical link power budged calculation
Vaculík, Jakub ; Hudcová, Lucie (referee) ; Křivák, Petr (advisor)
With increasing demands for transit capacity of data networks as well as communication network optical networks seem to be the suitable solution. Light beam is attractive to use for data transmission . Transmitted data can be expressed by means of light impuls.. For execution of the project we need the whole optical telecommunical system which consists of transmitter, transmission link and receiver. The target of transmission link is to transfer optical beam from its resourse to detector with minimal losses. The optical fibre or optical freespace optical link FSO are used for this purpose. Connection to internet by optical fibre is out of reach for most households and plants, it is very expensive and so far it isn´t in the offer of network operators and service providers. (at lest in our condition). But there is still the posibility to obviate optical fibre networks and reach high permeability and safety of communication by means of freespace optical links. It is much easier to implement, but only for short distance. FSO enables quick and even ecological communication which is in the world of more famous radio frequency networks very pleasant message.
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Steam boiler with grate firing burning wheat straw
Křivák, Petr ; Kohout, Přemysl (referee) ; Lisý, Martin (advisor)
The aim of the thesis is the design of the steam grate boilers of 40 t/h for straw burning. The required parameters are generated steam temperature 420 ° C and a pressure of 5.5 MPa. The specified fuel is cereal straw with a calorific value of 9.5 MJ/kg. The calculation is made from the stoichiometric calculation of elemental analysis, to calculate the individual dimensions and heating surfaces of the boiler.
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Semiconductor laser driver for 1Gbit/s
Chlachula, Filip ; Křivák, Petr (referee) ; Prokeš, Aleš (advisor)
This master´s thesis deals with a solution of the driving circuits of semiconductor laser. In the beginning of the thesis there is an analysis of semiconductor lasers and its characteristics. Then the principle of laser diodes and its excitation is described. This thesis is focused on semiconductor laser excitation through the use of direct and modulating current. Several circuits are described, designed and simulated. The best resulting circuit is realized and measured in the laboratory.
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Electronic informative board
Kakáč, Tomáš ; Křivák, Petr (referee) ; Diblík, Jan (advisor)
This thesis dealt with concept of electronic informative board. The board is connected PC via USB. Data are converted from USB using converter to input microprocessor. These data are processed and displayed on graphic lcd display. During bachelor's thesis we're resumed with realization electronic informative board. We used a microcontroller from Atmel. Futher, we required a real-time circuit from manufacture Epson. For the imaging unit we used a graphic LCD display from copany Powertip. Following the design we compiled and revived a hardware part of the device. After a succesfull revive, we compiled a program for microcontroller. It was written in programming language C, with use of compiling enviroment AVR studio 4.
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Long Range Free Space Optical Links
Křivák, Petr ; Vlček, Čestmír (referee) ; Vašinek, Vladimír (referee) ; Wilfert, Otakar (advisor)
This dissertation thesis deals with a long range free space optical links for communication over the distance of few tens of kilometers in the atmosphere. The problematic of the beam propagation and atmospheric effects influencing the beam and the quality of the communication protocol are discussed. The measuring link is also designed to study the parameters of the communication link work conditions. The measuring link consists of two heads. The transmitter head is designed to use two optical beams with laser diodes at the wavelength of the atmospheric windows 850 or 1550 nm and the overall power of hundredths of mW. The receiver head includes the Fressnel lens. For the detection of very weak signal, the avalanche photodiode is used. In the end of this work, due to the high power of the transmitting optical beam, the laser safety conditions are also discussed, including the deduced optical transmitters construction recommendations.
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