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- Type of Document: M.Sc. Thesis
- Language: Farsi
- Document No: 41495 (05)
- University: Sharif University of Technology
- Department: Electrical Engineering
- Advisor(s): Mehrany, Khashayar
- Abstract:
- The Bragg reflection mechanism is in this thesis employed to design optical fibers with specific characteristics. First, optical Bragg fibers (BF) with radial periodicity are considered and optimized to have the minimum leakage loss by introduction of a new parameter referred to as the point-wise wave-number. In this fashion, the optical effects of geometrical factors of the to-be-designed fiber are brought together in the point-wise wave-number and the sought-after parameters of the fiber are thus analytically found. Despite a few approximations made in extraction of optimum parameters, rigorous numerical analysis of the here-proposed optical BF clearly demonstrates that it outperforms conventional Bragg fibers. The pointwise wave-number is then employed to design a highly nonlinear optical BF. To this end, miscellaneous criteria are proposed and examined to assess the strength of optical nonlinearity. It is shown that maximizing the imaginary part of the Bloch wave-number is the best criterion for analytical optimization of highly nonlinear BFs. Finally, Bragg mechanism in the longitudinal direction is considered and a novel approach is proposed to extract eigenmodes of fiber Bragg gratings (FBG). This approach can be easily extended to be used for analysis of longitudinally periodic BFs. This type of modal analysis is quite useful in nonlinear applications where the linear field profile is usually desired for applying the perturbation theory
- Keywords:
- Modal Analysis ; Perturbation Theory ; Fiber Bragg Grating (FBG) ; Bragg Fiber ; Leakage Loss ; Effective Area
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