Integrated photonics for millimetre wave transmitters and receivers

This PhD thesis entitled “Integrated photonics for millimetre wave transmitters and receivers” aimed at investigating the possibility of employing the uni-traveling carrier photodiode (UTC-PD) in millimetre wave (MMW) wireless receivers and, eventually, demonstrating a photonic integrated transceiver, by exploiting the concept of optically-pumped mixing (OPM). Previously, the UTC-PD has been successfully demonstrated as an OPM, by mixing an optically-generated local oscillator (LO) with a high frequency RF signal to generate a replica of the RF signal at a low intermediate frequency (IF), defined by the difference between the LO and the RF signal. This concept forms the foundation of this PhD thesis. The principal idea is to deploy the UTC-PD mixer in MMW wireless receivers to down-convert the high frequency data signal into a low frequency IF, where it can be easily processed and recovered. The main challenge to this approach is the low conversion efficiency of the UTC-PD mixer. For example, a conversion loss of 32 dB has been reported at 100 GHz. Also, the detection bandwidth in previous demonstrations was very narrow (around 100 Hz), which is too narrow to be useful in high-speed data communications. Consequently, a significant effort was made, in this thesis, to improve these parameters before the implementation in wireless receivers. The characterization and optimization works done in this thesis on the input parameters to the UTC-PD mixer have advanced the state of the art significantly. For example, conversion losses as low as 22 dB have been reported here. Also, the detection bandwidth has been increased to up to 10 GHz, allowing for multi-Gbps communication links. Based on these promising results, proof of concept wireless data transmission experiments were successfully conducted at different carrier frequencies (33 GHz, 35 GHz, and 60 GHz) using separate non-integrated UTC-PDs at the receiver with speeds of up to 5 Gbps. To the best of the author’s knowledge, this is the first demonstration of the UTC-PD at the receiver. Upon these successful demonstrations, further research was done on a photonic integrated circuit, which comprises UTC-PDs, lasers, optical amplifiers and modulators. The outcome of this research was the first demonstration of a photonic integrated transceiver. This transceiver is suitable for short distance communications and could find interesting applications in 5G and future networks, including: high definition (HD) video streaming, file transfer, and wireless backhaul

Exploration of Nonlinear Devices and Nonlinear Transmission Line Techniques for Microwaves Applications

