A BCB Polymer/Ta2O5/SiO2 antiresonant reflecting optical waveguide (ARROW) at quasi-antiresonant condition is presented. The waveguide consists of the SiO2 second cladding, the Ta2O5 first cladding, and the BCB core. The lateral guiding of the ARROW waveguide was formed by reactive ion etching based on SF6 and O2 mixtures (SF6 : O2 =1.5 : 1). A metal layer Ni/Cr thin films were used as the etch mask to avoid cracking of the mask caused by large thermal expansion coefficient of the BCB Polymer. The waveguide losses were measured by the cut back method. Large dry-etching aspect ratio of the BCB polymer to the etch mask was obtained. For TE polarized light, the propagation loss of the waveguide was 1.12 dB/cm at 1.3£gm. The propagation loss for TM polarized light was 2.56 dB/cm.

A novel variable optical attenuator based on buried polymer waveguides and waveguide bends is proposed. The attenuator consists of three waveguide sections, separated for waveguide bending by two embedded micorprisms. The attenuation of device was achieved by steering the beam propagation direction in the waveguide by thermo-optical effects. Detailed simulation results using the Beam Propagation Method are presented. In addition, radiation losses of the waveguide bends are experimentally investigated. After two-10¢X bends, the normalized insertion losses as low as 65.7¢H are obtained. The propagation loss of the buried waveguide is 0.47dB/cm at l=1.3 mm.

Abstract Ridge-type 1.3£gm InGaAsP diode lasers with planar waveguide structure have beem successfully fabricated and mounted on silicon submounds. The laser diodes were fabricated by first etch a ridge structure for light guidance.Typical ridge width is around 3£gm. After ridge etching, a SiO2 thin film was sputtered onto the sample as surface passivation layer, fllowing by the coating of Benzocyclobutene (BCB) polymer for surface planarization.The unwanted BCB polymer was removed by dry etching process until the passivation oxide can be observed.Before metallization, SiO2 layers above the ridge were removed by wet etching technique. The fabrication was completed by evaporating contact metals to the samples. The finished samples were cleaved into laser dies with a dimension of 500£gm¡Ñ300£gm.The dies were mounted onto a Si submound for DC and AC measurement.The threshold current of the planarized laser is 34mA.The threshold voltage and total resistance of the planar device are 1.31V and 10.1£[.The quantum efficiency as large as 76¢H is obtained.The frequency response of the device is also measured.The 3dB bandwidth is about 1.9GHz¡C

O objetivo da presente dissertação é avaliar a atuação do Banco Central do Brasil no controle do excesso de volatilidade da taxa de câmbio. Para tanto, estima-se um modelo SETAR com dois limiares, com o intuito de identificar uma estrutura não linear na taxa de câmbio e, por meio da proposição de um modelo teórico, avaliar de que forma ocorreria a tomada de decisão acerca de intervenções no mercado de câmbio. Busca-se, também, por meio de simulações do modelo teórico proposto, entender como se relacionariam o comportamento de maior prazo da taxa de câmbio e a política de controle da volatilidade. Conclui-se que períodos marcados por uma tendência de constante depreciação (apreciação) da moeda podem estar relacionados a momentos de redução (acúmulo) de reservas internacionais mantidas pelo Banco Central. / The objective of this dissertation is to evaluate the behavior of the Brazilian Central Bank, in its role of to controling exchange rate excess volatility. A SETAR model with two thresholds is estimated in order to identify a nonlinear structure for the exchange rate. A theoretical model is proposed for the monetary authority in order to evaluated optimal intervention policy. The theoretical model is then simulated to show how long-run trends in the exchange rate could be smoothed by control policies. The results shows that depreciation (appreciation) trends could be related to significant reductions (accumulation) of international reserves.

