|
|
New trends in fibre optic sommunications
Lubajo, Lubajo Moses Wolyan ; Dejdar, Petr (referee) ; Münster, Petr (advisor)
Přenos optickych vláken je jednou z hlavních metod přenosu informací pro přenos na velké vzdálenosti. Byly vyvinuty různé modulační formáty pro maximalizaci informací přenášenych prostřednictvím komunikačního kanálu. Takové formáty sahají od formátů, které přenášejí jeden bit na symbol (jako je například binární fázové posunování klíčů, BPSK), a nebo vice, jako je například Kvadraturní fázové posunovací klíčování, duální polarizační kvadraturní fázové řazení a mnoho dalších ostatní modulace. Cílem diplomové práce je vytvořit a implementovat přenosovy systém s rychlostí 100 Gbps pomocí modulace formátu DP QPSK. Vysledky jsou shrnuty s ohledem na to, co bylo úspěšně implementováno, a zlepšení, která mohou byt ještě učiněna pro zvyšení přenosové vzdálenosti a snížení BER mimo jiné. Použitysimulační software je PHOTOSS.
|
|
|
Investigation of Fresnel rhomb
Jesenská, Eva ; Němec, Petr (advisor) ; Jakubisová, Eva (referee)
This bachelor thesis is devoted to the investigation of the polarization propertis of the Fresnel rhomb. First of all, we was interested in the quality of the polarized light which can be created using the Fresnel rhomb. In particular, we were checking the accuracy of the circular and linear polarization which is produced by Fresnel rhomb. Secondly, we tested the wavelength dependence of the quality of polarized light. We also investigated the dependence of the polarization state on the light angle of incidence. Finally, we compared the obtained results with those for the wave plates.
|
|
|
Usage of polarization multiplexing in optical access networks
Jakoubek, Petr ; Čučka, Milan (referee) ; Šifta, Radim (advisor)
This thesis reviews polarization multiplexing and its similarities, advantages and disadvantages to other types of multiplexing methods. The basics of optical fibers and its effects on transmission are discussed in terms of commonly used multiplexes. Additionally, divisions of optical access networks and multiplexing methods which could be used simultaneously with polarization multiplexing along with active and passive elements used for high-speed transmission such as polarization multiplex are described. Practical measurements of temperature influence to polarization and signal crosstalk in the amount of 70 °C and -40 °C are also included. The practical and theoretical measurements on 1 Gb signal led in G.652.D fiber for different situations are examined. Measurements containing 1 Gb signal includes test on triple play services (voice, video, data). First practical measurement on 1 Gb transmission shows how white noise, representing analog television, transmitted in the first polarization beam affects the signal in the second polarization beam. Second practical measurements show how two data streams transmitted through a single fiber at the same wavelength, but different polarization beams, creates a full duplex connection between two network elements. Results confirm the possibility on the usage of polarization multiplexing in optical access networks at common temperatures.
|
|
|
Polarization Imperfections of Light in Interferometry
Kučera, Petr ; Lazar, Josef (referee) ; Mohr, Fridemann (referee) ; Wilfert, Otakar (advisor)
Disertační práce pojednává o polarizačních nedokonalostech optických komponentů, které jsou využívány ke kontrole a k transformaci polarizačního stavu světla. Získané teoretické výsledky jsou pak využity ve vybraných aplikacích, jež ke své činnosti využívají právě polarizace světla. Konkrétně se jedná o zařízení měřící vibrace oscilujících objektů, dále o interferenční měření dvojlomu v transparentních materiálech a konečně, o vybraná témata z optické kvantové komunikace.
|
|
|
Nanometric vibrometry
Ševčík, Michal ; Schimmel, Jiří (referee) ; Škarvada, Pavel (advisor)
This thesis deals with the precise measurement of distances in nanometer range at ultrasonic frequencies for the purposes of vibrometry. The paper is primary focused on~nanometric displacement measurement methods. First the thesis deals with the physical phenomena based on light in the theoretical section. This includes interference of light, index of refraction, polarization, interferometry and more. Understanding of these physical laws is crucial for design and assembling of the interferometer. Subjects of interferometric method for precise and fast measurement of the nanometric displacement and vibration are discussed. Interferometer components such as lasers, photodetectors and optical elements are described are described in the final part of this section. Practical section of thesis can be divided into two parts. The design and assembling issues are discussed in the first section. Many problems which I had to solve are described. Control software and implementation of the signal processing is the subject of the second part. I met with particular problems such as phase unwrapping. I solved this problem of discontinuous phase field with user written algorithm. Finally the graphical user interface was created. Using assembled interferometer and written software application I measured vibration of Langevin transducer on ultrasonic frequencies.
|
guest ::
