Harnessing high-dimensional hyperentanglement through a biphoton frequency comb

Quantum entanglement is a fundamental resource for secure information processing and communications, where hyperentanglement or high-dimensional entanglement has been separately proposed towards high data capacity and error resilience. The continuous-variable nature of the energy-time entanglement makes it an ideal candidate for efficient high-dimensional coding with minimal limitations. Here we demonstrate the first simultaneous high-dimensional hyperentanglement using a biphoton frequency comb to harness the full potential in both energy and time domain. The long-postulated Hong-Ou-Mandel quantum revival is exhibited, with up to 19 time-bins, 96.5% visibilities. We further witness the high-dimensional energy-time entanglement through Franson revivals, which is observed periodically at integer time-bins, with 97.8% visibility. This qudit state is observed to simultaneously violate the generalized Bell inequality by up to 10.95 deviations while observing recurrent Clauser-Horne-Shimony-Holt S-parameters up to 2.76. Our biphoton frequency comb provides a platform in photon-efficient quantum communications towards the ultimate channel capacity through energy-time-polarization high-dimensional encoding

저 잡음 디지털 위상동기루프의 합성

학위논문 (박사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2014. 2. 정덕균.As a device scaling proceeds, Charge Pump PLL has been confronted by many design challenges. Especially, a leakage current in loop filter and reduced dynamic range due to a lower operating voltage make it difficult to adopt a conventional analog PLL architecture for a highly scaled technology. To solve these issues, All Digital PLL (ADPLL) has been widely studied recently. ADPLL mitigates a filter leakage and a reduced dynamic range issues by replacing the analog circuits with digital ones. However, it is still difficult to get a low jitter under low supply voltage. In this thesis, we propose a dual loop architecture to achieve a low jitter even with a low supply voltage. And bottom-up based multi-step TDC and DCO are proposed to meet both fine resolution and wide operation range. In the aspect of design methodology, ADPLL has relied on a full custom design method although ADPLL is fully described in HDL (Hardware Description Language). We propose a new cell based layout technique to automatically synthesize the whole circuit and layout. The test chip has no linearity degradation although it is fully synthesized using a commercially available auto P&R tool. We has implemented an all digital pixel clock generator using the proposed dual loop architecture and the cell based layout technique. The entire circuit is automatically synthesized using 28nm CMOS technology. And s-domain linear model is utilized to optimize the jitter of the dual-loop PLL. Test chip occupies 0.032mm2, and achieves a 15ps_rms integrated jitter although it has extremely low input reference clock of 100 kHz. The whole circuit operates at 1.0V and consumes only 3.1mW.Abstract i Lists of Figures vii Lists of Tables xiii 1. Introduction 1 1.1 Thesis Motivation and Organization 1 1.1.1 Motivation 1 1.1.2 Thesis Organization 2 1.2 PLL Design Issues in Scaled CMOS Technology 3 1.2.1 Low Supply Voltage 4 1.2.2 High Leakage Current 6 1.2.3 Device Reliability: NBTI, HCI, TDDB, EM 8 1.2.4 Mismatch due to Proximity Effects: WPE, STI 11 1.3 Overview of Clock Synthesizers 14 1.3.1 Dual Voltage Charge Pump PLL 14 1.3.2 DLL Based Edge Combining Clock Multiplier 16 1.3.3 Recirculation DLL 17 1.3.4 Reference Injected PLL 18 1.3.5 All Digital PLL 19 1.3.6 Flying Adder Clock Synthesizer 20 1.3.7 Dual Loop Hybrid PLL 21 1.3.8 Comparisons 23 2. Tutorial of ADPLL Design 25 2.1 Introduction 25 2.1.1 Motivation for a pure digital 25 2.1.2 Conversion to digital domain 26 2.2 Functional Blocks 26 2.2.1 TDC, and PFD/Charge Pump 26 2.2.2 Digital Loop Filter and Analog R/C Loop Filter 29 2.2.3 DCO and VCO 34 2.2.4 S-domain Model of the Whole Loop 34 2.2.5 ADPLL Loop Design Flow 36 2.3 S-domain Noise Model 41 2.3.1 Noise Transfer Functions 41 2.3.2 Quantization Noise due to Limited TDC Resolution 45 2.3.3 Quantization Noise due to Divider ΔΣ Noise 46 2.3.4 Quantization Noise due to Limited DCO Resolution 47 2.3.5 Quantization Noise due to DCO ΔΣ Dithering 48 2.3.6 Random Noise of DCO and Input Clock 50 2.3.7 Over-all Phase Noise 50 3. Synthesizable All Digital Pixel Clock PLL Design 53 3.1 Overview 53 3.1.1 Introduction of Pixel Clock PLL 53 3.1.1 Design Specifications 55 3.2 Proposed Architecture 60 3.2.1 All Digital Dual Loop PLL 60 3.2.2 2-step controlled TDC 61 3.2.3 3-step controlled DCO 64 3.2.4 Digital Loop Filter 76 3.3 S-domain Noise Model 78 3.4 Loop Parameter Optimization Based on the s-domain Model 85 3.5 RTL and Gate Level Circuit Design 88 3.5.1 Overview of the design flow 88 3.5.2 Behavioral Simulation and Gate level synthesis 89 3.5.1 Preventing a meta-stability 90 3.5.1 Reusable Coding Style 92 3.6 Layout Synthesis 94 3.6.1 Auto P&R 94 3.6.2 Design of Unit Cells 97 3.6.3 Linearity Degradation in Synthesized TDC 98 3.6.4 Linearity Degradation in Synthesized DCO 106 3.7 Experiment Results 109 3.7.1 DCO measurement 109 3.7.2 PLL measurement 113 3.8 Conclusions 117 A. Device Technology Scaling Trends 118 A.1. Motivation for Technology Scaling 118 A.2. Constant Field Scaling 120 A.3. Quasi Constant Voltage Scaling 123 A.4. Device Technology Trends in Real World 124 B. Spice Simulation Tip for a DCO 137 C. Phase Noise to Jitter Conversion 141 Bibliography 144 초록 151Docto