Les travaux présentés dans cette thèse sont une contribution à l'étude d'antennes reconfigurables à base de MEMS en intégration hétérogène 3D pour les systèmes de communication millimétriques. Ces travaux de thèse s'inscrivent dans le cadre d'un projet ANR nommé SIPCOM (Intégration hétérogène 3D (System-In-Package) pour objets communicants en gamme millimétrique), qui concerne l'intégration hétérogène d'un microsystème intelligent communicant à 60GHz. Au cours de ce manuscrit, nous proposons la réalisation d'antennes sur membrane selon 3 technologies. Dans un premier temps, une nouvelle technologie simple et bas coût basée sur un empilement de FR4 et de Pyralux ainsi qu'un nouveau concept d'antenne patch sur membrane alimentée par un guide d'onde intégré via une fente de couplage sont présentés. Dans un second temps, ce nouveau concept d'antenne a été adapté afin de pouvoir l'intégrer au module SiP réalisé en technologie Silicium / BCB. Enfin, la troisième technologie basée sur des substrats de quartz permet de démontrer la faisabilité d'une antenne à balayage électronique pour laquelle chaque excitateur est intégré dans le design d'un déphaseur à base de MEMS permettant de s'affranchir des interconnexions par bonding entre le déphaseur et la partie antennaire. / The work presented in this PhD thesis is a contribution for the study of reconfigurable antennas based on MEMS integration for 3D heterogeneous millimeter communication systems. This study falls within the framework of a ANR project named SIPCOM, for heterogeneous integration of smart millimeter communicating systems. During this manuscript, we propose the implementation of membrane antennas with three technological processes. Firstly, a new simple and low cost technology based on FR4 and Pyralux substrates and a new concept of patch antenna fed by integrated waveguide are investigated. In a second time, this new antenna design has been matched in order to be integrated in the SIP module using Silicon/BCB technology. The third technology based on quartz substrates is used to demonstrate the feasibility of an electronic beamscanning antenna for which one each slot feeder is integrated into the design of the MEMS phase shifter to overcome the bonding interconnections between the phase shifter and the antenna.

O objetivo da presente dissertação é avaliar a atuação do Banco Central do Brasil no controle do excesso de volatilidade da taxa de câmbio. Para tanto, estima-se um modelo SETAR com dois limiares, com o intuito de identificar uma estrutura não linear na taxa de câmbio e, por meio da proposição de um modelo teórico, avaliar de que forma ocorreria a tomada de decisão acerca de intervenções no mercado de câmbio. Busca-se, também, por meio de simulações do modelo teórico proposto, entender como se relacionariam o comportamento de maior prazo da taxa de câmbio e a política de controle da volatilidade. Conclui-se que períodos marcados por uma tendência de constante depreciação (apreciação) da moeda podem estar relacionados a momentos de redução (acúmulo) de reservas internacionais mantidas pelo Banco Central. / The objective of this dissertation is to evaluate the behavior of the Brazilian Central Bank, in its role of to controling exchange rate excess volatility. A SETAR model with two thresholds is estimated in order to identify a nonlinear structure for the exchange rate. A theoretical model is proposed for the monetary authority in order to evaluated optimal intervention policy. The theoretical model is then simulated to show how long-run trends in the exchange rate could be smoothed by control policies. The results shows that depreciation (appreciation) trends could be related to significant reductions (accumulation) of international reserves.

