Abstract This thesis studies the level of performance achievable using today's standard IC processes in the integrated RF subcircuits of the modern GSM base station. The thesis concentrates on those circuit functions, i.e. I/Q modulators, variable gain amplifiers and frequency synthesizers, most relevant for integration in the base station environment as pinpointed by studying the receiver/transmitter architectures available today. Several RF integrated circuits have been designed, fabricated and their level of performance measured. All main circuits were fabricated in a standard double-metal double-poly 1.2 and 0.8 μm BiCMOS process. Key circuit structures and their measured properties are: 90° phase shifter with ±1° phase error with VCC = 4.5…5.5 V and T = -10…+85 °C, I/Q modulator suitable for operation at output frequencies from 100 MHz to 1 GHz and baseband frequencies from 60 to 500 kHz (2.0 mm × 2.0 mm, 100 mA, 5.0 V) with LO suppression of 38 dBc and image rejection of 41 dBc, temperature compensated DC to 1.5 GHz variable gain amplifier (1.15 mm × 2.00 mm, 100 mA, 5.0 V) with a linear 50 dB gain adjustment range, maximum gain of 18.5 dB and gain variation of 1 dB up to 700 MHz over the whole operating conditions range of VCC = 4.5…5.5 V and T = -10…+85 °C, a complete bipolar semicustom synthesizer (90…122 mA, 5.0 V) and two complete full-custom BiCMOS synthesizer chips including all building blocks of a PLL-based synthesizer except for the voltage controlled oscillator and the loop filter. The synthesizers include circuit structures such as ∼2 GHz multi-modulus divider and low-noise programmable phase detector/charge pump (18.7 pA/√Hz at Iout = 500 μA) and have an exemplar phase noise performance of -110 dBc/Hz at 200 kHz offset. One of the main problems of the integer-N PLL based synthesizer when used in a multichannel telecommunications system is the level of spurious signals at the output, when the synthesizer is optimised for fast frequency switching. Therefore, a method using only two current pulses to make the frequency step response of the loop faster, thus allowing a narrower loop bandwidth to be used for additional spur suppression, is proposed. The operation of the proposed speed-up method is analysed mathematically and verified by measurements of an existing RF-IC synthesizer operating at 800 MHz. Measurements show that simple current pulses can be used to speed up the channel switching of a practical RF synthesizer having a frequency step time in the tens of μs range. In the example, a 7.65 MHz frequency step was made seven times faster using the proposed method.

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[pt] Neste trabalho são estudados os moduladores delta desenvolvido a partir do conhecimento estatístico disponível sobre o sinal a ser transmitido. Estes moduladores são aqui chamados estruturados. Após uma rápida introdução à modulação delta, são descritos alguns sistemas mais conhecidos. Os sistemas estruturados são então formalmente caracterizados e uma análise teórica é desenvolvida, sendo apontadas as dificuldades analíticas envolvidas. A partir de uma configuração básica proposta por C.L. Song, são desenvolvidas equações gerais diferentes das por ele obtidas. A particularização destas equações para sinais Gauss Markov de primeira Ordem dá origem ao chamado sistema Song modificado. Resultados obtidos a partir da simulação digital do sistema de song, do sistema de Song modificado, e do sistema delta simples, são apresentados. Um processo adaptativo para aumentar a faixa dinâmica é proposto com base nos resultados de simulação. / [en] This work examines delta modulation systems in which statistical knowledge about the signal to be tranmitted is explicitly used in sistem design. These modulators are called here structured delta modulators. After a brief introduction to delta modulation some well-known systems are described. Structured systems are then formally defined and analytical difficulties in finding general solutions are pointed out. Starting from a system proposed by C.L. Song, general equations are derived. These equations, which are more complete than the ones obtained by Song are then specialized to first-order Gauss-Maarkov signals, leading to what has been called a modified Song modulators. Digital simulations results are then obtained for song modulators, modified Song modulators and linear delta modulators. An adptive producedure is finally suggested to improve the dynamic range of these systems.

