High frequency operation of an integrated electro-absorption modulator onto a vertical-cavity surface-emitting laser

We present in this paper the vertical integration of an electro-absorption modulator (EAM) onto a vertical-cavity surface-emitting laser (VCSEL). We discuss the design, fabrication, and measured characteristics of the combined VCSEL and EAM. We previously demonstrated a standalone EAM with an optical bandwidth around 30 GHz. In this paper we present for the first time an optical bandwidth of 30 GHz for an EAM integrated onto a VCSEL. This device exhibits single-mode operation and a very low chirp, below 0.1 nm, even with a modulation depth of 70% which makes this device very competitive for high-speed communications in data centers

An Original SiGe Active Differential Output Power Splitter for Millimetre-wave Applications

This paper deals with an original design of an active power splitter featuring a differential output presenting a greatly enhanced even mode rejection.The proposed circuit consists in two cascaded common emitter and common collector differential pairs.For achieving the best performance,it is shown that each of these two differential pairs requires a specific common node to ground impedance that is discussed.The circuit has been implemented on a 0.25 µm SiGe BiCMOS process and exhibits anticipated phase and amplitude broadband unbalance less than 6.5 ° and 0.6 dB respectively all over the 6 -27 GHz frequency range.At 20 GHz,a common mode rejection ratio better than 43 dB is predicted,i.e.a maximum 0.12 dB /0.35 ° output signal unbalance

Optimisation de structures différentielles en technologie SiGe pour applications en bande millimétrique. Application à la conception d'un mélangeur doublement équilibré en bande K

Present work contributes to BiCMOS SiGe monolithic technology evaluation for future high-performance millimetre-wave telecommunications applications. For theses applications, balanced circuit architectures are very attractive according to their low noise susceptibility and their EMI radiation immunity. However, as frequency is increased, passive devices losses raise and classical differential amplifier topologies cannot achieve sufficiently well balanced operation. Thus, our main purpose is to propose innovative differential topologies suitable for millimetre-wave high-performance balanced circuits. Firstly, the evaluation of several interconnection technologies (microstrip, coplanar waveguide and coplanar strips) integrated on silicon substrate is presented. An inductor library then is designed for K and Ka frequency band operation. Enhanced performance inductors are issued from the analysis of losses mechanisms. A second part addresses the performance optimization of differential circuits for future applications in the 20-40 GHz frequency range. Firstly, we demonstrate that classical approaches for differential pair design lead to poor balanced behaviour in the millimetre-wave frequency band, because of intrinsic transistor characteristics. Original differential pair topologies are then proposed to overcome these drawbacks. These structures are then applied for the design of a 20 GHz active balun. Finally, a double balanced frequency converter from 20 GHz to 1 GHz is designed. The whole chip integrates the mixing cell and the three couplers. The characterization of this circuit demonstrates the usefulness of our choice for interconnections and confirms the great interest of developed original differential structures.Cette thèse apporte une contribution à l'évaluation des potentialités de filières SiGe de type BiCMOS pour les futures applications de télécommunications en bande millimétrique. Dans ce cadre, les topologies équilibrées ou différentielles sont très attrayantes, en raison de leur bonne immunité aux perturbations électriques et électromagnétiques. La montée en fréquence des applications hyperfréquences sur silicium s'accompagne de nouvelles difficultés. Les pertes introduites par les éléments passifs augmentent et les performances des structures différentielles classiques chutent très rapidement. Il est alors nécessaire d'exploiter d'autres techniques et de rechercher des topologies innovantes permettant la réalisation de fonctions équilibrées performantes. Une première partie est consacrée à l'évaluation des potentialités des différentes technologies d'interconnexions (microruban, guides coplanaires et lignes à rubans coplanaires) exploitables pour la conception de circuits monolithiques sur silicium. Dans un second temps, une bibliothèque d'inductances optimisées pour une utilisation en bande K et Ka est constituée. Les mécanismes physiques à l'origine des pertes dans ce type d'élément sont détaillés afin de dégager les solutions permettant d'améliorer leurs performances. Une deuxième partie traite de l'optimisation des performances des circuits différentiels pour les futures applications dans la gamme 20-40 GHz. Dans un premier temps, nous détaillons les caractéristiques hautes fréquences du transistor qui pénalisent le fonctionnement d'une structure différentielle classique. Des topologies de structures différentielles originales permettant de résoudre ce problème sont ensuite proposées. Ces structures sont appliquées à la conception d'un diviseur de puissance actif 180° original, optimisé pour une fréquence centrale de fonctionnement de 20 GHz. Enfin, un convertisseur de fréquences 20 GHz vers 1 GHz a été conçu et réalisé. Celui-ci intègre, outre le mélangeur, le s trois coupleurs actifs 180° nécessaires à la génération / recombinaison des signaux différentiels utiles au mélangeur. La caractérisation de ce convertisseur de fréquences démontre la pertinence des configurations choisies pour les interconnexions ainsi que le grand intérêt des structures différentielles originales mises en Suvre

