|
|
Assesment of the meaning of Polarization Mode Dispersion
Červenka, Vladimír ; Rampl, Ivan (referee) ; Kyselák, Martin (advisor)
This thesis describes the most important types of distortions in fibre optics during transmission. They are divided into two main groups, linear and nonlinear. The linear phenomena consist of internal and external attenuation, different kinds of dispersions and negative effect of signal noise. The special attention is focused on polarization mode dispersion. The impact of the nonlinear phenomena on fibre optics in high date rate is discussed as well. Furthermore, the negative effects in fibre optics and their causes are deeply analyzed on results gathered from simulation of some transmission lines. There are presented many methods for counting the meaning of polarization mode dispersion, for example the theoretical model including implementation on physical layer and reducing power looses. Some examples of designing fibre optic lines are introduced along with calculation for them.
|
|
|
The impact of polarization mode dispersion on error-rate of optical fibre link
Dorociak, Petr ; Křivánek, Vítězslav (referee) ; Kyselák, Martin (advisor)
Master’s thesis engages in the impact of polarization mode dispersion on optical communication system. Polarization mode dispersion is mathematically described by Stoke’s and Jone’s space and ensure the theoretic causes of the rise of polarization mode dispersion that are divided on the external and internal effects. On the basis of these effects grow up a differential group delay (DGD) which makes causes that individual polarization modes have between them a time delay and limitation of maximum bit rate. Then master´s thesis analyses the influence of the polarization mode dispersion on the pulse enlargement and on the modulation signal. In this work, there are described the most applicated optical modulation formats. Polarization mode dispersion has also influence on the bit error rate of optical fibre link and closing of eye diagram too. Eye diagram is used to view the transmission characteristics and diagnoses the channel errors. Eye diagram is connected with the definitions as a bit error rate (BER) and signal-to-noise ratio (SNR) that are explained in this work too. Following the gained experiences it was designed an useful graphic interface to display the effect of the polarization mode dispersion on the transmitted signal. Realization of the graphic interface is created in the program MATLAB. In Matlab-Simulink are created six models according to the kind of modulations with characteristic AWGN (Additive White Gaussian Noise) channel. Program was tested for a typical values. In all calculations it is counted only with the losses that are caused by the polarization mode dispersion. It is not calculated with the losses that are caused by a chromatic dispersion and attenuation. At the end of this work are evaluated all types of modulation formats depending on the polarization mode dispersion, optical fibre length, price and complexity of the realization. Atteined results of my master’s thesis are compared with two foreign articles.
|
|
|
PMD - polarization mode dispersion and its effects on data transport
Trávníček, Pavel ; Dostál, Otto (referee) ; Filka, Miloslav (advisor)
My graduation thesis is concerned with the effect of polarization mode dispersion on transmitted signal by optical line. It describes external and internal causes of origination of polarization mode dispersion. On the basis of these effects there is a differential group delay (DGD). It is the time delay in meantime within individual modes. DGD results in a time extension of impulsion and limitation of maximum bit rate. This thesis contains localization methods of part of gossamer filament with increased value of PMD by POTDR method. This method is based on the principium of back dispersion and its modifications SOP a DOP. Very important chapter of this thesis is the measurement of the polarization mode dispersion. There are described methods of PMD measurement. It is the interferometric and polarimetric method and the method of state of polarization. The major part of this thesis is about the reduction of polarization mode dispersion effect. This part is divided into two parts. First part is about the methods of PMD effect reduction and the second one is about the PMD compensation. The discrepancy between these two parts is the reduction way of PMD effect on transmitted channel. The compensation use the compensation components inserted into the transmission path. By PMD reduction methods we can solve the problems from the view of changing of fibre or all cable. For better understanding of polarization mode dispersion effect there are simulated 4 optical lanes of various parameters. The simulation output is the eye diagram which provides the view at results of transmission lane. In the final part there is the evaluation of measured parameters of optical lanes simulated in a laboratory.
