Optical waveguide structures and devices are the fundamental basic building
blocks of photonic cireuits which play important roles in modern telecommunication and
sensing systems. With the fast development of fabrication technologies and in response to
the needs of miniaturization and fast increased functionality in future integrated photonic
chips, various structures based on high-index contrast waveguides, surface plasmonic
polaritons structures, etc., have been widely proposed and investigated. Modeling and
simulation methods, as efficient and excellent cost performance tools comparing to costly
facilities and time-consuming fabrication procedures, are demanded to explore and design
the devices and circuits before their finalization. This thesis covers a series of techniques for modeling, simulation and design of photonic devices and circuits with the emphasis of handling of radiation wave and the related power couplings. The fundamental issue in optical waveguide analysis is to obtain
the complete mode spectrum. In principle, we need the radiation modes to expand the
arbitrary fields of an open waveguide. In practice, however, the continuum nature of the
radiation modes makes them hard to use. The discrete leaky modes may approximately
represent a cluster of radiation modes under some circumstance and can be utilized in
mode expansion together with guided modes to significantly simplify the analysis of
mode coupling problems in optical waveguides. However, the leaky modes are
unbounded by nature and hence lack the usual characteristics of normal guided modes in
terms of normalization and orthogonality. Recently a novel scheme for handling of
radiation optical fields was proposed and demonstrated by applying perfectly matching layers (PML) terminated with a perfectly reflecting boundary (PRB) condition. In this
scheme, the radiation fields are represented in terms of a set of complex modes, some of
which resemble the conventional leaky modes and others associated with the interaction
between the PML media and the reflecting numerical boundaries. The mode spectrum is
therefore split into the guided modes and complex modes which possess the normal mode
features such as normalization and modal orthogonality. The seemingly paradoxical
application of both the PML and PRB in the new method has in fact overcome one of the
main challenges assoiated with this traditional method, i.e., the desire for discrete,
orthogonal, and normalized modes to represent radiation fields and the need for
elimination and reduction of spurious reflections from the edges of the finite computation
window. With the understanding of mode spectrum, a full vector mode matching method
and a complex coupled mode method for analyzing the wave propagation in optical
waveguides under the framework of PRL and PRB computation model have been
proposed. The methods have been validated through various structures such as waveguide
facet, polarization rotators, long/short period gratings etc. Then the proposed techniques
have been utilized to design a series of waveguide structures based on surface plasmonic
polaritons, slot waveguides etc. / Thesis / Doctor of Philosophy (PhD)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/21121 |
| Date | 04 1900 |
| Creators | Mu, Jianwei |
| Contributors | Huang, Wei-Ping, Electrical and Computer Engineering |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
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