Animals have evolved diverse strategies to control solar and thermal radiations so that they can better adapt to their natural habitats. Structured materials utilized by these animals to control electromagnetic waves often surpass analogous man-made optical materials in both sophistication and efficiency. Understanding the physical mechanism behind these structured materials of nature inspires one to create novel materials and technologies. Our optical and thermodynamic measurements of insects (Saharan silver ants and cocoons of the Madagascar comet moth) living in harsh thermal environments showed their unique ability to simultaneously enhance solar reflectivity and thermal emissivity, and to maintain a cool body temperature. Saharan silver ants, Cataglyphis bombycina, forage on the desert surface during the middle of the day. The ants’ conspicuous silvery glance is caused by a coating of hairs with unique triangular cross-sections. The hair coating enhances not only the reflectivity of the ant’s body surface in the visible and near-infrared range of the spectrum, where solar radiation culminates, but also the emissivity of the ant in the mid-infrared. The latter effect enables the animals to efficiently dissipate heat back to the surroundings via blackbody radiation under full daylight conditions. The fibers produced by the wild comet moth, Argema mittrei, are populated with a high density of air voids that have a random distribution in the fiber cross-section but are invariant along the fiber. These filamentary air voids strongly back-scatter light in the solar spectrum, which, in combination with the fibers’ intrinsic high emissivity in the mid-infrared, enables the cocoon to function as an efficient radiative-cooling device, preventing the pupa inside from overheating. The reduced dimensionality of the random voids leads to strong optical scattering in the transverse direction of the cocoon fibers. This enables tightly confined optical modes to propagate along the fibers via transverse Anderson localization. We made the first observation of transverse Anderson localization in a natural fiber and further demonstrated light focusing and image transport in the fibers. This discovery opens up the possibility to use wild silk fibers as a biocompatible and bioresorbable material for transporting optical signals and images. Drawing inspirations from these discoveries, we designed and developed high-throughput fabrication processes to create coatings and fibers with passive radiative-cooling properties. The radiative-cooling coatings consist of various nanoparticles imbedded within a silicone thin film. The sizes and materials of the nanoparticles were chosen to provide simultaneously high solar reflectivity and thermal emissivity. The coating has been implemented in two site studies on real roofs and has demonstrated reduced roof temperature by up to 30oC in the summer and associated reduction of electricity usage by up to 30%. We also made biomimetic fibers from regenerated silk fibroin and a thermoplastic using wet spinning. Spectroscopic measurements showed that these man-made fibers exhibit exceptional optical properties for radiative-cooling applications.