RÉSUMÉ Les systèmes de communication modernes dépendent fortement des circuits non linéaires, tels que les amplificateurs de puissance (PA), les mélangeurs, les multiplicateurs, les oscillateurs, les commutateurs, etc., qui sont construits à partir de composants non linéaires passifs (comme des diodes) ou actifs (par exemple des transistors). Cette thèse étudie les dispositifs non linéaires passifs traditionnels et émergents, ainsi que les techniques de lignes de transmission non linéaires (NLTL). Plusieurs de leurs applications micro-ondes ont également été étudiées, y compris la récupération d'énergie sans fil, la synthèse d’impédance électronique et l’adaptation d’impédance bidimensionnelle (inductive et capacitive). Dans le chapitre 1, sont d'abord étudiés les dispositifs non linéaires traditionnels résistifs, capacitifs et inductifs. Les dispositifs non linéaires émergents, y compris les dispositifs MEMS et la spindiode, sont ensuite explorés. La construction physique de base, les principes de fonctionnement, ainsi que les caractéristiques et applications pour divers types de dispositifs non linéaires sont expliqués et comparés. Les lignes de transmission non-linéaires (NLTL) traditionnelles utilisant des dispositifs non linéaires capacitifs (varactor, BST etc.) ou inductifs (ferrite saturée), et la technique hybride NLTL émergente utilisant à la fois des dispositifs non linéaires capacitifs et inductifs sont également étudiées. Le chapitre 2 examine les techniques de conversion d'énergie micro-ondes à courant-continu de faible puissance à la fine pointe de la technologie. Une image complète de l'état de l'art sur cet aspect est donnée graphiquement. Elle compare différentes technologies telles que le transistor, la diode et les technologies CMOS. Depuis le tout début des techniques intégrées RF et micro-ondes et de la récupération d'énergie, les diodes Schottky ont été le plus souvent utilisées dans les circuits de mélange et de redressement. Cependant, dans des applications spécifiques de récupération d'énergie, la technique des diodes Schottky ne parvient pas à fournir une efficacité satisfaisante de conversion RF-dc. Suite aux limitations mises en évidence des dispositifs actuels, ce travail introduit, pour la première fois, un composant non linéaire pour une redressement de faible puissance, basé sur une découverte récente en spintronique, à savoir, la jonction tunnel magnétique, parfois appelée spindiode. Un modèle équivalent de spindiode est développé pour décrire le comportement en fréquence.----------ABSTRACT Modern communication systems are heavily dependent on nonlinear circuits, such as PA, mixer, multiplier, oscillator, switch, etc., the core of which are either passive nonlinear elements and devices (e.g. diodes) or active nonlinear components and devices (e.g. transistors). This thesis aims at investigating a number of traditional and emerging passive nonlinear devices and nonlinear transmission line (NLTL) techniques, and developing four of their microwave applications such as wireless power harvesting, electronic impedance synthesizer, and two-dimensional tuning circuit. In Chapter 1, traditional nonlinear devices in terms of the categories of resistive, capacitive and inductive are firstly investigated. Emerging nonlinear devices including microelectromechanical system (MEMS) devices and spindiodes are then explored. The basic physical constructions, operation principles, and characteristics as well as applications of various types of nonlinear devices are explained and compared. Traditional NLTL techniques make use of either capacitive nonlinear devices (varactor, BST etc.) or inductive nonlinear devices (saturated ferrite), and emerging hybrid NLTL techniques are also studied through the deployment of both nonlinear capacitive and inductive devices. Chapter 2 examines the state-of-the-art low-power microwave-to-dc energy conversion techniques. A comprehensive picture of the state-of-the-art on this aspect is given graphically, which compares different technologies such as transistor, diode, and CMOS schemes. Since the very beginning of RF and microwave integrated techniques and energy harvesting, Schottky diodes as the undisputable dominant choice, have been widely used in mixing and rectifying circuits. However, in specific μW power-harvesting applications, the Schottky diode technique seemingly fails to provide a satisfactory RF–dc conversion. Subsequent to the highlighted limitations of current devices, this work introduces, for the first time, a nonlinear component for low-power rectification based on a recent discovery in spintronics, namely, the Magnetic Tunnel Junction, also called spindiode. An equivalent model of spindiode is developed to describe the frequency behavior. Full parametric studies show that the interfacial capacitance, rather than the geometric capacitance, as it is usually the case for diode, plays a crucial role in the drop of efficiency in microwave frequency applications

New photonic architectures and devices for generation and detection of sub-THz and THz waves

