Chalcogenide Glass-on-Graphene Photonics

Two-dimensional (2-D) materials are of tremendous interest to integrated photonics given their singular optical characteristics spanning light emission, modulation, saturable absorption, and nonlinear optics. To harness their optical properties, these atomically thin materials are usually attached onto prefabricated devices via a transfer process. In this paper, we present a new route for 2-D material integration with planar photonics. Central to this approach is the use of chalcogenide glass, a multifunctional material which can be directly deposited and patterned on a wide variety of 2-D materials and can simultaneously function as the light guiding medium, a gate dielectric, and a passivation layer for 2-D materials. Besides claiming improved fabrication yield and throughput compared to the traditional transfer process, our technique also enables unconventional multilayer device geometries optimally designed for enhancing light-matter interactions in the 2-D layers. Capitalizing on this facile integration method, we demonstrate a series of high-performance glass-on-graphene devices including ultra-broadband on-chip polarizers, energy-efficient thermo-optic switches, as well as graphene-based mid-infrared (mid-IR) waveguide-integrated photodetectors and modulators

Novel Metamaterials and Their Applications in Subwavelength Waveguides, Imaging and Modulation

The development of metamaterials has opened the door for engineering electromagnetic properties by subwavelength artificial atoms , and hence accessing new properties and functionalities which cannot be found among naturally occurring materials. In particular, metamaterials enable the flexibility of independently controlling the permittivity and permeability to be almost any arbitrary value, which promises to achieve deep subwavelength confinement and focusing of electromagnetic waves in different spectrum regimes. The next stage of this technological revolution will be focused on the development of active and controllable metamaterials, where the properties of the metamaterials are expected to be tuned by external stimuli. In this sense, some natural materials are also promising to provide the tunable capability, particularly in the near infrared and terahertz domains either by applying a voltage or shining light on the materials. The objective of this dissertation is to investigate novel metamaterials and explore three important applications of them: subwavelength waveguiding, imaging and modulation. The first part of this dissertation covers the theory, design and fabrication of several different types of metamaterials, which includes artificially designed metamaterials and some naturally existing materials. The second part demonstrates metal gratings functioning as designer surface plasmonic waveguides support deep subwavelength surface propagation modes at microwave frequency. The third part proposes multilayered metal-insulator stack as indefinite metamaterial that converts evanescent waves to propagating waves, hence deep subwavelength image can be observed. The fourth part explores the tunability of several natural materials - gallium (Ga), indium tin oxide (ITO) and graphene, and demonstrates electro-optical (EO) modulators based on these materials can be achieved on nano-scale. The final part summarizes the work presented in this dissertation and also discusses some future work for photodetection, photovoltaics, and modulation

Toward a new generation of photonic devices based on the integration of metal oxides in silicon technology

[ES] La búsqueda de nuevas soluciones e ideas innovadoras en el campo de la fotónica de silicio mediante la integración de nuevos materiales con prestaciones únicas es un tema de alta actualidad entre la comunidad científica en fotónica y con un impacto potencial muy alto. Dentro de esta temática, esta tesis pretende contribuir hacia una nueva generación de dispositivos fotónicos basados en la integración de óxidos metálicos en tecnología de silicio. Los óxidos metálicos elegidos pertenecen a la familia de óxidos conductores transparentes (TCO), concretamente el óxido de indio y estaño (ITO) y el óxido de cadmio (CdO), y materiales de cambio de fase (PCM) como el dióxido de vanadio (VO2). Dichos materiales se caracterizan especialmente por una variación drástica de sus propiedades optoelectrónicas, tales como la resistividad o el índice de refracción, frente a un estímulo externo ya sea en forma de temperatura, aplicación de un campo eléctrico o excitación óptica. De esta forma, nuestro objetivo es diseñar, fabricar y demostrar experimentalmente nuevas soluciones y dispositivos clave tales como dispositivos no volátiles, desfasadores y dispositivos con no linealidad óptica. Tales dispositivos podrían encontrar potencial utilidad en diversas aplicaciones que comprenden las comunicaciones ópticas, redes neuronales, LiDAR, computación, cuántica, entre otros. Las prestaciones clave en las que se pretende dar un salto disruptivo son el tamaño y capacidad para una alta densidad de integración, el consumo de potencia, y el ancho de banda.[CA] La recerca de noves solucions i idees innovadores al camp de la fotònica de silici mitjançant la integració de nous materials amb prestacions úniques és un tema d'alta actualitat entre la comunitat científica en fotònica i amb un impacte potencial molt alt. D'aquesta temàtica, aquesta tesi pretén contribuir cap a una nova generació de dispositius fotònics basats en la integració d'òxids metàl·lics en tecnologia de silici. Els òxids metàl·lics elegits pertanyen a la família d'òxids conductors transparents (TCO), concretament l'òxid d'indi i estany (ITO) i l'òxid de cadmi (CdO), i materials de canvi de fase (PCM) com el diòxid de vanadi (VO2). Aquests materials es caracteritzen especialment per una variació dràstica de les propietats optoelectròniques, com ara la resistivitat o l'índex de refracció, davant d'un estímul extern ja siga en forma de temperatura, aplicació d'un camp elèctric o excitació òptica. D'aquesta manera, el nostre objectiu és dissenyar, fabricar i demostrar experimentalment noves solucions i dispositius clau com ara dispositius no volàtils, desfasadors i dispositius amb no-linealitat òptica. Aquests dispositius podrien trobar potencial utilitat en diverses aplicacions que comprenen les comunicacions òptiques, xarxes neuronals, LiDAR, computació, quàntica, entre d'altres. Les prestacions clau en què es pretén fer un salt disruptiu són la grandària i la capacitat per a una alta densitat d'integració, el consum de potència i l'amplada de banda.[EN] The search for new solutions and innovative ideas in the field of silicon photonics through the integration of new materials featuring unique optoelectronic properties is a hot topic among the photonics scientific community with a very high potential impact. Within this topic, this thesis aims to contribute to a new generation of photonic devices based on the integration of metal oxides in silicon technology. The chosen metal oxides belong to the family of transparent conducting oxides (TCOs), namely indium tin oxide (ITO) and cadmium oxide (CdO), and phase change materials (PCMs) such as vanadium dioxide (VO2). These materials are characterized by a drastic variation of their optoelectronic properties, such as resistivity or refractive index, in response to an external stimulus either in the form of temperature, application of an electric field, or optical excitation. Therefore, our objective is to design, fabricate and experimentally demonstrate new solutions and key devices such as non-volatile devices, phase shifters, and devices with optical nonlinearity. Such devices could find potential utility in several applications, including optical communications, neural networks, LiDAR, computing, and quantum. The key features in which we aim to take a leapfrog are footprint and capacity for high integration density, power consumption, and bandwidth.This work is supported in part by grants ACIF/2018/172 funded by Generaliltat Valenciana, and FPU17/04224 funded by MCIN/AEI/10.13039/501100011033 and by “ESF Investing in your future”.Parra Gómez, J. (2022). Toward a new generation of photonic devices based on the integration of metal oxides in silicon technology [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/19088