Contribution à l’intégration des circuits micro-ondes et millimétriques pour les télécommunications

The work presented in this document deals with the integration of microwave and millimeter-wave circuits. It follows the global trend towards improvedperformances, miniaturized, low-power and cost-effective circuits. Our research activity includes both the integration of active circuits as well as passive components.The first given example proposes some solutions aimed for noise performance optimization of integrated RF power amplifiers whose non-linear operation translates the LF noise sources up to microwave frequencies.We then propose to use the passive mixer based on MOS transistors as a possible candidate for future flexible and reconfigurable radio architectures. The optimizations performed at the device level as well as circuit topology significantly push the maximum operating frequencies up to V and W bands through the implementation of sampling and sub-sampling techniques, which also significantly reduce mixer’s conversion losses.Finally, since the beginning of the microelectronic industry, the back-end-of-line is processed essentially in two dimensions, by stacking metal layers. We are developing an original approach that seeks to provide an additional degree of freedom by allowing the metalization of the sidewalls of a pillar of resin. This innovation, which has been patented, enables the fabrication of passive devices in three dimensions (3D), such as solenoids and RF transformers, for a very low cost. The successive improvements achieved in the fabrication process have led to extremely compact devices with performances that are currently at the level of the state of the art.Les travaux présentés dans cette habilitation traitent de l’intégration des circuits micro-ondes et millimétriques. Ils s’inscrivent dans une tendance mondiale dont les enjeux principaux sont l’amélioration des performances, la miniaturisation, la baisse de la consommation électrique des circuits ainsi que la maîtrise des coûts. Notre activité de recherche porte donc tout naturellement à la fois sur l’intégration des circuits actifs et des composants passifs.Le premier exemple évoqué propose quelques pistes de travail visant à optimiser les performances en bruit des amplificateurs de puissance intégrés dont le fonctionnement non-linéaire tend à transposer les sources de bruit BF vers les fréquences micro-ondes.Nous proposons ensuite d’employer le mélangeur passif à transistors MOS pour répondre aux besoins de plus en plus forts qui s’expriment en direction des architectures radio flexibles et reconfigurables. Les optimisations effectuées au niveau de la géométrie du composant et de la topologie du circuit repoussent significativement les fréquences limites de fonctionnement (bandes V et W) grâce à la mise en œuvre de techniques d’échantillonnage et de sous-échantillonnage qui réduisent également les pertes de conversions.Enfin, la microélectronique fonctionne essentiellement à deux dimensions depuis son apparition en procédant à un empilement de couches métalliques. Depuis quelque années, nous étudions une approche originale qui vise à dégager un degré de liberté supplémentaire en permettant la métallisation des flancs d’un pilier de résine. Cette innovation, qui a été brevetée, autorise la fabrication de composants passifs en trois dimensions (3D), tels que des solénoïdes et des transformateurs RF, pour un coût très faible. Les améliorations successives du procédé ont permis d’aboutir à des composants extrêmement compacts avec des performances qui se situent actuellement au niveau de l’état de l’art

Optimisation de structures différentielles en technologie SIGE pour applications en bande millimétrique (application à la conception d'un mélangeur doublement équilibré en bande K)

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

NMOS Device Optimization for the Design of a W-band Double-Balanced Resistive Mixer