The development of high-quality and reliable devices in the THz frequency region to fill the existing technological gap has become a major concern. This is chiefly motivated by the need of a widespread exploitation of the extensive variety of identified applications in this frequency region by a wide range of users, including the non-scientific community. The photonic approaches used for these purposes offer important and exclusive advantages over other existing alternatives, which have as a main representative the all-electronic technology, especially in terms of frequency range coverage, possibility of photonic distribution using optical fibers, weight and Electromagnetic Interference (EMI) immunity. Nevertheless, the optical techniques have traditionally provided with worse performance in terms of phase noise, tunability and dynamic range (in generation), and conversion ratio (in detection) when compared to state-of-theart all-electronic THz technology. The work accomplished in this thesis focuses on the design, development and validation of new photonic architectures and devices for both generation and detection of sub-THz and THz waves which overcome the drawbacks of optical techniques at this frequency region while maintaining all their advantages. In this thesis, several photonic sub-THz and THz generation systems have been developed using Difference Frequency Generation (DFG) architectures in which the DFG source is provided by an Optical Frequency Comb Generator (OFCG) and optical mode selection. Different devices and techniques are investigated for each part of the system before arriving to the final high performance synthesizer. Passively Mode-Locked Laser Diodes (PMMLDs) are firstly evaluated as integrated OFCG. An improved design of the OFCG is achieved with a scheme based on a Discrete Mode (DM) laser under Gain- Switching (GS) regime and optical span expansion by the use of a single Electro- Optical (EO) phase modulator. As optical mode selection, both high selective optical filtering and Optical Injection Locking (OIL) are used and evaluated. A commercial 50 GHz photodiode (PD) and an n-i-pn-i-p superlattice THz photomixer are employed as photodetector for Optical to THz conversion. The final reported system consists on an OFCG based on GS, OIL as mode selection strategy and an n-i-pn-i-p superlattice photomixer. This synthesizer offers a wide frequency range (60-140 GHz), readily scalable to a range between 10 GHz and values well above 1 THz. Quasi-continuous tunability is offered in the whole frequency range, with a frequency resolution of 0.1 Hz at 100 GHz that can be straightforwardly improved to 0.01 Hz at 100 GHz and 0.1 Hz at 1 THz. The measured FWHM at 120 GHz is <10 Hz, only limited by the measurement instrumentation. The system offers excellent frequency and power stability with frequency and power deviations over 1 hour of 5 Hz and 1.5 dB, respectively. These values are also limited by both the accuracy and uncertainty of the measurement setup. The performance achieved by this photonic sub-THz and THz synthesizer for most figures of merit matches or even surpasses those of commercial stateof- the-art all-electronic systems, and overcomes some of their characteristics in more than one million times when compared to commercial state-of-the-art photonic solutions. The detection part of this thesis explores the use of photonic architectures based on EO heterodyne receivers and the key devices that encompass these architectures: photonic Local Oscillators (LOs) and EO mixers. First results are developed at microwave frequencies (<15 GHz) using an Ultra-Nonlinear Semiconductor Amplifier (XN-SOA) as EO mixer and a GS based photonic LO. It is demonstrated how this LO device based on GS provides with a significant improvement in the performance of the overall EO receiver when compared to a traditional linearly modulated LO. Furthermore, this detection architecture is validated in an actual application (photonic imaging array), featuring scalability, flexibility and reasonable conversion ratios. After this, an EO heterodyne receiver is demonstrated up to frequencies of 110 GHz. The photonic LO employed is the abovementioned photonic sub- THz synthesizer developed in this thesis, while the EO mixer is an np-i-pn quasi ballistic THz detector. The first fabricated sample of this novel device is used, which is optimized for homodyne/heterodyne detection. The resulting sub-THz EO heterodyne receiver has conversion ratios around -75 dB. It works under zero-bias conditions, which together with the photonic distribution of the LO offers a high potential for remote detection of sub-THz and THz waves. In summary, new photonic architectures and devices are able to provide with state-of-the-art performance for generation of sub-THz and THz waves. In the case of EO heterodyne detection at sub-THz and THz frequency regions, photonic techniques are improving their performance and are closer to offer an alternative to all-electronic detectors. ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------El desarrollo de dispositivos fiables y de alta calidad en el rango frecuencial de Terahercios (THz) con el fin de cubrir el actual vacío tecnológico se ha convertido en una importante inquietud científica. Esto está principalmente motivado por la necesidad de explotar el gran número de aplicaciones identificadas en esta región frecuencial por un gran número de usuarios, incluyendo a usuarios no científicos. El enfoque fotónico empleado para estos propósitos ofrece importantes y exclusivas ventajas sobre otras alternativas existentes, que tienen como principal representante a la tecnología electrónica, especialmente en términos de rango de frecuencia de funcionamiento, posibilidad de distribución fotónica con fibras ópticas, peso, e inmunidad electromagnética. No obstante, las técnicas fotónicas tradicionalmente han ofrecido peores prestaciones en términos de ruido de fase, sintonía y rango dinámico (en generación) y ratio de conversión (en detección) con respecto a la tecnología electrónica de THz en el estado del arte. El trabajo realizado en esta tesis se centra en el diseño, desarrollo y validación de nuevas arquitecturas y componentes fotónicos tanto para generación como detección de ondas de sub-THz y THz que permitan solucionar las desventajas de las técnicas ópticas manteniendo todas sus ventajas. En esta tesis, varios sistemas de generación de sub-THz y THz han sido desarrollados utilizando arquitecturas Difference Frequency Generation (DFG) en las que la fuente DFG es proveída por un Optical Frequency Comb Generator (OFCG) y selección de modos ópticos. Diferentes dispositivos y técnicas son investigados para cada parte del sistema hasta conseguir un sintetizador de altas prestaciones. Passively Mode-Locked Laser Diodes (PMMLDs) son inicialmente evaluados como OFCG integrados. Un diseño mejorado del OFCG es conseguido mediante el uso de un esquema basado en un láser Discrete Mode (DM) bajo régimen Gain Switching (GS) y expansión del ancho de banda óptico mediante el uso de un modulador de fase Electro-Óptico (EO). Como estrategia de selección de modos ópticos, tanto filtrado óptico altamente selectivo como Optical Injection Locking (OIL) son usados y evaluados. Un fotodiodo comercial de ancho de banda 50 GHz y un fotomezclador de THz de superred n-i-pn-i-p son empleados. El sistema de generación final que se presenta en esta tesis consiste en un OFCG basado en GS, OIL como técnica de selección de modos ópticos y un fotomezclador de THz de superred n-i-pn-i-p. Este sintetizador ofrece un rango de funcionamiento de 60 a 140 GHz, directamente escalable a un rango entre 10 GHz y valores más allá de un THz. Sintonía cuasi-continua es ofrecida en todo el rango de frecuencia de operación, con una resolución en frecuencia de 0.1 Hz a 100 GHz que puede ser directamente escalable a 0.01 Hz a 100 GHz y 0.1 Hz a 1 THz. El ancho de línea a 3-dB de la señal a 120 GHz es menor de 10 Hz, solo limitada por la instrumentación de medida. El sistema ofrece una excelente estabilidad en potencia y frecuencia, con desviaciones sobre una hora de operación de 1.5 dB y 5 Hz, respectivamente. Estos valores también están limitados por la precisión e incertidumbre de la instrumentación de medida. Las prestaciones conseguidas por este sintetizador fotónico de sub-THz y THz para la mayoría de figuras de mérito, igualan o superan aquellas de las mejores soluciones comerciales electrónicas en el estado del arte, y supera algunas de estas características en más de un millón de veces en el caso de soluciones fotónicas comerciales en el estado del arte. La parte de detección de esta tesis explora el uso de arquitecturas fotónicas basadas en receptores EO heterodinos y los componentes clave que forman estas arquitecturas: Oscilador Local (OL) fotónico y mezcladores EO. Los primeros resultados son desarrollados en el entorno de microondas (<15 GHz) usando un amplificador de semiconductor óptico ultra no lineal (XN-SOA) como mezclador EO y un OL fotónico basado en GS. Se demuestra como este OL basado en GS ofrece una mejora significativa de las prestaciones del receptor con respecto al uso de OL fotónicos tradicionales basados en modulación lineal. Además, esta arquitectura de detección es validada en una aplicación real (imaging array fotónico), ofreciendo escalabilidad, flexibilidad y ratios de conversión razonables. Tras esto, un receptor EO heterodino es demostrado hasta frecuencias de 110 GHz. El OL fotónico empleado es el sintetizador de altas prestaciones presentado en esta tesis, mientras que el mezclador EO es un nuevo detector de THz: el np-i-pn cuasi-balístico. La primera muestra fabricada de estos nuevos dispositivos, especialmente diseñados y optimizados para detección homodina y heterodina, es empleada. El receptor EO heterodino resultante ofrece ratios de conversión de -75 dB. Este dispositivo es capaz de trabajar sin alimentación, lo que unido a la distribución fotónica del OL, ofrece un gran potencial para detección remota de ondas de sub-THz y THz. En resumen, las nuevas arquitecturas y dispositivos fotónicos presentados en esta tesis son capaces de ofrecer prestaciones en el estado del arte para generación de ondas de sub-THz y THz. En el caso de detectores EO heterodinos en frecuencias de sub-THz y THz, las técnicas fotónicas están mejorando sus prestaciones significativamente y están cada vez más cerca de ofrecer una alternativa a detectores electrónicos en el estado del arte

