El silicio es la plataforma más prometedora para la integración fotónica, asegurando la compatibilidad con los procesos de fabricación CMOS y la producción en masa de dispositivos a bajo coste. Durante las últimas décadas, la tecnología fotónica basada en la plataforma de silicio ha mostrado un gran crecimiento, desarrollando diferentes tipos de dispositivos ópticos de alto rendimiento. Una de las posibilidades para continuar mejorando las prestaciones de los dispositivos fotónicos es mediante la combinación con otras tecnologías como la plasmónica o con nuevos materiales con propiedades excepcionales y compatibilidad CMOS. Las tecnologías híbridas pueden superar las limitaciones de la tecnología de silicio, dando lugar a nuevos dispositivos capaces de superar las prestaciones de sus homólogos electrónicos. La tecnología híbrida dióxido de vanadio/ silicio permite el desarrollo de dispositivos de altas prestaciones, con gran ancho de banda, mayor velocidad de operación y mayor eficiencia energética con dimensiones de la escala de la longitud de onda. El objetivo principal de esta tesis ha sido la propuesta y desarrollo de dispositivos fotónicos de altas prestaciones para aplicaciones de conmutación. En este contexto, diferentes estructuras basadas en silicio, tecnología plasmónica y las propiedades sintonizables del dióxido de vanadio han sido investigadas para controlar la polarización de la luz y para desarrollar otras funcionalidades electro-ópticas como la modulación. / Silicon is the most promising platform for photonic integration, ensuring CMOS fabrication compatibility and mass production of cost-effective devices. During the last decades, photonic technology based on the Silicon on Insulator (SOI) platform has shown a great evolution, developing different sorts of high performance optical devices. One way to continue improving the performance of photonic optical devices is the combination of the silicon platform with another technologies like plasmonics or CMOS compatible materials with unique properties. Hybrid technologies can overcome the current limits of the silicon technology and develop new devices exceeding the performance metrics of its counterparts electronic devices. The vanadium dioxide/silicon hybrid technology allows the development of new high-performance devices with broadband performance, faster operating speed and energy efficient optical response with wavelength-scale device dimensions. The main goal of this thesis has been the proposal and development of high performance photonic devices for switching applications. In this context, different structures, based on silicon, plasmonics and the tunable properties of vanadium dioxide, have been investigated to control the polarization of light and for enabling other electro-optical functionalities, like optical modulation. / El silici és la plataforma més prometedora per a la integració fotònica, assegurant la compatibilitat amb els processos de fabricació CMOS i la producció en massa de dispositius a baix cost. Durant les últimes dècades, la tecnologia fotònica basada en la plataforma de silici ha mostrat un gran creixement, desenvolupant diferents tipus de dispositius òptics d'alt rendiment. Una de les possibilitats per a continuar millorant el rendiment dels dispositius fotònics és per mitjà de la combinació amb altres tecnologies com la plasmònica o amb nous materials amb propietats excepcionals i compatibilitat CMOS. Les tecnologies híbrides poden superar les limitacions de la tecnologia de silici, donant lloc a nous dispositius capaços de superar el rendiment dels seus homòlegs electrònics. La tecnologia híbrida diòxid de vanadi/silici permet el desenvolupament de dispositius d'alt rendiment, amb gran ample de banda, major velocitat d'operació i major eficiència energètica en l'escala de la longitud d'ona. L'objectiu principal d'esta tesi ha sigut la proposta i desenvolupament de dispositius fotònics d'alt rendiment per a aplicacions de commutació. En este context, diferents estructures basades en silici, tecnologia plasmònica i les propietats sintonitzables del diòxid de vanadi han sigut investigades per a controlar la polarització de la llum i per a desenvolupar altres funcionalitats electró-òptiques com la modulació. / Sánchez Diana, LD. (2016). High performance photonic devices for switching applications in silicon photonics [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/77150 / TESIS

