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|???metadata.dc.title???: ||Numerical modelling of optical micro-cavity ring resonators for WDM networks|
|???metadata.dc.contributor.*???: ||Abujnah, Nabeil Abduljallil Abubaker|
|???metadata.dc.subject???: ||Wavelength division multiplexing|
|???metadata.dc.identifier.citation???: ||Abujnah,N. A. A. (2011) 'Numerical modelling of optical micro-cavity ring resonators for WDM networks'. Unpublished Ph.D. thesis. University of Glamorgan.|
|???metadata.dc.description.abstract???: ||Augmenting the level of integration for a lower cost and enhancing the performance of the
optical devices have turned out to be the focus of many research studies in the last few
decades. Many distinct approaches have been proposed in a significant number of researches
in order to meet these demands. Optical planar waveguides stand as one of vital employed
approach in many studies. Although, their low propagation loss, and low dispersion, they
suffers from high power losses at sharp bends. For this reason, large radius of curvature is
required in order to achieve high efficiency and compromise the high level of integration. For
the purpose of this research, in this thesis different ways to improve the performance of
optical microcavity ring resonators (MRRs) have been thoroughly investigated and new
configurations have been proposed.
The Multiresolution Time Domain (MRTD) technique was further developed and employed throughout this thesis as the main numerical modelling technique. The MRTD algorithm is
used as a computer code. This code is developed and enhanced using self built Compaq
Visual Fortran code. Creating the structure and Post-processing the obtained data is carried
out using self built MATLAB code. The truncating layers used to surround the computational
domain were Uniaxial Perfectly Matched Layers (UPML). The accuracy of this approach is
demonstrated via the excellent agreement between the results obtained in literature using
FDTD method and the results of MRTD.
This thesis has focused on showing numerical efficiency of MRTD where the mesh size
allowed or the total number of computed points is about half that used with FDTD.
Furthermore, the MRR geometry parameters such as coupling gap size, microring radius of curvature, and waveguide width have been thoroughly studied in order to predict and
optimise the device performance.
This thesis also presents the model analysis results of a parallel-cascaded double-microcavity
ring resonator (PDMRR). The analysis is mainly focus on the extraction of the resonant
modes where the effect of different parameters of the structure on transmitted and coupled
power is investigated.
Also, accurate analysis of 2D coupled microcavity ring resonator based on slotted
waveguides (SMRR) has been thoroughly carried out for the purpose of designing optical
waveguide delay lines based on slotted ring resonator (SCROW).
The SCROW presented in this thesis are newly designed to function according to the
variation of the resonance coupling efficiency of a slotted ring resonators embedded between two parallel waveguides.
The slot of the structures is filled with SiO2 and Air that cause the coupling efficiency to vary
which in turn control both the group velocity and delay time of SCROW structures results
from the changing the properties of the bent slotted waveguide modes which strongly
depends on the slot’s position.
Significant improvements on the quality factor and greater delay time have been achieved by
introducing sub-wavelength-low-index slot into conventional waveguide.|