石墨烯，由單層碳原子緊密排列成蜂巢狀的晶體結構，擁有卓越的電學性能和光學性能。這些優異的性能包括：極高的電子遷移率，超寬的吸收光譜，栅電壓調控光躍遷性質，飽和吸收性質。石墨烯的獨特光學性質已經被用來製造多種高性能的光電器件，包括光電探測器， 飽和吸收器， 光調製器和四波混頻的介質。同時，石墨烯的製造工藝可以與現代半導體標準製造工藝相兼容， 加上它穩定的化學性質， 石墨烯非常有潛力在未來半導體工業發展中發揮重要作用。 / 單層石墨烯可以透過97.7% 垂直入射的光，吸收2.3% 左右，並且吸收的光頻非常寬。雖然對於單層碳原子結構，這個吸收率很大，但是在一些器件中，我們需要更高的光吸收率。爲了突破單層石墨烯光吸收的極限，一種可行的辦法是延長石墨烯與光相互作用的長度。將單層石墨烯轉移到長的硅波導上，可以延長石墨烯與光作用的長度。除了線性光吸收特性，石墨烯的飽和吸收特性也有廣泛的應用。很多脉衝激光發生器是利用被動鎖模的原理，即激光器中的飽和吸收器將連續的光波轉變成頻率固定的脉衝。石墨烯已經被證明是恢復速度快、調製範圍大的飽和吸收器。 但是，石墨烯和硅波導結合作為飽和吸收器的特性和它們的應用還從來沒有被研究過。 / 在論文中，我們研究了石墨烯轉移到硅波導后的線形光學性質和飽和吸收特性。首先我們討論了石墨烯轉移的方法，然後我們通過實驗調查了石墨烯在貴波導上的線形光學性質和飽和吸收特性。爲了研究石墨烯/硅波導在被動鎖模光纖激光器中的作用，我們利用石墨烯/硅波導作為飽和吸收器製造了一個光纖激光器。之後，通過在激光腔體中加入可调滤波器， 我們用成功的演示了波長可調製被動鎖模光纖激光器。 / 多脉衝激光光源在光纖通信，測量學和光學器件性能鑒定中有重要作用。所以研究緊湊、穩定並且價格實惠的多脉衝鎖模激光器非常有意義。爲了實現多脉衝鎖模光纖激光器，我們將硅基濾波器和石墨烯/硅波導集成在一起. 在論文中，我們設計并優化了能被應用於多脉衝鎖模激光器的寬帶寬濾波器凹凸光栅。 / Graphene, a single 2D sheet of carbon atoms arranged in a honeycomb lattice, has superior electrical and optical properties including extremely high charge-carrier mobility, broadband optical absorption, gate-variable optical transitions and saturable absorptions. Its unique optical properties have led to a range of promising optoelectronic devices, such as photo detectors, saturable absorbers, optical modulators and nonlinear media for four-wave mixing. Graphene’s complementary metal-oxide-semiconductor (CMOS) integration processes at wafer scale and its electrochemical stability make it a promising candidate for post CMOS electronics. / Monolayer grapheme transmits 97.7% of the normal incident light and absorbs 2.3%, independent of wavelength. In order to overcome the challenge of limited absorption of a monolayer and better exploit graphene optical properties, a long interaction length is needed. By integrating graphene directly on top of silicon waveguides, longer light/graphene interactions can be achieved. In addition to the linear optical properties of the graphene, its saturable absorption also finds useful applications. Many ultra-short pulse lasers are based on passive mode-locking, where a saturable absorber turns continuous wave output of the laser into a train of optical pulses. And graphene has been shown to make an excellent saturable absorber. However, the saturable absorption behavior of graphene-silicon wavguides and their applications have never been studied. / In this thesis, the linear and saturable absorption of monolayer graphene films transferred onto silicon waveguide are investigated. The transfer process of monolayer graphene to silicon waveguides is studied and linear and saturable absorption measurements are carried out. To investigate applications of graphene-silicon waveguides, a passive mode-lock fiber lasers in which graphene-silicon waveguides act as saturable absorbers to mode-lock pulses is constructed. By adding a tunable filter in cavity, a tunable mode-locked fiber laser based on graphene-silicon waveguide is demonstrated. / Multi-wavelength pulse sources are important for applications including optical fiber communication, instrumentation, and photonic component characterization. The availability of compact, reliable and cost effective multi-wavelength mode-locked lasers is of great importance. We also hope to build multiwavelength mode-locked fiber lasers by integrating CWDM silicon filters with graphene-silicon waveguides. The design process and optimization of a silicon filter called echelle grating is demonstrated. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Shi, Zerui. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references. / Abstracts also in Chinese. / Chapter Chapter 1: --- Introduction --- p.1 / Chapter 1.1 --- Photonic Integrated Circuit (PIC) --- p.1 / Chapter 1.2 --- Silicon on Insulator (SOI) Photonics --- p.3 / Chapter 1.2.1 --- SOI Waveguides --- p.5 / Chapter 1.2.2 --- SOI Waveguide Based Wavelength Division Multiplexing --- p.6 / Chapter 1.3 --- Graphene Photonics --- p.9 / Chapter 1.3.1 --- Band Structure of Monolayer Graphene --- p.9 / Chapter 1.3.2 --- Optical Absorption of Graphene --- p.13 / Chapter 1.3.3 --- Graphene Based Passive Mode-Locked Fiber Lasers --- p.18 / Chapter 1.4 --- Motivation --- p.22 / Chapter 1.5 --- Thesis Outline --- p.23 / Chapter 1.6 --- Reference --- p.24 / Chapter Chapter 2: --- Optical Properties of Graphene-Silicon Waveguides --- p.27 / Chapter 2.1 --- Fabrication and Transfer Process of Graphene-Silicon Waveguides --- p.28 / Chapter 2.1.1 --- Fabrication of SOI Waveguides --- p.28 / Chapter 2.1.2 --- Transfer Process of Monolayer Graphene onto SOI Waveguides --- p.29 / Chapter 2.2 --- Linear Optical Absorption of Graphene-Silicon Waveguides --- p.35 / Chapter 2.2.1 --- Introduction to Photoexcitation in Monolayer Graphene --- p.35 / Chapter 2.2.2 --- Experimental Results of Linear Absorption --- p.37 / Chapter 2.3 --- In-Plane Saturable Absorption of Graphene-Silicon Waveguides --- p.38 / Chapter 2.3.1 --- Experimental Result of In-Plane Saturable Absorption of Graphene-Silicon Waveguides --- p.39 / Chapter 2.3.2 --- Mechanism of Saturable Absorption of Graphene-Silicon Waveguides --- p.42 / Chapter 2.4 --- Summary --- p.44 / Chapter 2.5 --- Reference --- p.45 / Chapter Chapter 3: --- Hybrid Graphene-Silicon Waveguides Based Mode-Locked Fiber Lasers --- p.47 / Chapter 3.1 --- Background of Graphene Based Mode-Locked Fiber Lasers --- p.47 / Chapter 3.1.1 --- Passive Mode-Locked Lasers Fundamentals --- p.47 / Chapter 3.1.2 --- Review of Recent Works of Graphene Based Mode-Locked Fiber Lasers . --- p.52 / Chapter 3.2 --- Hybrid Graphene-Silicon Waveguides Based Mode-Locked Fiber Lasers --- p.55 / Chapter 3.2.1 --- Experimental Set Up and Results --- p.55 / Chapter 3.2.2 --- Discussion --- p.59 / Chapter 3.3 --- Tunable Graphene-Silicon Waveguides Based Mode-Locked Fiber Lasers --- p.62 / Chapter 3.4 --- Summary --- p.66 / Chapter 3.5 --- Reference --- p.66 / Chapter Chapter 4: --- Conclusion and Future Work --- p.68 / Chapter 4.1 --- Conclusion --- p.68 / Chapter 4.2 --- Future Work --- p.69 / Chapter 4.2.1 --- Design and Simulation Results of Echelle Grating --- p.69 / Chapter 4.2.2 --- Optimization and Experiment Results of Echelle Gratings --- p.77 / Chapter 4.2.3 --- Integration of Echelle Grating with SOI Waveguides --- p.82 / Chapter 4.3 --- Summary --- p.84 / Chapter 4.4 --- Reference --- p.85 / Chapter APPENDIX A: --- PUBLICATION LIST --- p.86 / Chapter APPENDIX B: --- LIST OF FIGURES --- p.87 / Chapter APPENDIX C: --- LIST OF TABLES --- p.91 / Chapter APPENDIX D: --- atlab Code of Simulation of Echelle Grating --- p.92