<div>The purpose of this thesis was to investigate the possibility of Optical Frequency Identification (OFID) technology being used as a communication pathway for devices in LiFi systems that serve to open alternative transmission paths for Internet-of-Things infrastructure. LiFi or light-fidelity, plays off the concept of wireless-fidelity, commonly known as WiFi, and follows the trend of moving to higher frequencies within the electromagnetic spectrum. LiFi lies within the visual light and infrared wavelength range, which can be referred to as the nanometer wave range. The developed optical communication testbed is a proof of concept showing that OFID technology, enabled by Gallium Arsenide solar cell emission, can communicate with Visual Light Communication (VLC) systems. The scope of the work entails the development of a testbed for a custom optical communications testbed for OFID linked to VLC communication by sending transmissions via powerline modulation. An optical receiver circuit was developed and tested, and integration and testing for powerline communication and LED luminaire were successful. Manchester encoded data was sent at 4800 bit rate optically from an infrared light source, received by the developed receivers and was decoded. Information was successfully transmitted over powerline from computer terminal to LED luminaire output at 2400, 3600, 4800, 7200, and 9600 bit rate. Integration of these communication links did not occur due to Purdue University closure of campus related activities from COVID-19.<br></div>

L’augmentation des capacités des systèmes de télécommunications optiques passe par le développement des dispositifs optoélectroniques innovants et des technologies clés à hautes performances. Ces dispositifs sont sujets à une forte intégration des composants et les technologies déployées mettent en œuvre des fonctions complexes (PDM – QPSK, PDM – 16 QAM, etc.). Il est donc nécessaire avant toute réalisation d’étudier le comportement électromagnétique de ces composants afin d’envisager des performances en haute fréquence et une bonne intégrité du signal contenant l’information dans la chaîne de transmission. Ainsi à travers une modélisation EM – circuit le comportement global d’un modulateur à plusieurs niveaux de phase, basé sur la déplétion de porteurs dans une jonction PN, est étudié et analysé. Le modulateur est dans un premier temps représenté par un modèle prenant en compte la jonction. Cette dernière est modélisée par sa résistance et sa capacité équivalentes. Ensuite le packaging du modulateur avec son circuit d’entrée pour les signaux RF et son circuit de sortie pour l’adaptation de charges en sortie est réalisé et optimisé. Une modélisation EM a également permis de concevoir le circuit d’entrée d’un multiplexeur intégré à un Convertisseur Numérique – Analogique 3 bits, destiné à mettre œuvre une modulation PDM – 64 QAM dans un système optique. Les résultats obtenus respectent les spécifications industrielles et permettent de d’envisager le fonctionnement en haute fréquence des dispositifs intégrés. / The increase of the capacities of optical telecommunications systems goes through the development of innovative optoelectronics devices and key technologies with high performances. These devices are subjects to high components integration and the deployed technologies implement complex functions (PDM - QPSK, PDM - 16 QAM etc.). Therefore, it is necessary before any realization to study the electromagnetic behavior of these components in order to predict good performances at high frequency and signal integrity in the transmission chain. Thus, through an EM - circuit modeling, the overall behavior of an electro-optical multilevel modulator based on carrier depletion in a PN junction has been studied and analyzed. The modulator is firstly represented by a model taking in account the junction. The junction is modeled by her equivalents resistance and capacity. Subsequently, the packaging of the modulator with the input and out circuit is realized and optimized. The EM modeling has also helped to design the input circuit of an integrated multiplexer to a 3 bits digital - analog converter for an optical system. The obtained results meet the industry specifications and allow predicting good performances in high frequency for the integrated devices.

No description available.