Chapter 1: The unique chemical and biological properties of porphyrins have led to increased interest in the development of porphyrin-based materials. Metal organic frameworks (MOFs) can act as a scaffold for the immobilization of porphyrins in desired arrangements. The crystalline nature of MOFs allows for control over spatial arrangement of porphyrins and the local environment of the porphyrin molecules. This opens up the possibility of conducting systematic studies aimed at exploring structure-property relationships. Several strategies for the design and synthesis of porphyrin-based frameworks have been developed over the last two decades, such as, the pillared-layer strategy, construction of nanoscopic metal-organic polyhedrals (MOPs), post-synthetic modification, etc. These strategies provide an opportunity to engineer porphyrin-based MOFs that can target a specific application or serve as multi-functional assemblies. Porphyrin-based MOFs provide a tunable platform to perform a wide variety of functions ranging from gas adsorption, catalysis and light harvesting. The versatile nature of these frameworks can be exploited by incorporating them in multi-functional assemblies that mimic biological and enzymatic systems. Nano-thin film fabrication of porphyrin-based MOFs broadens their application range, making it possible to use them in the construction of photovoltaic and electronic devices. Chapter 2: The reaction of zirconium salts with meso-tetracarboxyphenylporphyrin (TCPP) in the presence of different modulators results in the formation of a diverse set of metal-organic frameworks (MOFs), each displaying distinct crystalline topologies. However, synthesis of phase-pure crystalline frameworks is challenging due to the concurrent formation of polymorphs. The acidity and concentration of modulator greatly influence the outcome of the MOF synthesis. By systematically varying these two parameters, selective framework formation can be achieved. In the present study, we aimed to elucidate the effect of modulator on the synthesis of zirconium-based TCPP MOFs. With the help of powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM), modulator candidates and the optimal synthetic conditions yielding phase-pure PCN-222, PCN-223 and MOF-525 were identified. 1H NMR analysis, TGA and N2 gas adsorption measurements were performed on select MOFs to gain insight into the relationship between their defectivity and modulator properties. Chapter 3: Singlet-singlet energy transfer in PCN-223(free-base), a highly stable Zr-MOF based on meso-tetrakis(4-carboxyphenyl)porphyrin was investigated, using diffuse reflectance spectroscopy, steady-state emission spectroscopy, time-correlated single photon counting (TCSPC) spectroscopy and nanosecond transient absorption spectroscopy. The effects of the surrounding media and temperature on the excited-state properties of PCN-223(fb) were explored to understand the mechanistic aspects of energy transfer. Stern-Volmer photoluminescence quenching of PCN-223(fb) suspensions was performed to extract quenching rate constants and gain insight into the efficiency of energy transfer. Chapter 4: The fourth chapter of this thesis is adapted from chapter 14 of the book "Elaboration and Applications of Metal-Organic Frameworks" authored by Jie Zhu, Shaunak Shaikh, Nicholas J Mayhall and Amanda J Morris. This chapter summarizes the fundamental principles of energy transfer in MOFs and provides an overview of energy transfer in lanthanide-Based luminescent MOFs, Ru/Os-Based MOFs, porphyrin- and metalloporphyrin-based MOF materials, and nonporphyrinic, organic chromophore-based MOFs. / Master of Science / Metal Organic frameworks (MOFs) composed of Zirconium-oxo clusters connected through meso-tetra(4-carboxyphenyl)porphyrin (TCPP) linker molecules have emerged as promising solid-state materials because of their unique structural features and diverse applications. Although these MOFs have demonstrated great potential over the years, synthesizing them in phase-pure form has proven to be very challenging as they are susceptible to polymorphism. Syntheses of these frameworks often result in phase mixtures and have poor reproducibility. To address, this issue, we conducted a systematic exploration of the synthetic parameter landscape to identify reaction conditions for the synthesis of phase-pure Zirconium-based porphyrin MOFs, and to gain deeper insights into the factors governing the formation of these MOFs. We also investigated the defectivity of pristine Zr-TCPP MOFs using a variety of techniques, including 1H NMR spectroscopy, thermogravimetric analysis (TGA), inductively coupled plasma mass spectrometry (ICP-MS), and Nitrogen gas adsorption/desorption measurements. The long-term goal of this project is to use phase-pure Zr-based porphyrin MOFs as model systems to study energy transfer in three dimensional structures. To achieve this goal, we characterized the photophysical properties of PCN-223(fb) (a Zr-based porphyrin MOF) using a variety of techniques including steady-state photoluminescence spectroscopy, time-resolved photoluminescence spectroscopy, nanosecond transient absorption spectroscopy and femtosecond transient absorption spectroscopy. Understanding the mechanistic aspects of energy transfer in PCN-223(fb) can pave the way for the design of a new generation of solar energy conversion devices.

