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Simulations were carried out to determine the optical properties of 2 different layer structures which have been used in quantum well intermixed devices. The supported modes, effective refractive indices and optimal device dimensions prior to intermixing were reported. 1.5 micrometer ridge waveguides with 600 micrometer bend radii are shown to be suitable for minimizing loss. A first approximation to the intermixed structures were also simulated. An Asymmetric Mach-Zehnder Interferometer (AMZI) fabricated using a sputtered SiO2 Quantum Well Intermixing (QWI) process was also characterized. A 100 GHz channel spacing with an extinction ratio up to 16 dB was observed. Tuning of the device was achieved using current injection. A 0.45 nm tuning range was achieved at 15 mA of injected current. The design of a monolithically integrated all optical binary half-adder is also presented, with physical dimensions based on the results of the previous simulations.

This Masters thesis examines Raman enhancements in Liquid Core Waveguides for the purpose of studying dilute solutions of Colloidal Nanoparticles.

An SOI-based platform designed for wideband coupling of light from optical fibers to a 50 nm wide plasmonic slot waveguide is described in this thesis. The device is based on a newly proposed orthogonal junction with coupling efficiencies above 70% near the telecom wavelength. To construct the coupling platform, two such junctions are utilized for input and output, where Si wires are place 90 degree with respect to each of the two ends of a plasmonic section. Analytic studies and FDTD simulations have demonstrated attractive properties such as a smooth micron-wide transmission spectrum that can be spectrally shifted with the design parameters, and the natural phase-matching between the dielectric and plasmonic sections consequent of the waveguide orientations. Fabrication procedures and proof-of-concept characterization work are also presented. The experimentally-tested platform with its unique features would enable applications in on-chip sensing and plasmonic slot-based waveguiding at the 50 nm scale.

Simulations were carried out to determine the optical properties of 2 different layer structures which have been used in quantum well intermixed devices. The supported modes, effective refractive indices and optimal device dimensions prior to intermixing were reported. 1.5 micrometer ridge waveguides with 600 micrometer bend radii are shown to be suitable for minimizing loss. A first approximation to the intermixed structures were also simulated. An Asymmetric Mach-Zehnder Interferometer (AMZI) fabricated using a sputtered SiO2 Quantum Well Intermixing (QWI) process was also characterized. A 100 GHz channel spacing with an extinction ratio up to 16 dB was observed. Tuning of the device was achieved using current injection. A 0.45 nm tuning range was achieved at 15 mA of injected current. The design of a monolithically integrated all optical binary half-adder is also presented, with physical dimensions based on the results of the previous simulations.

This Masters thesis examines Raman enhancements in Liquid Core Waveguides for the purpose of studying dilute solutions of Colloidal Nanoparticles.

An SOI-based platform designed for wideband coupling of light from optical fibers to a 50 nm wide plasmonic slot waveguide is described in this thesis. The device is based on a newly proposed orthogonal junction with coupling efficiencies above 70% near the telecom wavelength. To construct the coupling platform, two such junctions are utilized for input and output, where Si wires are place 90 degree with respect to each of the two ends of a plasmonic section. Analytic studies and FDTD simulations have demonstrated attractive properties such as a smooth micron-wide transmission spectrum that can be spectrally shifted with the design parameters, and the natural phase-matching between the dielectric and plasmonic sections consequent of the waveguide orientations. Fabrication procedures and proof-of-concept characterization work are also presented. The experimentally-tested platform with its unique features would enable applications in on-chip sensing and plasmonic slot-based waveguiding at the 50 nm scale.

Photonic circuits can transmit data signals in a much higher speed thanconventional electronic circuits. However, miniaturization of photonic circuitsand devices is hindered by the existence of light diffraction limit. A promisingsolution to this problem is by exploiting plasmonic systems for guiding andmanipulating signals at optical frequencies. Plasmonic devices are generallycomposed of noble metals and dielectrics, whose interfaces can confine surfaceplasmon polaritons, a hybrid wave that is free of diffraction limit. Plasmonicwaveguides and devices are serious contenders for achieving next-generationphotonic integrated circuits with a density comparable to the electronic counterpart. This thesis addresses the design issues of passive plasmonic devices whichare critical for realization of photonic integration, including plasmonic waveguides,splitters, couplers, and resonators, investigated with both the finitedifferencetime-domain method and the finite-element method. In particularwe present, firstly, a coupler which efficiently couples light between a silicondielectric waveguide and a hybrid plasmonic (HP) waveguide. A coupling efficiencyas high as 70% is realized with a HP taper as short as 0.4μm. Theexperimental result agrees well with the numerical simulation. Secondly, wenumerically investigate and optimize the performances of 1×2 and 1×3 HPmultimode interferometers (MMIs), which split light from a silicon waveguideto multiple HP waveguides. Total transmission over 75% can be achieved inboth cases. Thirdly, we study the coupling and crosstalk issues in plasmonicwaveguide systems. Several methods for crosstalk reduction are proposed.Finally, HP nanodisk micro-cavities are designed and are numerically characterized.With a radius of 1μm, a high quality factor of 819 and a highPurcell factor of 1827 can be simultaneously achieved, which can be useful forrealizing efficient nano-lasers. / QC 20110523

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2008. / Includes bibliographical references (leaves 82-93). Also available in electronic version.

Thesis (M. Phil.)--University of Hong Kong, 1998. / Includes bibliographical references (leaves 91-92).