<p>Management of incoming solar radiation and use of the sky as an ultimate heat sink are technological imperatives as climate change shifts our reliance from fossil fuels to sustainable sources.  Selective solar absorbers are a possible route for solar harvesting as they collect the incoming radiation for process heat or space heating.  Here, improvement in the performance of selective solar absorbers via photon recycling is investigated using a stepped index rugate filter.  The final proposed filter when integrated with a high vacuum selective solar absorber could see an improvment in solar-thermal conversion efficiency from 13% to 30.6%. Then, a frequency selective optical filter is fabricated with uses including improvement of radiative coolers.  The measured optical characteristics are compared with simulation data and found to match well.</p> <p><br></p> <p>The shift to sustainable sources of electricity will require an expansion of the electrical grid.  The backbone of the grid for converting high voltage AC to DC, and vice versa, is power electronics.  The current state-of-the-art technology is GaN HEMTs, but GaN MISHEMTs are poised to replace them since MISHEMTs reduce the gate leakage current; a deficiency of the GaN HEMT architecture.  First, time dependent dielectric breakdown in GaN MISHEMTs is investigated using concurrent electrical and thermoreflectance methods.  A susceptibility in the MISHEMT architecture is found and possible solutions are proposed.  Then, liquid cooling of GaN HEMT PAs is explored by demonstrating integration of an X-band front end module, printed circuit board, and fluid manifold.  The integration shows great promise as two-phase cooling performance improved with increasing power dissipated, while single-phase cooling performance degraded.</p>

<p dir="ltr">Two-dimensional (2D) perovskite semiconductors are an emerging family of hybrid materials featuring a built-in quantum well architecture which has gained much interest due to its potential as a promising candidate for next-generation photovoltaic and optoelectronic applications. To successfully integrate 2D perovskites as efficient devices, it is imperative that a thorough understanding of the fundamental properties these materials possess and how their complex heterostructures behave is established. However, to date, the synthetic challenges regarding high-quality crystals of these materials due to the structural complexity and the hybrid nature have impeded further progress in this area. Thus, we demonstrate a general method to construct tunable 2D organic semiconductor-incorporated perovskites (OSiP) by simultaneously manipulating slab thickness of the inorganic layers and conjugation length of the organic substituents. The energy band offsets and exciton dynamics at the organic-inorganic interfaces were elucidated using computational means and ultrafast spectroscopy, while lattice dynamics were quantified via temperature-dependent spectroscopy and X-ray diffraction studies. Results show that longer and more planar π-conjugated organic ligands induce a more rigid inorganic crystal lattice, which leads to suppressed exciton-phonon interactions and superior optoelectronic properties such as efficient lasing.</p><p dir="ltr">Furthermore, understanding ion migration in two-dimensional (2D) perovskite materials is key to enhancing device performance and stability as well. However, prior studies have been primarily limited to heat and light-induced ion migration. To investigate electrically induced ion migration in 2D perovskites, we construct a high-quality single crystal 2D perovskite heterostructure device platform with near defect-free van der Waals contact. While achieving real-time visualization of directional ion migration, we also uncover the unique behavior of halide anions inter-diffusing towards the opposite direction under prolonged bias. Confocal microscopy imaging reveals a halide migration channel that aligns with the crystal and heterojunction edges. After sustained ion migration, stable junction diodes exhibiting up to ~1000-fold forward to reverse current ratio are realized. Unraveling the fundamental properties of 2D OSiPs as well as ion migration in 2D perovskite heterostructures paves the way towards stable and efficient devices.</p>