Shi Lei = 溶凝膠分佈反饋波導激光器之光學性質的研究 / 石蕾. / "September 2004." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (p. 150-171) / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese. / Shi Lei = Rong ning jiao fen bu fan kui bo dao ji guang qi zhi guang xue xing zhi de yan jiu / Shi Lei.

Zhang Ailing. / "September 2004." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

An apodized grating coupler with the best coupling efficiency hitherto reported for shallow-etched waveguide grating couplers is described. By appropriate choice of waveguide/grating thicknesses and varying the coupling strength of the grating coupler via tailoring its fill factor to optimize the mode matching, a coupling loss of only 1.2dB was obtained for each fiber/silicon waveguide interface with a slightly titled optical fiber. / Photonic integrated circuits (PICs) based on Silicon-on-insulator (SOI) substrate were proposed to make miniaturized photonic devices on chip, so that low-cost and compact devices for applications including sensing, inter/intra-chip communications and optical fiber communications could be made. One of the key challenges in the development of highly integrated PICs is efficient coupling of light between a submicron-sized nanophotonic wire and an optical fiber due to the large loss inherent from the mismatch in mode field size between the optical fibers and the nanophotonic wire waveguides. An attractive approach for efficient coupling is to use diffractive grating couplers which show many advantages over alternative approaches. However the angled alignment of the optical fiber to the grating as reported in the previous work is not desirable for a low-cost optical packaging process. / The 2D grating couplers could be used as polarization splitter. Polarization insensitive coupling and polarization-diversity circuits are realized by the 2D grating couplers. We also demonstrated a novel silicon waveguide grating which serves dual functions: as a 1x2 variable integrated beam splitter/combiner and as an out-of plane diffractive element for coupling light. The split ratio can be tuned by changing the launch position of the optical fiber without introducing much excess loss. An integrated Mach-Zehnder interferometer (MZI) is implemented with this novel functional element. This MZI was demonstrated as a demodulator for differential phase-shift-keying (DPSK) signal. / We demonstrated a simple technique to realize vertical fiber coupling with linearly chirped grating periods. No additional fabrication process is required yet a comparable coupling efficiency is achieved with the proposed chirped grating couplers with vertical optical fibers. Design and experimental results of onedimensional (lD) gratings, two-dimensional (2D) gratings, focusing gratings and fully-etched nanoholes gratings are described in the thesis. We also describe the waveguides and grating couplers fabricated on silicon-on-sapphire for mid-infrared applications. / Chen, Xia. / Adviser: H.K. Tsang. / Source: Dissertation Abstracts International, Volume: 73-03, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Chan Po Shan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 79). / Text in English; abstracts in English and Chinese. / Chan Po Shan. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Application of Optical Waveguides --- p.1 / Chapter 1.2 --- Planar Waveguide Characterizations --- p.2 / Chapter 1.3 --- Silicon-On-Insulator Rib Waveguides --- p.3 / Chapter 1.4 --- Polarization compensation schemes --- p.4 / Chapter 1.5 --- Objectives --- p.6 / Chapter 2 --- Silicon-On-Insuiator Rib Waveguides --- p.9 / Chapter 2.1 --- Properties of Silicon Waveguides --- p.9 / Chapter 2.2 --- Single Mode Rib Waveguides Simulations --- p.11 / Chapter 2.3 --- Special design optimisations --- p.14 / Chapter 2.4 --- Fabrications and Results --- p.16 / Chapter 3 --- Polarization Characteristics of SOI Rib Waveguides --- p.20 / Chapter 3.1 --- Properties of silicon and effect of rib structure --- p.20 / Chapter 3.2 --- Polarization affected by Form Birefringence --- p.21 / Chapter 3.3 --- Case Study: Arrayed Waveguide Grating --- p.23 / Chapter 3.4 --- Possibility of polarization Compensation in planar waveguides --- p.26 / Chapter 4 --- Fixed Polarization Compensation Techniques --- p.30 / Chapter 4.1 --- Theoretical analysis of slant rib waveguides on polarization --- p.30 / Chapter 4.2 --- Focused Ion Beam Trimming of SOI waveguides --- p.31 / Chapter 4.3 --- Possible applications --- p.36 / Chapter 5 --- Tuneable Polarization Compensation Techniques --- p.41 / Chapter 5.1 --- stress on rib waveguide for polarization compensation --- p.41 / Chapter 5.2 --- Magnetostriction and Magnetostrictive Materials --- p.42 / Chapter 5.3 --- Sputtering of soft magnetic layer on SOI rib waveguides --- p.46 / Chapter 5.4 --- Test results and Analysis --- p.47 / Chapter 6 --- Advanced SOI Devices --- p.55 / Chapter 6.1 --- Unique planar optoelectronics devices --- p.55 / Chapter 6.2 --- Simulation and Fabrications --- p.57 / Chapter 6.3 --- Test Results and Discussion --- p.58 / Chapter 7 --- Conclusion --- p.62 / Chapter 7.1 --- Summary --- p.62 / Chapter 7.2 --- Future work --- p.63 / Appendices / Chapter A1 --- Effective Index Method --- p.66 / Chapter A2 --- Beam Propagation Method --- p.70 / Chapter A3 --- SOI Rib Waveguide Fabrication --- p.72 / Chapter A4 --- Focused Ion Beam --- p.74 / Chapter A5 --- Polarization Optics --- p.76 / List of Publications --- p.79

No description available.

<p>In order to facilitate comprehensibility and translation, the language used in software user documentation must be standardized. If the terminology and language rules are standardized and consistent, the time and cost of translation will be reduced. For this reason, controlled languages have been developed. Controlled languages are subsets of other languages, purposely limited by restricting the terminology and grammar that is allowed.</p><p>The purpose and goal of this thesis is to investigate how using a controlled language can improve comprehensibility and translatability of software user documentation written in English. In order to reach our goal, we have performed a case study at IFS AB. We specify a number of research questions that help satisfy some of the goals of IFS and, when generalized, fulfill the goal of this thesis.</p><p>A major result of our case study is a list of sixteen controlled language rules. Some examples of these rules are control of the maximum allowed number of words in a sentence, and control of when the author is allowed to use past participles. We have based our controlled language rules on existing controlled languages, style guides, research reports, and the opinions of technical writers at IFS.</p><p>When we applied these rules to different user documentation texts at IFS, we managed to increase the readability score for each of the texts. Also, during an assessment test of readability and translatability, the rewritten versions were chosen in 85 % of the cases by experienced technical writers at IFS.</p><p>Another result of our case study is a prototype application that shows that it is possible to develop and use a software checker for helping the authors when writing documentation according to our suggested controlled language rules.</p>

Based on a Sc.D. thesis in the Dept. of Electrical Engineering, 1965. / Bibliography: p.98-99.

R.B. Adler. / "May 27, 1949." / Bibliography: p. 137. / Army Signal Corps Contract No. W36-039-sc-32037 Project No. 102B Dept. of the Army Project No. 3-99-10-022