This thesis is an exploration of the properties of engineered defects in self-assembled photonic crystals, with particular attention paid to the complete band gap of the a-Si inverse opal. The potential of this metamaterial for optical signal processing in telecommunications is studied using a pair of complementary simulation techniques; one is a frequency-domain code, while the other is in the time domain. Calculations of photonic states associated with isolated point defects are performed, and their cavity modes, losses and field distributions are calculated. The equivalence of two classes of defects is demonstrated, and a robust, single-mode point defect microcavity is proposed. A linear defect waveguide, comprised of coupled chain of such point defects, is analyzed. Transmission around sharp bends is demonstrated, and some simple devices are considered. Several potential approaches to fabrication of the defects, the properties of various candidate materials, and more complex devices are discussed.

This thesis is an exploration of the properties of engineered defects in self-assembled photonic crystals, with particular attention paid to the complete band gap of the a-Si inverse opal. The potential of this metamaterial for optical signal processing in telecommunications is studied using a pair of complementary simulation techniques; one is a frequency-domain code, while the other is in the time domain. Calculations of photonic states associated with isolated point defects are performed, and their cavity modes, losses and field distributions are calculated. The equivalence of two classes of defects is demonstrated, and a robust, single-mode point defect microcavity is proposed. A linear defect waveguide, comprised of coupled chain of such point defects, is analyzed. Transmission around sharp bends is demonstrated, and some simple devices are considered. Several potential approaches to fabrication of the defects, the properties of various candidate materials, and more complex devices are discussed.

Nanophotonics is an emerging research field that deals with interaction between light and matter in a sub-micron length scale. Nanophotonic devices have found an increasing number of applications in many areas including optical communication, microscopy, sensing, and solar energy harvesting especially during the past two decades. Among all nanophotonic devices, three main areas, namely photonic crystals, optical metamaterials and plasmonic devices, gain dominant interest in the photonic society owning to their potential impacts. This thesis studies the fabrication and characterization of three types of novel devices within the above-mentioned areas. They are respectively photonic-crystal (PhC) surface-mode microcavities, optical metamaterial absorbers, and plasmonic couplers. The devices are fabricated with modern lithography-based techniques in a clean room environment. This thesis particularly describes the critical electron-beam lithography step in detail; the relevant obstacles and corresponding solutions are addressed. Device characterizations mainly rely on two techniques: a vertical fiber coupling system and a home-made optical transmissivity/reflectivity setup. The vertical fiber coupling system is used for characterizing on-chip devices intended for photonic integrations, such as PhC surface-mode cavities and plasmonic couplers. The transmissivity/reflectivity setup is used for measuring the absorbance of metamaterial absorbers. This thesis presents mainly three nanophotonic devices, from fabrication to characterization. First, a PhC surface-mode cavity on a SOI structure is demonstrated. Through a side-coupling scheme, a system quality-factor of 6200 and an intrinsic quality-factor of 13400 are achieved. Such a cavity can be used as ultra-compact optical filter, bio-sensor and etc. Second, an ultra-thin, wide-angle metamaterial absorber at optical frequencies is realized. Experimental results show a maximum absorption peak of 88% at the wavelength of ~1.58μm. The ultra-fast photothermal effect possessed by such noble-metal-based nanostructure can potentially be exploited for making better solar cells. Finally, we fabricated an efficient coupler that channels light from a conventional dielectric waveguide to a subwavelength plasmonic waveguides and vice versa. Such couplers can combine low-loss dielectric waveguides and lossy plasmonic components onto one single chip, making best use of the two. / QC 20110524

Optical devices based on Planar Lightwave Circuit (PLC) technology have well been studied due to their inherited advantages from Integrated Circuits (IC), such as: small size, high reliability, mass production and potential integration with microelectronics. Among all the materials, silicon nanowire platform gains more and more interest. The large refractive index difference between core and cladding allows tremendous reduction of the component size. This thesis studies theoretically and experimentally some integrated optical devices based on silicon nanophotonic platform, including echelle grating demultiplexers and photonic crystals. Some of the numerical methods are introduced first. Scalar integral diffraction method is efficient for calculating the diffraction efficiency of gratings. Beam propagation method and finite-difference time-domain method are also introduced, for simulating the light propagation along the devices. The fabrication technology and characterization methods are described. The fabrication steps involve: plasma assisted film deposition, E-beam lithography, RIE-etching. All these steps are proceeded under cleanroom environment. The characterization is mainly based on two methods: end-fire coupling and vertical grating coupling. The grating coupler is more efficient compared with the butt-coupling between fiber and nanowires, but is worse solution for final packaging. Two types of components have been realized and characterized with the above technology. The echelle grating demultiplexer is one of the key components in WDM networks. A method for increasing the diffraction efficiency based on total internal reflection is applied, and a significant improvement of the diffraction efficiency of more than 3dB is achieved. A novel cross-order echelle grating-based triplexer, a bidirectional transceiver for application in the Passive Optical Networks (PON), has been designed and fabricated, which can multi/demultiplex three channels located at 1310nm, 1490nm and 1550nm. Polarization dependence issue of echelle grating demultiplexers has been studied. Two polarization compensation schemes have been proposed, which are for the first time polarization insensitive designs of echelle grating demultiplexers based on silicon nanowire platform. Photonic crystal devices are also addressed in the thesis. There has been little research on the photonic crystal cavity based on pillar type. A silicon pillar type photonic crystal cavity has been fabricated with the measured Q value as high as about 104, and with an extremely high sensitivity for the changing of the background material or the effective diameter of the pillars. This kind of structure has the advantage on sensing applications compared to the air-hole type structure. / QC 20100820

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 111-116).

Thesis (D.Eng.) - University of St Andrews, June 2009.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 201-208). Also available in electronic version.

Thesis (Ph.D.) - University of Queensland, 2006. / Includes bibliography.

Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2007. / Papapolymerou, John, Committee Member ; Adibi, Ali, Committee Member ; Citrin, David, Committee Chair ; Summers, Christopher, Committee Member ; Voss, Paul, Committee Member.

Thesis (Ph.D.) -- McMaster University, 2004. / Adviser: Wei-Ping Huang. Includes bibliographical references (leaves 168-176).