Cette thèse CIFRE adresse le développement de diodes laser, émettant à 975nm, de très forte puissance, rendement à la prise élevé, et stabilisées en longueur d’onde pour pompage de fibres dopées Er/Yb et réalisation de lasers à fibre. La thèse a été développée dans le cadre d’un partenariat étroit entre le Laboratoire IMS, le GIE III-V Lab, principal fondeur français de composants à semiconducteurs III-V pour des applications électroniques et photoniques, et THALES Research & Technology à Palaiseau en région parisienne. Un travail en profondeur de caractérisation et d’analyse a porté sur les aspects thermiques qui contribuent, en particulier,à limiter les niveaux de puissance optique de sortie. Dans ce cadre, nous avons réalisé un ensemble de caractérisations complémentaires au GIE III-V lab et à l’IMS nous permettant d’envisager des solutions correctives d’optimisation technologique portant en particulier sur la profondeur de gravure définissant la largeur de la zone d’émission et la nature du substrat dissipateur. Ces solutions ont été proposées à partir de modélisations physiques mises en oeuvre avec un simulateur dédié, propriété de III-V Lab et de simulations par éléments finis thermiques et thermomécaniques (approche multiphysique) de la structure microassemblée définitive. Ces travaux se sont prolongés par la fabrication et la caractérisation électro-optique et thermique de plusieurs structures verticales : LOC (Large Optical Cavity), SLOC (Super Large OpticalCavity) et AOC (Asymetrical Optical Cavity). Les diodes laser de type LOC et SLOC sont stabilisées en longueur d’onde en intégrant un réseau de Bragg (DFB). Une puissance optique de 8W avec une efficacité de 60% a été obtenue ; ce qui permet de situer ces travaux à l’état de l’art international notamment vis-à-vis de ceux publiés par l’Institut Ferdinand-Braun.L’originalité des travaux menés dans cette thèse nous a permis d’avoir accès à une bourse du Cluster européen « Laserlab » (The Integrated Initiative of European Laser Research Infrastructures), pour conduire des campagnes d’expérimentation à l’Institut Max Born à Berlin dans le groupe du Dr J.W. Tomm. Les travaux ont porté sur la caractérisation thermique de ces diodes laser de forte puissance émettant à 975nm, à double hétérostructure symétrique et asymétrique (SLOC et AOC), en utilisant des techniques complémentaires (microphotoluminescence,photoluminescence résolue en temps, spectroscopie de photocourant et mesures L-I pulsées) et permettant d’évaluer le type de contraintes résiduelles apportées par les étapes de report de la diode Laser ainsi que la cinétique de dégradation catastrophique de type COD. / This PhD addresses the development of high-power laser diodes emitting at 975nm withhigh efficiency and wavelength stabilized using a Bragg grating. This thesis was conducted in the framework of a close partnership between IMS Laboratory, the GIE III-V lab, who is themain French founder of III-V semiconductor devices for electronic and photonic applications,and THALES Research & Technology in Palaiseau. An in-depth characterization and analysiswork has addressed thermal aspects that contribute, in particular, to limit the optical outputpower of a laser diode. In such a context, we have carried out a set of complementary characterizations both at III-V lab and IMS allowing us to provide some corrective solutionsfor technological optimization concerning the etching depth of the grooves that defines the emitting stripe of the laser diode and the nature of the submount acting as a thermocompensator.These solutions have been proposed from optical modelling implemented with a dedicated simulator, property of III-V lab, and thermal and thermomechanical (multiphysics approach) finite element simulations of the overall microassembled structure. All this work has resulted in the fabrication as well as electro-optical and thermal characterizations of three vertical structures namely LOC (Large Optical Cavity), SLOC (Super Large Optical Cavity)and AOC (Asymmetrical Optical Cavity). The LOC and SLOC vertical structures have been processed with a Fabry-Perot cavity and also including a Bragg grating (DFB architecture) while the AOC one was only fabricated with a Fabry-Perot cavity. State-of-the-art results aredemonstrated since in particular an optical power of 8W with an efficiency of 60% has been obtained that can be compared to those recently published by the Ferdinand-Braun Institute.The originality of the work carried out in this PhD has allowed us to receive a grant from the European Laserlab Cluster (The Integrated Initiative of the European Laser Research Infrastructures), to conduct dedicated experiments at the Max-Born Institute (Berlin) in thegroup of Dr. J.W. Tomm. The work aimed to characterize mechanical strain of the laser diode induced by the soldering process. Two vertical structures (SLOC and AOC) were investigated using complementary techniques (microphotoluminescence, time-resolved photoluminescence,photocurrent spectroscopy and pulsed L-I measurements), allowing to quantify the level of residual stress provided by the laser diode mounting process as well as the kinetics of the catastrophic degradation process (COD).