Film display holograms typically diffract light over a wide enough view-angle to be viewed, directly, without intervening optics. However, all holographic video displays must use optics beyond the hologram surface to overcome the challenges of small display extent and low diffraction angle by using some form of demagnification and derotation. We report a leaky mode waveguide spatial light modulator (SLM) with sufficiently high angular diffraction to obviate the need for demagnification in scanned aperture systems. This was achieved by performing a number of experiments to determine the depth of the annealed, proton-exchanged waveguide which corresponded to a maximized diffracted angle. Diffraction sweeps were recorded in excess of 19.5° for 632.8 nm light which is above the 15° required for direct view display. Moreover, we present a paired set of waveguide SLMs capable of a maximum light deflection nearing 28° for red. This deflection, which is several times larger than the angular sweep of current, state-of-the-art modulators, is made possible by the unilateral, near-collinear waveguide nature of the leaky mode interaction. The ability to double angular output in this way, which is either not possible or not practical in other SLMs, is possible in leaky mode devices, thanks to the absence of zero-order light and the lack of high-order outputs. This combined structure has angular deflection high enough to enable color holographic video monitors that do not require angular magnification. Furthermore, the low cost and high angular deflection of these devices may make it possible to make large arrays for flat-screen video holography. One improvement that could be made to the current setup would be to increase the device's diffraction efficiency. One highly influential factor of diffraction efficiency for a Bragg-regime surface acoustic wave (SAW) grating is the length of the interaction between the light and the grating. In this work, we have shown that guided light in a reverse proton exchanged (RPE) waveguide experiences less loss. This enables us to create longer devices which eventually results in devices with higher diffraction efficiency. We have also researched on LCoS SLMs and used them for two different applications: (a) photophoretic-trap volumetric displays and (b) holographic video displays. In the first case, aberrations including spherical, astigmatism, and coma can make particles to trap tighter in the focal point of the beam. Also, a new approach for holographic computations is presented which uses the electromagnetic nature of light in Maxwell Equations to find a unique phase map for every specific 3D object in space.

