Thesis (M.S. in Applied Physics)--Naval Postgraduate School, December 2003. / Thesis advisor(s): Gamani Karunasiri, James Luscombe. Includes bibliographical references (p. 59-61). Also available online.

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Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: Dennis G. Deppe. Vita. Includes bibliographical references.

Plasmonics can be applied in a wide range of optoelectronic devices and it is induced by the interaction between incident light and conduction electrons. Resonance is induced by matching the photon energy and the frequency of electrons, which can cause the surface charge distribution and strengthens the electromagnetic field. Generally, plasmonics can be classified into surface plasmon resonance (SPR) and localized surface plasmon resonance (LSPR). SPR is the propagating wave, which occurs at interface between the dielectric and metal. LSPR is the non-propagating wave, which is the interaction between the metal nanoparticles (NPs) and incident light when the NP size is smaller than the light wavelength. In this thesis, plasmonic enhancement is studied to improve the performance of organic solar cells (OSCs) and light emission of organic semiconductors. OSCs are low cost, light weight, flexibility, and solution process ability at room temperature. Short exciton diffusion length limits the thickness of active layer, which causes low photon absorption and consequently low current generation. In this part, gold nanoparticles (Au NPs) are blended into OSCs to enhance photovoltaic performance. Au NPs can induce the localized surface plasmon resonance (LSPR) which enhances the light absorption due to electromagnetic field generation. Also, light can be trapped by scattering to increase the optical path and thus enhance the charge carrier generation. Film structure and 1D nanostructure of organic semiconductor are studied by their photoluminescence (PL) intensity. Generally, the PL intensity can be enhanced by SPR. Excitation energy can induce the surface plasmon (SP) instead of photon, which can amplify the spontaneous emission and stimulated emission. Compared to thin films, 1D organic structures achieve higher PL enhancement because they can trap the light more efficiently by Fabry-Pérot cavity. Different morphologies of organic semiconductor are synthesized and it is found that hexagonal plates can obtain better PL enhancement because of the Fabry-Pérot cavity mode. / published_or_final_version / Physics / Master / Master of Philosophy