Lettre pour IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS, acceptée pour publication le 11 juin 2014.International audienceThis letter describes the implementation of NMOS devices in a double-balanced resistive mixer whose operating frequency reaches device's cut-off frequency. Conversion gain, linearity and required LO power are analyzed regarding NMOS device geometry. This work is done using simple analytic formulas and validated by electrical simulations led on a ring mixer. As a result, a down-converter is designed using a 0.13 μm BiCMOS SiGe process. The circuit includes three surrounding amplifiers at RF, LO and IF terminals. Measurements indicate a conversion gain of 14.5 dB at 76.8 GHz, an output-referred 1dB compression point of −10 dBm and a DSB noise figure of 6.3 dB suggesting the interest of NMOS-based double-balanced passive mixers at such high frequencies

Conception et intégration "above IC" d'inductances à fort coefficient de surtension pour applications de puissance RF

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Evolution Trends and Paradigms of Low Noise Frequency Synthesis and Signal Conversion Using Silicon Technologies

International audienceSilicon technologies for HF applications have been proven for more than two decades, and technologies have greatly evolved. Whether CMOS or BiCMOS technologies, the unique combination of radio frequency, baseband, and digital functions allow a very high level of integration. While it is possible to achieve fully integrated transceivers, the major advantages of these silicon technologies lie mainly in their unparalleled performance in the field of frequency synthesis and frequency conversion. We propose in this paper a review of the major results obtained on these RF components since the beginning of the 2000s, also considering the impact of the technology node. The back-end of line (BEOL) process on which depends the quality of microwave monolithic integrated circuits (MMICs) is briefly presented in the introductory part. If circuit performances are tightly bound to the active devices (i.e., the heterojunction bipolar transistor SiGe HBT or CMOS transistor), passive elements (i.e., quality factor of inductors and varactors, losses of transmission, or interconnection lines) as well as the definition of the substrate also play a major role. The core of the article is oriented toward the noise of synthesized signals and frequency conversion. Frequency synthesis is presented through the analog design of a voltage-controlled oscillator (VCO) or through the direct digital frequency synthesis (DDFS), for which respective figures of merit are presented and discussed in a second section. The spectral purity of the oscillators being decisive in the definition of the throughput of a link is approached through the comparison of different figures of merit (FoM) for a set of circuits achievements over the selected period. If the realization of free oscillators is closely bound to the phase-locked loop (PLL)-type control loop for VCOs, the DDFS solution provides more direct and more flexible alternative at first sight. Therefore, these two solutions are analyzed collectively. Finally, the oscillator integrated in the transmitter or receiver supplies the needed LO (local oscillator) power to the frequency mixer in the frequency conversion module: henceforth, the third part of this study focuses on high-frequency mixer realizations. We thus consider this LO power in some advanced figure of merit mentioned in the second section. The design trade-off of the mixer is presented in an approach combining LO (conversion gain, channel isolation, and phase noise) and RF (HF noise figure and channel isolation) constraints. The final section provides a summary of the results and trends mentioned in the paper

Low Cost SU8 Based Above IC Process for High-Q RF Power Inductors Integration

International audienceThis paper presents a new process for integration of high-Q RF power inductors above low resistivity silicon substrates. The process uses the SU8 resin as a dielectric layer. The aim of using the SU8 is to form thick dielectric layer that can enhance the performance of the inductors. The flexibility of the process enables the possibility to realize complex shaped planar inductors with various dielectric and metal thicknesses to meet the requirements of the application. Q values of 55 at 5GHz has been demonstrated for an inductance value of 0.8nH using a 60 µm thick SU8 layer and 30 µm thick copper ribbons

A Low-Loss 77 GHz Sub-Sampling Passive Mixer Integrated in a 28-nm CMOS Radar Receiver

International audienceThis paper demonstrates that using sub-sampling mixer topology can be the right choice to implement a millimeter-wave (mmW) receiver. In a 77 GHz radar receiver, it allows to reduce the burden of a 77 GHz LO distribution chain, in term of area and consumption, while preserving RF performances. Demonstration is done from two topologies of ×3 sub-sampling mixers implemented in 28-nm FD-SOI CMOS technology. The best proposed passive mixer exhibits a-2.1 dB conversion gain (Gcv), a 1dB input-referred compression power (ICP1dB) of +3.5 dBm, and a 16.8 dB Single Side Band Noise Figure (NFSSB). The mixer LO signal shaping consumption is 32 mW on a 1.2 V supply while the passive mixer core does not require any DC power