Film display holograms typically diffract light over a wide enough view-angle to be viewed, directly, without intervening optics. However, all holographic video displays must use optics beyond the hologram surface to overcome the challenges of small display extent and low diffraction angle by using some form of demagnification and derotation. We report a leaky mode waveg- uide spatial light modulator (SLM) with sufficiently high angular diffraction to obviate the need for demagnification in scanned aperture systems. This was achieved by performing a number of experiments to determine the depth of the annealed, proton-exchanged waveguide which corresponded to a maximized diffracted angle. Diffraction sweeps were recorded in excess of 19.5<°> for 632.8 nm light which is above the 15<°> required for direct view display.Moreover, we present a paired set of waveguide SLMs capable of a maximum light deflection nearing 28<°> for red. This deflection, which is several times larger than the angular sweep of current, state-of-the-art modulators, is made possible by the unilateral, near-collinear waveguide nature of the leaky mode interaction. The ability to double angular output in this way, which is either not possible or not practical in other SLMs, is possible in leaky mode devices, thanks to the absence of zero-order light and the lack of high-order outputs. This combined structure has angu- lar deflection high enough to enable color holographic video monitors that do not require angular magnification. Furthermore, the low cost and high angular deflection of these devices may make it possible to make large arrays for flat-screen video holography.One improvement that could be made to the current setup would be to increase the device<&trade>s diffraction efficiency. One highly influential factor of diffraction efficiency for a Bragg-regime surface acoustic wave (SAW) grating is the length of the interaction between the light and the grating. In this work, we have shown that guided light in a reverse proton exchanged (RPE) waveguide experiences less loss. This enables us to create longer devices which eventually results in devices with higher diffraction efficiency.We have also researched on LCoS SLMs and used them for two different applications: (a) photophoretic-trap volumetric displays and (b) holographic video displays. In the first case, aberrations including spherical, astigmatism, and coma can make particles to trap tighter in the focal point of the beam. Also, a new approach for holographic computations is presented which uses the electromagnetic nature of light in Maxwell Equations to find a unique phase map for every specific 3D object in space.

Photonic links have been proposed to transport radio frequency (RF) signals over optical fiber. External optical modulation is commonly used in high performance RF-photonic links. The practical use of optical fiber to transport RF signals is still limited due to high RF signal loss. In order to reduce the RF signal loss, highly efficient modulators are needed. For many applications, modulators with broad bandwidths are required. However, there are applications that require only a narrow bandwidth. For these narrow-band applications, the modulation efficiency can be improved through the resonant enhancement technique at the expense of reduced bandwidth. The aim of this thesis is to investigate highly efficient Mach-Zehnder optical modulators (MZMs) on Lithium Niobate (LiNbO3) with resonant enhancement techniques for narrow-band RF-photonic applications. This work focuses in particular on analyzing the factors that affect the modulation efficiency through resonant enhancement so that the modulator electrode structure can be optimized for maximum modulation efficiency. A parameter study of the effects of the electrode characteristics on the modulation efficiency of resonantly enhanced modulators (RE-MZM) is provided. From this study, optimum design objectives are identified. Numerical optimization is employed to explore the design trade-offs so that optimal configurations can be found. A sensitivity analysis is carried out to assess the performance of optimal RE-MZMs with respect to the variations of fabrication conditions. The results of these investigations indicate that the RE-MZM with a large electrode gap is the optimal design since it provides high modulation efficiency although the inherent switching voltage is high, and is the most tolerant to the fabrication fluctuations. A highly efficient RE-MZM on X-cut LiNbO3 is practically demonstrated with the resonant enhancement factor of 5 dB when comparing to the unenhanced modulator with the same electrode structure and effective switching voltage of 2 V at 1.8 GHz. The performance of the RF-photonic link using the fabr icated RE-MZM is evaluated. Optimization of RE-MZMs for operating at millimeter-wave frequencies is also reported. Factors that limit the modulation efficiency of an RE-MZM at millimeter-wave frequencies are identified. Novel resonant structures that can overcome these limitations are proposed. Preliminary designs indicate that greatly improved modulation efficiency could be expected.

