M.Ing. / In recent years, many research and development projects have focused on the study of fibre Bragg gratings. Fibre Bragg gratings have been used in the field of sensors, lasers and communications systems. Commercial products that use fibre Bragg gratings are available. On the other hand, in the field of software development, object-oriented programming techniques are also becoming very popular and powerful. The focus of this work is on solving fibre Bragg grating problems by a simulation program with object-oriented programming techniques. For fibre Bragg grating problems, widely used theories and numerical methods such as the coupled-mode theory and the transfer matrix method will be applied in the analysis, modelling and simulation. The coupled-mode theory is a suitable tool for analysis and for obtaining quantitative information about the spectrum of a fibre Bragg grating. The transfer matrix can be used to solve non-uniform fibre Bragg gratings. Two coupled-mode equations can be obtained and simplified by using the weak waveguide approximation. The spectrum characteristics can be obtained by solving these coupled-mode equations. The optical numerical libraries of fibre Bragg gratings have been built by using object-oriented techniques. The code was realized by C++ and Object Pascal language in the Delphi4, C++ Builder4 and Visual C++6 environment. The compiled binary files and the code of the simulation program are available for both the end user and program developer. This simulation program can be used to analyze the performance of sensors and communication systems that use fibre Bragg gratings. Uniform, chirped, apodized, discrete phase shifted and sampled Bragg gratings have already been simulated by using the direct numerical integration method and the transfer matrix method. The reflected and transmitted spectra, time delay and dispersion of fibre Bragg gratings can be obtained by using this simulation program. At the same time, the maximum reflectivity, 3dB-bandwidth and centre wavelength can also be obtained. This thesis consists of three parts. The first part introduces a suitable theory and modelling that have been used to analyze the characteristics of fibre Bragg gratings. Secondly, the codes of the modelling are realized by the suitable programming languages in different development environments. Finally, this simulation program is utilized to analyse real physical problems with fibre Bragg grating applications.
|27 February 2009
|South African National ETD Portal
Page generated in 0.002 seconds