Abstract
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.