Integration of complex optical functionalities with high performance will lead to a huge development in the field of nanophotonics for a broad range of applications. Silicon photonics is currently the leading technology for the implementation of low-cost photonic integrated devices. The great potential of this technology relies on its compatibility with the mature silicon integrated circuits manufacturing based on complementary metal-oxide semiconductor (CMOS) processes widely used in microelectronic industry and the availability of high quality silicon-on-insulator wafers, an ideal platform for creating planar waveguide circuits that offers strong optical confinement due to the high index contrast between silicon (n=3.45) and silicon dioxide (n=1.45). In order to keep improving the performance of photonic devices on silicon, the integration of CMOS compatible materials with unique properties shows up as an excellent opportunity to overcome the current limitations in silicon while offering unprecedented and novel capabilities to the silicon platform. In this way, barium titantate (BaTiO3) stands out as one of the most disruptive candidates. The work developed in this thesis is essentially focused on the design, fabrication and characterization of an electro-optic modulator based on a hybrid BaTiO3 on silicon structure for the implementation of high performance electro-optic functionalities with beyond state-of-the art performance that currently cannot be afforded in silicon photonics technology. / La integración de funcionalidades ópticas con alto rendimiento llevará a un gran desarrollo en el campo de la nanofotónica para un amplio abanico de aplicaciones. Actualmente, la fotónica de silicio es la tecnología líder para la implementación de dispositivos fotónicos integrados a bajo coste. El gran potencial de esta tecnología reside en su compatibilidad con las maduras técnicas de fabricación de circuitos integrados de silicio basadas en los procesos "complementary metal-oxide semiconductor" (CMOS) ampliamente utilizados en la industria microelectrónica y la disponibilidad de disponer de obleas de silicio sobre aislante de alta calidad, una plataforma ideal para crear circuitos de guía de ondas planas que ofrecen un fuerte confinamiento óptico debido al alto contraste índices entre el silicio (n=3,45) y el dióxido de silicio (n=1,45). Para poder mejorar el rendimiento de dispositivos fotónicos en silicio, la integración de materiales con propiedades excepcionales y compatibles con los procesos de fabricación CMOS surge como una excelente oportunidad para superar las actuales limitaciones de la tecnología de silicio al mismo tiempo que ofrece oportunidades novedosas y sin precedentes en la plataforma de silicio. En este sentido, el material titanato de bario (BaTiO3) se postula como uno de los candidatos más prometedores. El trabajo desarrollado en esta tesis está esencialmente enfocado en el diseño, fabricación y caracterización de un modulador electro-óptico basado en una estructura híbrida de BaTiO3 en silicio para la implementación de funcionalidades electro-ópticas de alto rendimiento más allá del estado del arte de las que no se puede disponer actualmente en la tecnología de fotónica de silicio. / La integració de funcionalitats òptiques amb alt rendiment portarà a un gran desenvolupament en el camp de la nanofotònica per a un ampli ventall d'aplicacions. Actualment, la fotònica de silici és la tecnologia capdavantera per a la implementació de dispositius fotònics integrats a baix cost. El gran potencial d'aquesta tecnologia resideix en la seva compatibilitat amb les madures tècniques de fabricació de circuits integrats de silici basades en els processos "complementary metal-oxide semiconductor" (CMOS) amplament utilitzats en la indústria microelectrònica i la disponibilitat de disposar d'hòsties de silici sobre aïllant d'alta qualitat, una plataforma ideal per crear circuits de guia d'ones planes que ofereixen un fort confinament òptic a causa de l'alt contrast d'índexs entre el silici (n=3,45) i el diòxid de silici (n=1,45). Per poder millorar el rendiment de dispositius fotònics en silici, la integració de materials amb propietats excepcionals i compatibles amb els processos de fabricació CMOS sorgeix com una excel·lent oportunitat per superar les actuals limitacions de la tecnologia de silici al mateix temps que ofereix oportunitats noves i sense precedents en la plataforma de silici. En aquest sentit, el material titanat de bari (BaTiO3) es postula com un dels candidats més prometedors. El treball desenvolupat en aquesta tesi està essencialment enfocat en el disseny, fabricació i caracterització d'un modulador electro-òptic basat en una estructura híbrida de BaTiO3 en silici per a la implementació de funcionalitats electro-òptiques d'alt rendiment més enllà de l'estat de l'art de les quals no es pot disposar actualment a la tecnologia de fotònica de silici. / Castera Molada, P. (2017). Development of new photonic devices based on barium titanate in silicon [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/86197 / TESIS

Wong Chi Ming. / "August 2004." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (p. 182-215). / 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.