Made available in DSpace on 2014-08-20T13:32:49Z (GMT). No. of bitstreams: 1 tese_elisa_caroline_da_silva_santos.pdf: 986483 bytes, checksum: 66da36a6826c54f5bd79701d8e49d914 (MD5) Previous issue date: 2014-02-18 / The production of swine embryos in vitro requires efficient in vitro maturation (IVM), which can be achieved by selection the most competent cumulus-oocyte complexes COC).The Brilliant Cresyl Blue (BCB) dye allows the selection of COC with complete growth by assessing their levels of the G6PDH enzyme. However, there is a possible negative effect of selection with BCB. This effect may be due to its intrinsic toxicity or to factors related to the composition of the media used during the test. This research had the objectives: to determine potential toxicity after exposure to BCB and to evaluate the effect of different medias for BCB staining on the ability to support oocyte development. On the first research, after BCB staining and after IVM, several tests were performed to evaluate the effects of their potential toxicity on mitochondrial activity and functionality: reactive oxygen species (ROS), ATP, mitochondrial membrane potential and the number of copies of mitochondrial DNA. The results showed that oocytes stained with BCB produced high levels of ROS, compared with control immediately after staining and after the IVM. The ATP and mitochondrial membrane potential showed similar results between groups after staining, however, after IVM oocytes BCB showed lower membrane potential and ATP. There was no difference in the number of copies of mtDNA in the evaluated groups. Already, on test of ATP content in early embryos, ATP was lower in BCB oocytes, however, there was no difference statistical. In second study, the most commonly used media, D-PBS, was compared with a more elaborate media for BCB called here: ReproPEL. The COC s submitted to both media were submitted to nuclear and cytoplasmatic maturation, parthenogenetic activation, and to the comet test. The great rates of nuclear IVM (P<0.05) were obtained for DPBS+ (63.1%), ReproPELc (55.1%) and ReproPEL+ (50.2%). The group with smaller area of CG (P<0.05), showing better migration, were ReproPELc, D-PBS+, D-PBS- and ReproPEL+. The parthenogenetic activation indicated that ReproPEL media presented satisfactory capacity of oocyte maintenance, resulting in acceptable rates of development to blastocyst stage: 13.0% for ReproPEL+; and 12.7% for ReproPELc. So, the ReproPEL media can be used for maintenance of swine oocytes, but it was not the most appropriate media for BCB staining. Moreover, after exposure to BCB and after IVM, BCB oocytes presented high toxicity at mitochondrial level, due to increased production of ROS, decreased membrane potential and compromised ATP production. However, the mitochondrial function was restored in early embryonic development. In conclusion, BCB was responsible for toxicity in immature swine oocytes, nevertheless, further studies must be performed to evaluate the changes caused by BCB in the embryonic level. / Para a obtenção de embriões suínos produzidos in vitro faz-se necessário que a maturação in vitro (MIV) ocorra de forma eficiente, o que exige a seleção dos complexos cumulus-oócitos (CCOs) mais competentes. O corante Brilliant Cresyl Blue (BCB) permite selecionar os CCOs que completaram seu crescimento, mediante a avaliação dos níveis da enzima G6PDH. Entretanto, existe um possível efeito nocivo relacionado ao processo de seleção com BCB, o qual pode ser devido a uma toxicidade intrínseca do corante ou aos vários fatores relacionados à composição dos meios para a realização do teste. Desta forma, esta pesquisa teve como objetivos: averiguar a existência de toxicidade após exposição ao BCB e avaliar o efeito de diferentes meios para a coloração com BCB sobre a capacidade de suporte ao desenvolvimento oocitário. Na primeira pesquisa, após a coloração com BCB e após a MIV, vários testes foram realizados para avaliar os efeitos de sua potencial toxicidade sobre a atividade e a funcionalidade mitocondrial: análises de espécies reativas de oxigênio (ROS), ATP, potencial de membrana mitocondrial e número de cópias de DNA mitocondrial. Como resultados, obteve-se que oócitos corados com BCB produziram altos níveis de ROS quando comparados com o controle imediatamente após a coloração e após a MIV. O ATP e potencial de membrana mitocondrial apresentaram resultado similar entre os grupos após a coloração, porém, após a MIV oócitos BCB apresentaram menor potencial de membrana e ATP. Não ocorreu diferença no número de cópias do DNAmt nos grupos avaliados. Já, no teste do conteúdo de ATP em embriões iniciais, o ATP foi inferior em oócitos BCB, porém, não ocorreu diferença significativa. Na segunda pesquisa, comparou-se o meio mais utilizado, D-PBS, com um meio mais elaborado para o BCB, chamado de ReproPEL. Os CCOs submetidos aos dois meios foram submetidos à MIV e avaliados quanto à maturação nuclear e citoplasmática, ativação partenogenética e ao teste cometa. Na MIV nuclear, as maiores taxas de MII (P<0,05) foram obtidas no DPBS+ (63,1%), ReproPELc (55,1%) e ReproPEL+ (50,2%). Quanto à densidade dos GC, os grupos com menor área (P<0,05), evidenciando melhor migração, foram ReproPELc, D-PBS+, D-PBS- e ReproPEL+. A ativação partenogenética demonstrou que o meio ReproPEL possui boa capacidade de manutenção oocitária, possibilitando taxas aceitáveis de desenvolvimento até o estágio de blastocisto: ReproPEL+ (13,0%); e ReproPELc (12,7%). Desta forma, o meio ReproPEL pode ser indicado para a manutenção oocitária, porém não foi o meio mais indicado para o corante BCB. Com relação à toxicidade, após a exposição ao BCB e após a MIV, os oócitos BCB apresentaram alterações em nível mitocondrial, devido ao aumento na produção de ROS, diminuição do potencial de membrana e ao comprometimento da produção de ATP. Porém, a função mitocondrial foi restaurada no início do desenvolvimento embrionário. Com tudo isso, conclui-se que o BCB foi responsável por toxicidade em oócitos suínos imaturos, sendo necessários novos estudos para avaliar as alterações causadas pelo BCB em nível embrionário.