Wireless Terahertz Communications: Optoelectronic Devices and Signal Processing

Novel THz device concepts and signal processing schemes are introduced and experimentally confirmed. Record-high data rates are achieved with a simple envelope detector at the receiver. Moreover, a THz communication system using an optoelectronic receiver and a photonic local oscillator is shown for the first time, and a new class of devices for THz transmitters and receivers is investigated which enables a monolithic co-integration of THz components with advanced silicon photonic circuits

Communication satellite technology: State of the art and development opportunities

Opportunities in communication satellite technology are identified and defined. Factors that tend to limit the ready availability of satellite communication to an increasingly wide group of users are evaluated. Current primary limitations on this wide utilization are the availability of frequency and/or synchronous equatorial satellite positions and the cost of individual user Earth terminals. The former could be ameliorated through the reuse of frequencies, the use of higher frequency bands, and the reduction of antenna side lobes. The latter limitation requires innovative hardware, design, careful system design, and large scale production

Investigation of Millimetre Wave Generation by stimulated Brillouin scattering for Radio Over Fibre Applications

The rising demand for greater bandwidth and increased flexibility in modern telecommunication systems has lead to increased research activities in the field of Millimetre Wave-Photonics. The combination of an optical access network and the radio propagation of high data-rate signals provides a solution to meet these demands. Such structures are also known as Radio Over Fibre Systems. They implement the optical Millimetre Wave generation in a central station and the transmission of radio waves via a remote antenna unit to the radio cell. The expected data rate is very high, due to the fact that both the optical and the radio-link provide a large transmission bandwidth. This dissertation concerns the investigation of a new and simple method for the flexible generation of Millimetre Waves for application in Radio Over Fibre systems. The method is based on the heterodyne detection of two optical waves in a photo detector. By externally amplitude modulating the optical wave, different sidebands are generated. Two of these sidebands are selected and amplified by the non-linear effect of stimulated Brillouin scattering. As a gain medium, a standard single mode fibre is used. According to the theoretical investigation, very good carrier performances are possible with this method, and a computer simulation shows little degradation in the signals during their propagation in the system. The measured results are in strong agreement with the theoretical analysis. Experimental results show that the system can be fully utilised as a Radio Over Fibre system. The thesis is divided into five main parts: Introduction – Theory – Simulation – Experiment – Conclusion. In the Introduction, an overview of the current methods of Millimetre Wave Generation, Radio Over Fibre and the nonlinear effects of Brillouin scattering is given. In the theoretical section, a differential equation system which mathematically describes the system is derived and also solved numerically. With a proof of the concept set-up, the simulated results are compared with the experimental data. In the last section the work is conclude and future tasks are discus

Small business innovation research. Abstracts of completed 1987 phase 1 projects

Non-proprietary summaries of Phase 1 Small Business Innovation Research (SBIR) projects supported by NASA in the 1987 program year are given. Work in the areas of aeronautical propulsion, aerodynamics, acoustics, aircraft systems, materials and structures, teleoperators and robotics, computer sciences, information systems, spacecraft systems, spacecraft power supplies, spacecraft propulsion, bioastronautics, satellite communication, and space processing are covered

Bibliography of Lewis Research Center technical publications announced in 1987

This compilation of abstracts describes and indexes the technical reporting that resulted from the scientific and engineering work performed and managed by the Lewis Research Center in 1987. All the publications were announced in the 1987 issues of STAR (Scientific and Technical Aerospace Reports) and/or IAA (International Aerospace Abstracts). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses

Dynamics of resonant tunneling diode optoelectronic oscillators

Tese de dout., Física, Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2012The nonlinear dynamics of optoelectronic integrated circuit (OEIC) oscillators comprising semiconductor resonant tunneling diode (RTD) nanoelectronic quantum devices has been investigated. The RTD devices used in this study oscillate in the microwave band frequency due to the negative di erential conductance (NDC) of their nonlinear current voltage characteristics, which is preserved in the optoelectronic circuit. The aim was to study RTD circuits incorporating laser diodes and photo-detectors to obtain novel dynamical operation regimes in both electrical and optical domains taking advantage of RTD's NDC characteristic. Experimental implementation and characterization of RTD-OEICs was realized in parallel with the development of computational numerical models. The numerical models were based on ordinary and delay di erential equations consisting of a Li enard's RTD oscillator and laser diode single mode rate equations that allowed the analysis of the dynamics of RTD-OEICs. In this work, several regimes of operation are demonstrated, both experimentally and numerically, including generation of voltage controlled microwave oscillations and synchronization to optical and electrical external signals providing stable and low phase noise output signals, and generation of complex oscillations that are characteristic of high-dimensional chaos. Optoelectronic integrated circuits using RTD oscillators are interesting alternatives for more e cient synchronization, generation of stable and low phase noise microwave signals, electrical/optical conversion, and for new ways of optoelectronic chaos generation. This can lead to simpli cation of communication systems by boosting circuits speed while reducing the power and number of components. The applications of RTD-OEICs include operation as optoelectronic voltage controlled oscillators in clock recovery circuit systems, in wireless-photonics communication systems, or in secure communication systems using chaotic waveforms