الفهرس 
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Abstract
A novel design for dispersion compensation based on dual core liquid crystal photonic crystal fiber (DC-LCPCF) is reported and analyzed. The new structure is based on optical coupling between the dual cores of the suggested PCF. The full vectorial finite element method (FVFEM) is used to study the dispersion characteristics of the DC-LCPCF. A very large negative chromatic dispersion of 27101.8 ps/(nm-km) is achieved at λ =1.542 μm with circular air holes only. Additionally, the proposed PCF has good tunability with the temperature. Further, the coupling can be switched between transverse electric (TE) and transverse magnetic (TM) modes through external electric field due to the infiltration of the liquid crystal (LC) material. In addition, the DC-LCPCF with elliptical air holes has an ultra-high negative dispersion of 289118 ps/(nm-km) at λ = 1.543 μm. This thesis is organized as follows: Chapter 1 introduces the topic of dispersion and the motivation and objective behind this work. Chapter 2 outlines the signal degradation in optical systems. In addition, the different types of dispersion are defined and the ways to mitigate their effects are discussed. It also introduces the concept of CD and how both the material and the waveguide dispersion are combined to yield the total CD in the optical fiber. Moreover, different types of dispersion compensation techniques are discussed and how to use them in optical transmission systems. Chapter 3 surveys the numerical methods for modeling the behavior of PCFs with the concentration on the FVFEM and explains its basic idea and applications. Chapter 4 presents the proposed design of DC-LCPCF developed in this thesis for dispersion compensation. It describes the implementation and design simulation of the suggested design. It also discusses the results obtained by varying air-hole diameters and the position of the NLC-filled ring. The effect of temperature and molecules rotation angle ϕ is also explored. Moreover, the chapter introduces additional three new designs using elliptical air holes to obtain high birefringence with higher negative dispersion values. Further, the available fabrication methods of the proposed structure are described. The chapter ends with a comparison between the obtained results and the previously published results in this field. Finally, Chapter 5 concludes the thesis with a summary, and few suggestions for the future scopes of this work.