<p>This thesis addresses assembly issues encountered in optical and fluidic microsystem applications.</p><p>In optics, the first subject concerns the active alignment of components in optical fibersystems. A solution for reducing the cost of optical component assembly while retaining submicron accuracy is to integrate the alignment mechanism onto the optical substrate. A polymer V-shaped actuator is presented that can carry the weight of the large components - on a micromechanical scale - and that can generate movement with six degrees of freedom.</p><p>The second subject in optics is the CMOS-compatible fabrication of monocrystalline silicon micromirror arrays that are intended to serve as CMOS-controlled high-quality spatial light modulators in maskless microlithography systems. A wafer-level assembly method is presented that is based on adhesive wafer bonding whereby a monocrystalline layer is transferred onto a substrate wafer in a CMOS-compatible process without needing bond alignment.</p><p>In fluidics, a hybrid assembly method is introduced that combines two separately micromachined structures to create hotwire anemometers that protrude from a surface with minimum interference with the air flow. The assembled sensor enables one to make accurate time-resolved measurements of the wall shear stress, a quantity that has previously been hard to measure with high time resolution. Also in the field of hotwire anemometers, a method using a hotwire anemometer array is presented for measuring the mass flow, temperature and composition of a gas in a duct.</p><p>In biochemistry, a bio-analysis chip is presented. Single nucleotide polymorphism scoring is performed using dynamic allele-specific hybridization (DASH). Using monolayers of beads, multiplexing based on single-bead analysis is achieved at heating rates more than 20 times faster than conventional DASH provides.</p><p>Space and material e±ciency in packaging are the focus of the other two projects in fluidics. The first introduces an assembly based on layering conductive adhesives for the fabrication of miniature polymer electrolyte membrane fuel cells. The fuel cells made with this low-cost approach perform among the best of their type to date. The second project concerns a new cross-flow microvalve concept. Intended as a step towards the mass production of large-flow I/P converters, the silicon footprint area is minimized by an out-of-plane moving gate and in-plane, half-open pneumatic channels.</p>

This thesis addresses assembly issues encountered in optical and fluidic microsystem applications. In optics, the first subject concerns the active alignment of components in optical fibersystems. A solution for reducing the cost of optical component assembly while retaining submicron accuracy is to integrate the alignment mechanism onto the optical substrate. A polymer V-shaped actuator is presented that can carry the weight of the large components - on a micromechanical scale - and that can generate movement with six degrees of freedom. The second subject in optics is the CMOS-compatible fabrication of monocrystalline silicon micromirror arrays that are intended to serve as CMOS-controlled high-quality spatial light modulators in maskless microlithography systems. A wafer-level assembly method is presented that is based on adhesive wafer bonding whereby a monocrystalline layer is transferred onto a substrate wafer in a CMOS-compatible process without needing bond alignment. In fluidics, a hybrid assembly method is introduced that combines two separately micromachined structures to create hotwire anemometers that protrude from a surface with minimum interference with the air flow. The assembled sensor enables one to make accurate time-resolved measurements of the wall shear stress, a quantity that has previously been hard to measure with high time resolution. Also in the field of hotwire anemometers, a method using a hotwire anemometer array is presented for measuring the mass flow, temperature and composition of a gas in a duct. In biochemistry, a bio-analysis chip is presented. Single nucleotide polymorphism scoring is performed using dynamic allele-specific hybridization (DASH). Using monolayers of beads, multiplexing based on single-bead analysis is achieved at heating rates more than 20 times faster than conventional DASH provides. Space and material e±ciency in packaging are the focus of the other two projects in fluidics. The first introduces an assembly based on layering conductive adhesives for the fabrication of miniature polymer electrolyte membrane fuel cells. The fuel cells made with this low-cost approach perform among the best of their type to date. The second project concerns a new cross-flow microvalve concept. Intended as a step towards the mass production of large-flow I/P converters, the silicon footprint area is minimized by an out-of-plane moving gate and in-plane, half-open pneumatic channels. / QC 20101019

There are several methods for the full-wave characterization of waveguide discontinuities; Finite Element Method (FEM), Finite Difference Technique (FDT), and Method of Moments (MoM) are popular. However, these methods are not easily applied when studying the modal anatomy of a discontinuity. Other full-wave techniques are better suited. This dissertation discusses the formulation of a technique known as Generalized Transverse Resonance (GTR), which is a subset of Method of Moments. Generalized Transverse Resonance is a hybrid method combining the Transverse Resonance Method (TRM) with the Mode Matching Technique (MMT). The understanding of the generalized transverse resonance method starts with a discussion of Longitudinal Section Waves and from this derives the transverse resonance method for layered media para1lel to the wave propagation. It is shown that Maxwells equations can be represented as a mode function and voltage or current. This representation is used to reduce to the problem of merging the TRM and MMT into the GTR method by using network theory. The propagation constant is found by solving the wave equation, as an eigenvalue problem, subject to the boundary conditions. Discussed is the relative convergence phenomenon followed by the optimization strategy. Once the propagation constant is found, the cross sectional fields can be solved and from the fields the characteristic impedance is found. Theoretical data is compared to measure data to show the accuracy of the GTR method. Presented is an understanding of the propagation characteristics of a CPW transmission line in proximity with high and low loss silicon. This data will show the loss and propagation characteristics for four CPW structures using two separate silicon lids at six different heights above the transmission line. Two modes have been clearly identified and will be explained.