No description available.

No description available.

Fok Mei-po. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 81-82). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.iv / Table of Content --- p.v / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Overview of Injection Locking --- p.2 / Chapter 1.2 --- Applications of Single Wavelength Injection Locking --- p.4 / Chapter 1.3 --- Applications of Multi-wavelength Injection Locking --- p.5 / Chapter 1.4 --- Organization of Thesis --- p.6 / Chapter 2 --- Principle and Theory --- p.10 / Chapter 2.1 --- Principle of Injection Locking --- p.11 / Chapter 2.2 --- Amplitude Equalization by Injection Locking --- p.14 / Chapter 2.3 --- Repolarization by Injection Locking --- p.16 / Chapter 2.4 --- Reduction of Relative Intensity Noise --- p.18 / Chapter 2.5 --- Multi-wavelength Injection Locking --- p.20 / Chapter 2.6 --- Polarization Maintaining Fiber Loop Mirror Filter --- p.21 / Chapter 2.7 --- Self-phase Modulation --- p.23 / Chapter 3 --- Preliminary Experimental Study --- p.26 / Chapter 3.1 --- Reduction of Amplitude Modulation --- p.27 / Chapter 3.2 --- Repolarization --- p.33 / Chapter 3.3 --- Relative Intensity Noise and Relaxation Oscillation Frequency --- p.35 / Chapter 3.4 --- Spurious Free Dynamic Range --- p.38 / Chapter 4 --- Optical mm-wave Generation --- p.42 / Chapter 4.1 --- Introduction --- p.43 / Chapter 4.2 --- Experimental Details --- p.44 / Chapter 4.3 --- Results and Discussion --- p.46 / Chapter 4.4 --- Summary --- p.52 / Chapter 5 --- Two-mode Injection Locking for Wavelength-tunable Pulse Generation --- p.56 / Chapter 5.1 --- Introduction --- p.57 / Chapter 5.2 --- Experimental Details --- p.58 / Chapter 5.3 --- Results and Discussion --- p.60 / Chapter 5.4 --- Summary --- p.64 / Chapter 6 --- Multi-wavelength Injection Locking Using a Polarization Maintaining Fiber Loop Mirror Filter --- p.67 / Chapter 6.1 --- Introduction --- p.69 / Chapter 6.2 --- Preliminary Study of the Generation of Multi-wavelength Injection Source --- p.70 / Chapter 6.3 --- Experimental Details --- p.73 / Chapter 6.4 --- Results and Discussion --- p.75 / Chapter 6.5 --- Summary --- p.80 / Chapter 7 --- Conclusion and Future Work --- p.83 / Chapter 7.1 --- Conclusion --- p.84 / Chapter 7.2 --- Future Work --- p.87 / Appendices --- p.A-i / Appendix A. List of Publication --- p.A-i / Appendix B. List of Figures --- p.A-iii

No description available.