Neste trabalho foram projetados, fabricados e caracterizados funcionalmente dispositivos eletroluminescentes empregando complexos de Terras Raras (TR) e de Metais de Transição (MT) tanto como em filmes finos termicamente evaporados quanto formados através da técnica de spin-coating. O estudo foi iniciado com os complexos de TRs (especificamente o complexo de Európio e de Térbio) com filmes termicamente evaporados, com vistas à análise da eficiência externa dos dispositivos em função do ligante principal (CL). Desta análise observou-se que a particular estrutura química do CL resulta em diferenças perceptíveis ao nível da caracterização eletro-óptica (de 0,73x10-3 [BTA] para 1,05x10-3 [DBM]). Dando seqüência à análise de dispositivo com camada emissiva termicamente evaporada, foi realizada a análise do complexo de Térbio com dois tipos de ligante neutro (NL). Com base nos resultados obtidos, neste foco do estudo, observou-se que a configuração estrutural do NL implica em diferenças na eficiência externa (de 0,8x10-3 [PHEN] para 4,1x10- 3 [BIPY]) e no comprimento de onda dominante emitido (de 542 nm [BIPY] para 563 [PHEN]). Ainda explorando os complexos de TRs, foram estudados dispositivos empregando estes dispersos em um polímero com função de matriz, neste caso o polivinilcarbazol (PVK), em filmes formados por spin-coating, os quais apresentaram maior eficiência (de 0,72x10-3 [evaporado] para 1,24x10-3 [spincoating]) externa em comparação aos termicamente evaporados. Ainda nesta linha de estudo foi explorada uma nova estrutura de dispositivo empregando filmes automontados, cujos resultados apresentaram uma melhor eficiência externa para três bicamadas de PAni/PEDOT:PSS. Na seqüência, foram empregados os complexos de MT, especificamente de Rutênio e de Rênio, em filmes finos formados por spincoating. Com o primeiro destes, foi avaliada a conseqüência da variação do seu ligante, seus processos de transporte de portadores de carga e os fenômenos relacionados com sua luminescência. Já com o segundo, que foi disperso em PVK em diversas concentrações, foi feita a análise da eficiência externa com a mesma idéia adotada com o complexo de Európio, cujo estudo revelou uma eficiente transferência de energia, descrita pelo mecanismo de Transferência de Carga Metal- Ligante (3MLCT). / This work presents the study of the Rare Earth (RE) and Transition Metals (TM) complexes, as emissive layers of Organic Light-Emitting Devices (OLEDs) designed, built and electro-optically characterized. The thin films were thermally evaporated or spin-coated. This research started with the study of Europium complex changing its central ligand (CL), which showed that its electrical response exhibits external efficiency differences (from 0.73x10-3 [BTA] to 1.05x10-3 [DBM]). It was observed that the particular chemical structure of the CL results in significant differences as seen in the electro-optical characterization. Giving continuity to the thermally evaporated device characterization, an analysis was done with the Terbium complexes with two different neutral ligands (NL). It was noticed, in this work, that an NL change in Terbium complex imply in changes in external efficiency (from 0.8x10-3 [PHEN] to 4.1x10-3 [BIPY]) and in the emitted dominant wavelength (from 542 nm [BIPY] to 563 nm [PHEN]). Following the study using RE complex, we used it as a dye dispersed in polyvinylcarbazole (PVK) matrix, in a spin-coated deposited thin-film, which results showed a better external efficiency in comparison with thermally evaporated thin-films (from 0.72x10-3 [thermal evaporation] to 1.24x10-3 [spin-coating]). Besides, it was studied a new structure of electroluminescent device with thin-film Self-Assembled deposition, which results showed a better external efficiency for three bilayers of PAni/PEDOT:PSS. In the sequence, TM complexes, namely Ruthenium and Rhenium, were studied using spincoated thin-films. With the first of them, the implications of different ligands (bipyridyne and phenanthroline) were evaluated aiming the charge carrier transport and the luminescence related phenomena. The Rhenium complex was dispersed as a dye in the PVK, using the same approach as that used to study the Europium complex showing a very efficient energy transfer process, described in literature as the Metal-Ligand Charge Transfer (3MLCT) mechanism.

