Modeling and measurement of the modal properties of hollow core photonic-bandgap fibers
Abstract/Contents
- Abstract
- Hollow-core photonic-bandgap fibers (PBFs), which consist of an air core surrounded by a photonic-crystal array of air holes, have attracted significant attention due to their unique optical properties, and they have found interesting applications in sensing, nonlinear optics, and microscopy. The design and understanding of these fibers depend critically on our ability to model their optical properties accurately, a task made difficult by the complexity and very fine features (< 100 nm) of their internal structures. In this thesis, we developed two advanced codes to model several key modal properties of PBFs. The first one utilizes the finite-difference frequency-domain method to predict the modal dispersion diagram of the fiber, as well as the intensity profile, group-index spectrum, and group-velocity dispersion spectrum of the fundamental mode. This code implements two major innovations. First, it samples the fiber's index profile on a hexagonal grid to match the symmetry of the fiber and avoid digitization errors. Second, it uses as an input a realistic index profile of the fiber carefully constructed from SEM photographs to incorporate all observable structural deformations in the core and in the first two rows of cladding holes of the fiber (NKT Photonics' HC-1550-02 fiber). We demonstrate that the properties of the fundamental mode predicted by this code are in good agreement with their experimental counterparts measured in the laboratory. In a PBF the propagation loss and backscattering coefficient are dominated by random geometrical fluctuations of the fiber cross-section, which couple the fundamental mode to higher order modes. Modeling these two properties required first applying a strong perturbation theory to predict the amount of couplings induced by these perturbations, since the index difference between the two fiber materials (air and silica) is too high for a weak-perturbation approach. It also required developing a new physical and mathematical model of the core wall's surface roughness statistics. This model recognizes for the first time that the very small thickness of the core wall increases the wall roughness quite significantly, with the implication that the loss and backscattering are significantly higher than predicted by existing models. We show again good agreements between the predicted and measured values of loss and backscattering.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2013 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Zamani Aghaie, Kiarash |
|---|---|
| Associated with | Stanford University, Department of Electrical Engineering. |
| Primary advisor | Digonnet, Michel J. F |
| Thesis advisor | Digonnet, Michel J. F |
| Thesis advisor | Fan, Shanhui, 1972- |
| Thesis advisor | Solgaard, Olav |
| Advisor | Fan, Shanhui, 1972- |
| Advisor | Solgaard, Olav |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Kiarash Zamani Aghaie. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2013. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2013 by Kiarash Zamani Aghaie
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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