Le domaine des sciences et technologies Térahertz gagne un intérêt international en raison de ses nombreuses applications allant des systèmes de transmission sans fils ultra rapide au diagnostique médical, au contrôle de qualité et à la sécurité industrielle. Aujourd’hui, cet intérêt pousse la recherche en électronique à se focaliser sur la réduction des composants dans le but d’augmenter leur fréquence de fonctionnement. Les nanotechnologies sont donc au cœur de cette course à la montée en fréquence. La gamme des longueurs d'onde THz ouvre une nouvelle ère de systèmes directement liés à l'information et aux technologies de communication, étendant considérablement ceux déjà existant qui reposent sur des dispositifs optiques et électroniques. Les dispositifs THz à base de semi-conducteurs sont une des voies possibles pour la réalisation de composants à l’interface entre les micro-ondes et la phonique. L'application à grande échelle du domaine des THz pour l'astronomie, l'environnement, les communications, l'imagerie, la sécurité, la biologie et la médecine pourraient conduire à définir la gamme THz comme un champ d’application spécifique pour les chercheurs et les ingénieurs. Par exemple la spectroscopie moléculaire très importante pour l'astronomie (analyse des gaz interstellaires, observations planétaires), l'environnement (surveillance de la pollution), les télécommunications, les communications locales sécurisées (à travers une forte atténuation en dehors de la zone ciblée) à très haut débit de données sera à terme possible. L'imagerie également un élément important contribuant à la sécurité (détection d’armes et de matériel illicite, analyse non destructive et non invasive d’objets).L'un des obstacles pour le développement d’applications pratique dans la gamme du THz est le manque de sources continues, compactes, accordables et puissantes (à faible coût, si possible). Ainsi, ce travail s’inscrit dans le cadre du projet européen ROOTHz et nous proposons d'exploiter les oscillations type Gunn sur un nouveau type de nanodispositifs fabriqués pour la première fois sur du nitrure de Gallium : La diode autocommutante, ou Self switching diode (SSD). Sur la base de simulations Monte-Carlo, la géométrie particulière des SSD favorise l'apparition d'oscillations Gunn à des fréquences Térahertz, en utilisant une dyssymétrie d'un canal de type transistor assez étroit, la SSD peut fournir un comportement de redressement. Cet effet, basé sur les effets de surface et les effets électrostatiques, utilisé sur le GaN permet le fonctionnement comme détecteurs THz à température ambiante. Au cours de cette thèse, des études sur les SSD à base de nitrure de gallium ont été menées afin d'évaluer leurs potentialités comme émetteurs et détecteurs dans la gamme de fréquence du THz. / The field of Terahertz Science and Technology is gaining international interest due to its numerous applications ranging from ultra high speed optical transmission systems to medical diagnosys, industrial quality control and security-screening tools. In this field, the efforts of electronics industry are centered on device scaling down to the nanometer range to increase the operational speed.The THz range is an intermediate range of wavelengths that will open a new area of systems directly related to information and communication technologies, significantly extending the present ones based on photonic and electronic devices. Thus, solid-state THz devices can be either considered as belonging to both fields or to none of them. Indeed the wide application area of THz for astronomy, environment, communications, imaging, security, biology and medicine could lead to define the THz range as a specific scientific, engineering and application field. Molecular spectroscopy is very important for astronomy (analysis of the interstellar gas, planetary observations), environment (pollution monitoring), etc. For telecommunications, secure local communications (through high attenuation outside the targeted area) with ultrahigh data rates will be possible. Imaging is an important application for security (weapon and illicit material detection), biology and medicine. The emergence of novel functional THz devices will be of immense interest for all those applications. One of the bottlenecks for the practical development of THz applications is the fabrication of room temperature (RT), continuous wave, compact, tunable and powerful sources (at low cost, if possible). For this sake, in the framework of the EU funded project ROOTHz, we propose to exploit THz Gunn oscillations in novel wide bandgap semiconductor nanodevices, which have been predicted by simulations but not experimentally confirmed yet, the Self Switching Diode (SSD). By breaking the symmetry of a narrow channel, SSD can provide a rectifying behaviour (based on surface and electrostatic effects) and using high-mobility material systems their operation frequency as detectors can approach the THz range at RT. Interestingly, the special geometry of SSDs also benefits the onset of Gunn oscillations.During this thesis, studies on Gallium nitride SSDs have been performed in order to evaluate their potentialities as emitters and detectors in the THz frequency range.

Nichia Corporation announced blue Light Emitting Diodes (LED) by 1993. They were widely used in markets by 1996 after combining blue LED with yellow phosphors to emit white lights. There¡¦re two keys to utilize LED as replacement light energy; one is to increase the chipset brightness, while another is to use LED arrays instead of single LED. Around 15 to 20% of LED illuminant will be transformed to visible light, while up to 85% of the LED illuminant will be transformed to heat. Therefore, before there¡¦s obvious breakthrough on LED constructions to heat, thermal management of LED is relatively important. The purpose of this research is to do value simulation by slightly change the construction of low power LED and increase its power (150, 350mA), to investigate the differences of high power LED in thermal transmission by single LED and LED arrays under different parameters, and learn if the emitted heat can be tolerated by its key materials. This research can be used as the reference to design LED products for engineers. According to the analysis result, under environment temperature of 25 to 80 Celsius Degree, the temperatures of a 0.5W LED chipset, mounted board and packing materials will increase around 3 to 4 Celsius Degrees when the environment temperature will increase one Celsius Degree. If we increase the LED chipset power to be 1W, the temperature increase for chipset and mounted board is around 3 to 4 Celsius Degrees while the temperature increase for packing materials is 3 to 9 Celsius Degrees. Regarding high power LED arrays, according to the analysis result, when the distance between two LEDs is too small, the temperature will increase dramatically; when the P value (see report content) is over 5mm, per 1mm distance increase, the chipset temperature decrease will become 1 to 2.5 Celsius Degrees from initially 3 to 5 Celsius Degrees. If we further increase the two LEDs distance, there¡¦ll be no significant effect from chipset itself but only the mounted board.

Thesis (M.S. in electrical engineering)--Washington State University, December 2009. / Title from PDF title page (viewed on Dec. 28, 2009). "School of Electrical Engineering and Computer Science." Includes bibliographical references (p. 49-51).

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references (leaves 78-84). Available also in a digital version.

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

Thesis (Ph. D.)--Lehigh University, 2003. / Includes vita. Includes bibliographical references (leaves 162-172).