This thesis is devoted to the optical properties of low-dimensional structures based on such two-dimensional materials as graphene, silicene and phosphorene. We investigate optical properties of a variety of quasi-one dimensional and quasi-zero-dimensional structures, which are promising for future optoelectronics. Primarily we focus on their low-energy optical properties and how these properties are influenced by the structures’ geometry, external fields, intrinsic strain and edge disorder. As a consequence of this endeavor, we find several interesting effects such as correlation between the optical properties of tubes and ribbons whose periodic and ‘hard wall’ boundary conditions are matched and a universal value of matrix element in narrow-gap tubes and ribbons characterizing probability of transitions across the band gap opened up by intrinsic strain originating from the tube’s surface curvature or ribbon’s edge relaxation. The analytical study of the gapped 2D Dirac materials such as silicene and germanene, which have some similarity to the aforementioned quasi-one-dimensional systems in terms of physical description, reveals a valley- and polarization-dependent selection rules. It was also found that absorption coefficient should change in gapped materials with increasing frequency and become a half of its value for gap edge transitions when the spectrum is linear. Our analysis of the electronic properties of flat clusters of silicene and phosphorene relates the emergence and the number of the peculiar edge states localized at zero energy, so-called zero-energy states, which are know to be of topological origin, to the cluster’s structural characteristics such as shape and size. This allows to predict the presence and the number of such states avoiding complicated topological arguments and provides a recipes for design of metallic and dielectric clusters. We show that zero-energy states are optically active and can be efficiently manipulated by external electric field. However, the edge disorder is important to take into account. We present a new fractal-based methodology to study the effects of the edge disorder which can be applied also to modeling of composite materials. These finding should be useful in design of optoelectronic devices such as tunable emitters and detectors in a wide region of electromagnetic spectrum ranging form the mid-infrared and THz to the optical frequencies.

<p><a>The quick, reliable, and sensitive detection of bacterial contamination is desired in areas such as counter bioterrorism, medicine, and food/water safety as pathogens such as<i> E. coli</i> can cause harmful effects with the presence of just a few cells. However, standard high sensitivity techniques require laboratories and trained technicians, requiring significant time and expense. More desirable would be a sensitive point-of-care device that could detect an array of pathogens without sample pre-treatment, or a continuous monitoring device operating without the need for frequent operator intervention.<br> <br> Optical microring resonators in silicon photonic platforms are particularly promising as scalable, multiplexed refractive index sensors for an integrated biosensing array. However, no systematic effort has been made to optimize the sensitivity of microrings for the detection of relatively large discrete analytes such as bacteria, which differs from the commonly considered cases of fluid or molecular sensitivity. This work demonstrates the feasibility of using high finesse microrings to detect whole bacterial cells with single cell resolution over a full range of potential analyte-to-sensor binding scenarios. Sensitivity parameters describing the case of discrete analyte detection are derived and used to guide computational optimization of microrings and their constituent waveguides, after considering a range of parameters such as waveguide dimension, material, modal polarization, and ring radius. The sensitivity of the optimized 2.5 µm radius silicon TM O-band ring is experimentally demonstrated with photoresist cellular simulants. A multiplexed optimized ring array is then shown to detect <i>E. Coli</i> cells in an experimental proof of concept.</a></p>