|
|
|
Use of optical fiber as a temperature sensor
Procházka, Jakub ; Škorpil, Vladislav (referee) ; Filka, Miloslav (advisor)
This diploma thesis is focused on use of polarization mode dispersion for measurement of temperature. It also deals with representation of polarization mode dispersion in Poincaré sphere and a mathematical description of polarization mode dispersion by using Stokes and Jones vectors. Here are described basic alternatives of settings, selected temperature relationships and dependence and relationship between coherency and polarization. The practical portion of the diploma thesis examines behavior of the temperature sensor at different temperatures for wavelength 1550 nm and 633 nm.
|
|
|
The Optical Fibre Dispersion Effects on Multiplex Transmission Systems
Kyselák, Martin ; Filka, Miloslav (advisor)
This doctoral thesis deals with present trend to turn up the bit rate of the optical fibres making use of wavelenght multiplex systems. There are new theoretical and practical problems caused by the new technologies. Except the known modal dispersion there exist problems caused by chromatical and polarization mode dispersion. In the opening of the thesis the known effects, which influence the payload signal, are introduced. The polarization mode dispersion has the main attention. Within the scope of this thesis there has been programmed the statistical calculator which can analyses the measured values of differential group delay by Monte Carlo calculation. Next meaningful output is the designating application of the optical routes. It is possible to mathematicaly unambiguously define the polarization mode dispersion by Jones, Stokes and Poynting vectors. This complicated calculations are mechanized and in the simulation application make possible to simulate the signification of the PMD influence at different input parameters. The thesis includes the study of the PMD modulation format impact with the results of simulations and confrontation with other scientists results. The significant output are the final practical results examinations, which can be implemented thanks to the possibility of using the FTB-5500B measuring device.
|
|
|
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.
|
|
|
Dispersion effects in high-speed optical networks
Filip, Tomáš ; Šporik, Jan (referee) ; Tejkal, Vladimír (advisor)
This bachelor’s thesis is focusing on optical transmission principal, its transfer mediums and furthermore also with focusing on its advantages and disadvantages. First half of this thesis focuses on adverse influences, which affect signal transmission in optical networks, on dispersion influences, especially on Polarization Mode Dispersion (PMD). Second half of this thesis deals with measuring of properties of optical fibers, largely chromatic and polarization mode dispersion, used methods and its principals. Furthermore, there are mentioned current compensation possibilities. The seventh chapter deals with optical route simulation in OptiSystem and testing chosen compensation methods for bit rate 40Gb/s. In the last chapter there are elaborated results of real optical route measurements for Masaryk University.
|
|
|
Design of Graphic Interface for Calculation of Differential Group Delay
Vohralík, Jan ; Křivánek, Vítězslav (referee) ; Kyselák, Martin (advisor)
The Bachelor's thesis is aimed to the problems regarding Polarization mode dispersion in optical fibre. Polarization mode disperzion limits the bandwidth of high speed comunication system. It cases a differential group delay between different polarizatins. If the delay is too high than the bits overlap and a bit error rate is increased. The work include description of polarization in Jones space and Stokem space. For description of Polarization mode disperzion is used PMD vector. I demonstrate influence of differential group delay in optical fibre at special grafic program develop in C# language.
|
|
|
Measurement and evaluation of dispersions in optical fibre
Očenášek, Jan ; Čučka, Milan (referee) ; Vojtěch, Josef (advisor)
This semestral project deals with measurement and evaluation of the dispersion in the optical fiber. Introduction of the work is focused on the description of the principle of optical fiber and optical environment. Another part is devoted to a detailed description of polarization mode dispersion - PMD, including the causes of which are divided into internal and external. Because of these impacts of the differential group delay DGD, which results in time delay of each polarization modes to each other and hence to reduce the transmission speed. Polarization mode dispersion is one of the most limiting factors for the realization of high-speed optical transmission, so in the next section describes the measurement and compensation of PMD effect.
|
|
|
Temperature Dependence of PMD
Drábek, Jakub ; Hanák, Pavel (referee) ; Münster, Petr (advisor)
Bacherol thesis describes the problems of polarization mode dispersion-PMD. Size of the delay PMD is a random variable that varies in time. When operating at high data rate communication links is one of the major problem of the optical fiber. PMD value affects many different environmental influences as temperature, and therefore the measurement of PMD become standard in deploying high-speed optical networks.
|
guest ::