Graphene Based Waveguides

Graphene, which is well known as a one-atom thick carbon allotrope, has drawn lots of attention since its first announcement due to remarkable performance in mechanical, electrical, magnetic, thermal, and optical areas. In particular, unique properties of graphene such as low net absorption in broadband optical band, notably high nonlinear optical effects, and gate-variable optical conductivity make it an excellent candidate for high speed, high performance, and broadband electronic and photonics devices. Embedding graphene into optical devices longitudinally would enhance the light-graphene interaction, which shows great potential in photonic components. Since the carrier density of graphene could be tuned by external gate voltage, chemical doping, light excitation, graphene-based waveguide modulator could be designed to have high flexibility in controlling the absorption and modulation depth. Furthermore, graphene-based waveguides could take advantages in detection, sensing, polarizer, and so on

Modern Applications in Optics and Photonics: From Sensing and Analytics to Communication

Optics and photonics are among the key technologies of the 21st century, and offer potential for novel applications in areas such as sensing and spectroscopy, analytics, monitoring, biomedical imaging/diagnostics, and optical communication technology. The high degree of control over light fields, together with the capabilities of modern processing and integration technology, enables new optical measurement systems with enhanced functionality and sensitivity. They are attractive for a range of applications that were previously inaccessible. This Special Issue aims to provide an overview of some of the most advanced application areas in optics and photonics and indicate the broad potential for the future

Silicon - polymer hybrid integrated microwave photonic devices for optical interconnects and electromagnetic wave detection

textThe accelerating increase in information traffic demands the expansion of optical access network systems that require high-performance optical and photonic components. In short-range communication links, optical interconnects have been widely accepted as a viable approach to solve the problems that copper based electrical interconnects have encountered in keeping up with the surge in the data rate demand over the last decades. Low cost, ease of fabrication, and integration capabilities of low optical-loss polymers make them attractive for integrated photonic applications to support futuristic data communication networks. In addition to passive wave-guiding components, electro-optic (EO) polymers consisting of a polymeric matrix doped with organic nonlinear chromophores have enabled wide-RF-bandwidth and low-power active photonic devices. Beside board level passive and active optical components, on-chip micro- or nano-photonic devices have been made possible by the hybrid integration of EO polymers onto the silicon platform. In recent years, silicon photonics have attracted a significant amount of attentions, because it offers compact device size and the potential of complementary metal–oxide–semiconductor (CMOS) compatible photonic integrated circuits. The combination of silicon photonics and EO polymers can enable miniaturized and high-performance hybrid integrated photonic devices, such as electro-optic modulators, optical interconnects, and microwave photonic sensors. Silicon photonic crystal waveguides (PCWs) exhibit slow-light effects which are beneficial for device miniaturization. Especially, EO polymer filled silicon slotted PCWs further reduce the device size and enhance the device performance by combining the best of these two systems. The potential applications of these silicon-polymer hybrid integrated devices include not only optical interconnects, but also optical sensing and microwave photonics. In this dissertation, the design, fabrication, and characterization of several types of silicon-polymer hybrid photonic devices will be presented, including EO polymer filled silicon PCW modulators for on-chip optical interconnects, antenna-coupled optical modulators for electromagnetic wave detections, and low-loss strip-to-slot PCW mode converters. In addition, some polymer-based devices and silicon-based photonic devices will also be presented, such as traveling wave electro-optic polymer modulators based on domain-inversion directional couplers, and silicon thermo-optic switches based on coupled photonic crystal microcavities. Furthermore, some microwave (or RF) components such as integrated broadband bowtie antennas for microwave photonic applications will be covered. Some on-going work or suggested future work will also be introduced, including in-device pyroelectric poling for EO polymer filled silicon slot PCWs, millimeter- or Terahertz-wave sensors based on EO polymer filled plasmonic slot waveguide, low-loss silicon-polymer hybrid slot photonic crystal waveguides fabricated by CMOS foundry, logic devices based on EO polymer microring resonators, and so on.Electrical and Computer Engineerin