الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The Photonic crystals (PCs) are periodically structured electromagnetic media, generally possessing photonic band gaps that inhibit the existence of light within the crystals in certain wavelength range. There are three types of PCs, one-, two-, or three-dimensional PC structures. The photonic crystal fiber (PCF) which is studied in this dissertation is an example of the use of two dimension PC structures with a wide range of applications. In the last few years, the PCFs have attracted great attention in both research and industrial environment due to their uncommon optical properties which cannot be achieved by the conventional optical fiber such as single mode behavior over a wide wavelength range, and large effective mode area. This thesis concerns with modeling and designing the PCF and its applications to polarization rotator (PR), directional coupler, polarization splitter, and multiplexer-demultiplexer (MUX-DEMUX). The present study can be subdivided into the following parts: 1- New and an accurate full vectorial finite difference - artificial neural network approach is presented for reducing the computational time, overcoming meshing problems of the finite difference method and accurately predicting the various mode properties of PCFs. 2- 2- A new design of highly birefringent PCF with low losses for the two polarized modes is presented and studied using the proposed approach. Moreover, the structure is tailored to obtain a flat dispersion over a wide range of wavelengths with high birefringence. 3- This dissertation also presents the modal analysis results of a novel design of high birefringence soft glass PCF infiltrated with a nematic liquid crystal (NLC-PCF). The analyzed parameters are the effective index, birefringence, dispersion, effective mode area, nonlinearity, and confinement losses for the two fundamental polarized modes. In addition, due to their different uses in communication systems, the performance and beam propagation analysis of novel designs of high tunable PR, directional coupler, polarization splitter, and MUX-DEMUX based on the soft glass NLC-PCF are reported thoroughly. Moreover, the fabrication tolerance for each proposed design is investigated.