Band Gap Analysis and Light Propagation Properties of Two Dimensional Photonic Crystals
Date Issued
2004
Date
2004
Author(s)
Chiu, Ming-Hui
DOI
zh-TW
Abstract
The purposes of this thesis are two fold. First, the band structure of two-dimensional photonic crystals is investigated. By using plane-wave method, we calculate the band structure of two-dimensional photonic crystals in a square array with dielectric rods. The bandwidth and the central frequency of the photonic band gap can be controlled by changing the size and the dielectric constant of the inclusions for the TM mode, but no band gap occurs for the TE mode. We also investigate the properties of resonant modes which arise from introducing local defects in photonic crystals. The resonant frequencies and resonant modes can be controlled by changing the dielectric constant and the size of the defects. The field distributions of the resonant modes are determined by using a finite-difference time-domain method with perfectly matched layer absorbing boundary condition. By removing one row of rods, the photonic crystal waveguide with a single guided mode inside the gap can be created. The light wave at frequencies in the gap is confined inside the guide, and travels with low loss energy around 90∘bends.
A multichannel wavelength division multiplexing system and a direct-ional coupler with two-dimensional photonic crystals are proposed in the second part of the thesis. The WDM filter can be created by consisting of a line defect waveguide and frequency selective microcavities. In our simulation, we show the ability to filter an incident pulse to four channels with bandwidth 0.003(ωa/2πc). And by constructing two nearby line defects, a directional coupler can be created. With properly designed coupling length, we can transfer the power from one waveguide to another.
Subjects
時域有限差分法
光子晶體
分波多工器
方向耦合器
光波導
Photonic Crystals
FDTD
Waveguide
Directonal Coupler
WDM
Type
thesis
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