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最近社會對計算密集型應用程序和高性能的多核計算系統的研究興趣增加。隨著每片芯片和計算資源的核心數量不斷增長的趨勢，更好的金屬互連或其他替代是至關重要的。這亦要滿足高帶寬，低功耗，細小體積和高擴展性的要求。ITRS的報告指出，兼容CMOS的矽光子光互連是一種替代，它符合上述要求，包括體積細少和只需納秒的開關時間，所以矽微環諧振器是具潛能被用為2×2開關元件來建立大規模集成光互連。 / 然而，微環互連的可擴展性可能受限制的，其中四個關注點包括總功耗，插入損耗，光功率不均勻和總串擾。2×2切換微環需要一定的功耗，而插入損耗也限制了每條切換路徑所經過的開關元件的數量。換句話說，開關元件在交互/直行狀態下的非相等損失限制了光互連的可擴展性。此外，在考慮滿足大型光互連的要求，光功率的不均勻性是一個重要的問題。最後，在每個2×2開關元件，輸出光功率洩漏對大型的光互連的輸出造成許多可能的串擾。這在輸出端口的總串擾是十分嚴重，它會減少微環互連的可擴展性。因此，本論文的目的著重於降低整體功耗，路徑的總插入損耗，每個輸出端口的光功率不均勻和每個輸出端口的總串擾。 / 在這篇論文中，我們首先回顧微環諧振器的結構和微環互連的背景。限制互連的可擴展性也將被討論。然後，我們將回顧以前的研究，致力於解決可擴展性問題。通過利用微環開關元件的不相等特徵，我們提出一個有效的模型以找到最佳的開關配置，來減少總功耗和每通道的平均插入損耗。此外，我們還提出一個快速的算法，以較短的計算時間減少交叉狀態開關元件數量。 / There is an increasing research interest on networks-on-chip architectures for growing computation-intensive applications and high-performance multi-core computing systems recently. With the growing trend of number of cores per chip and computation resources per chip, the advancement for conventional interconnections is essential to meet the demands of high-bandwidth capacity, low power consumption, compact footprint and high scalability. A report from ITRS pointed out that optical interconnections based on Complementary Metal Oxide Semiconductor (CMOS)-compatible silicon photonics is an alternative to conform to the above requirements. The carrier-injection-based silicon microring resonators is a promising candidate to build large-scale-integrated optical interconnections using 2×2 switching elements due to its very compact footprint and potential sub-nanosecond switching time. / However, the scalability of microring-based interconnection is limited by issues including power consumption, insertion loss, nonuniformity and crosstalk. Current technology for a 2×2 switching elements of microring requires non-negligible power consumption at cross/bar states on average. Intrinsic insertion loss also limits the number of successive switching elements per switching path. In other words, asymmetric loss characteristics of switching elements limit the scalability of optical interconnections. Also, the nonuniformity of optical power is an important issue to be considered in meeting the requirement of a large-scale optical interconnection. Last, as in each 2×2 switching element, there is an optical power leakage to the non-intended output-port and thus it creates many possible crosstalk powers at each output-port. This total crosstalk at output is severe and needs to be reduced for the scalability consideration of microring-based interconnection. Hence, the aim of this thesis focuses on the reduction in overall power consumption, average total insertion loss per path, average nonuniformity of optical power and total crosstalk at each output-port. / In this thesis we firstly review the background of microring resonator architecture and microring-based interconnections. The severe asymmetric behaviors limiting the scalability of interconnection are discussed. Then we review previous work dedicated to the scalability issues. By leveraging the asymmetric characteristics at cross/bar states of microring switching elements, we then propose an efficient model to find the optimum switching configuration for minimizing the total power consumption and the average insertion loss per path. Heuristics is also proposed to minimize the number of cross state switching elements with a shorter computation time. The results depict that the optimum average total insertion loss per path using 2B-SE achieve a 3.65-dB improvement for 128×128 switch size. The optimum average total insertion loss using 2B-SE in the worst-cast path is shown to be 7.2 dB less than the baseline values without optimization. Furthermore, simulation results show that regarding the nonuniformity in the worst case of the worst case, with the optimum switching configuration, the best improvement is 9.6 dB; the average improvement is 8.7 dB and the least improvement is 7.2 dB for 128×128 switch size. On the other hand, for the total crosstalk per path, simulation results show that the optimum switching configuration can achieve a 1.87-dB improvement for 128×128 switch size on average, compared with the average case without optimization. Also, the total crosstalk has a 2.43-dB improvement for 128×128 switch size in the worst case. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Yuen, Piu Hung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 48-51). / Abstracts also in Chinese. / Acknowledgement --- p.i / Abstract --- p.ii / 摘要 --- p.iv / Table of Contents --- p.vi / Table of Figures --- p.viii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Overview of microring resonators and microring-based optical interconnection --- p.2 / Chapter 1.3 --- Asymmetric characteristics of microring switching elements --- p.3 / Chapter 1.4 --- Problem statement --- p.5 / Chapter 1.5 --- Motivation of this thesis --- p.6 / Chapter 1.6 --- Outline of this thesis --- p.7 / Chapter Chapter 2 --- Previous work on optimization of microring-based interconnection --- p.9 / Chapter 2.1 --- Introduction --- p.9 / Chapter 2.2 --- A previous scheme for insertion loss reduction --- p.10 / Chapter 2.3 --- A previous scheme for nonuniformity reduction --- p.12 / Chapter 2.4 --- Prior work on power consumption in optical networks --- p.14 / Chapter 2.5 --- Prior work on crosstalk in optical cross-connect networks --- p.16 / Chapter 2.7 --- Summary --- p.17 / Chapter Chapter 3 --- Optimization scheme of microring-based interconnection configurations for reduction of power consumption and insertion loss --- p.19 / Chapter 3.1 --- Introduction --- p.19 / Chapter 3.2 --- Principle of determining the optimum switching configurations --- p.20 / Chapter 3.2.1 --- Calculations of power consumption and insertion loss --- p.23 / Chapter 3.3 --- Heuristic for reduction of power consumption and insertion loss --- p.24 / Chapter 3.4 --- Simulation results and discussion --- p.27 / Chapter 3.5 --- Summary --- p.32 / Chapter Chapter 4 --- Optimization scheme of microring-based interconnection configurations for the reduction of nonuniformity and crosstalk --- p.33 / Chapter 4.1 --- Introduction --- p.33 / Chapter 4.2 --- Principle of determining the optimum switching configurations --- p.34 / Chapter 4.2.1 --- Calculation of nonuniformity --- p.35 / Chapter 4.2.2 --- Calculation of crosstalk --- p.36 / Chapter 4.3 --- Simulation results and discussion --- p.39 / Chapter 4.4 --- Summary --- p.42 / Chapter Chapter 5 --- Conclusion and Future Work --- p.44 / Chapter 5.1 --- Conclusion of this thesis --- p.44 / Chapter 5.2 --- Future work --- p.46 / List of Publications --- p.47 / Bibliography --- p.48

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references (leaves 60-66). Available also in a digital version from Dissertation Abstracts.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: limiting amplifier; optic receiver; shunt peaking; transimpedance amplifier. Includes bibliographical references (p. 97-100).