Low Power Analog to Digital Converters in Advanced CMOS Technology Nodes

The dissertation presents system and circuit solutions to improve the power efficiency and address high-speed design issues of ADCs in advanced CMOS technologies. For image sensor applications, a high-performance digitizer prototype based on column-parallel single-slope ADC (SS-ADC) topology for readout of a back-illuminated 3D-stacked CMOS image sensor is presented. To address the high power consumption issue in high-speed digital counters, a passing window (PW) based hybrid counter topology is proposed. To address the high column FPN under bright illumination conditions, a double auto-zeroing (AZ) scheme is proposed. The proposed techniques are experimentally verified in a prototype chip designed and fabricated in the TSMC 40 nm low-power CMOS process. The PW technique saves 52.8% of power consumption in the hybrid digital counters. Dark/bright column fixed pattern noise (FPN) of 0.0024%/0.028% is achieved employing the proposed double AZ technique for digital correlated double sampling (CDS). A single-column digitizer consumes total power of 66.8μW and occupies an area of 5.4 µm x 610 µm. For mobile/wireless receiver applications, this dissertation presents a low-power wide-bandwidth multistage noise-shaping (MASH) continuous-time delta-sigma modulator (CT-ΔΣM) employing finite impulse response (FIR) digital-to-analog converters (DACs) and encoder-embedded loop-unrolling (EELU) quantizers. The proposed MASH 1-1-1 topology is a cascade of three single-loop first-order CT-ΔΣM stages, each of which consists of an active-RC integrator, a current-steering DAC, and an EELU quantizer. An FIR filter in the main 1.5-bit DAC improves the modulator’s jitter sensitivity performance. FIR’s effect on the noise transfer function (NTF) of the modulator is compensated in the digital domain thanks to the MASH topology. Instead of employing a conventional analog direct feedback path, a 1.5-bit EELU quantizer based on multiplexing comparator outputs is proposed; this approach is suitable for highspeed operation together with power and area benefits. Fabricated in a 40-nm low-power CMOS technology, the modulator’s prototype achieves a 67.3 dB of signal-to-noise and distortion ratio (SNDR), 68 dB of signal-to-noise ratio (SNR), and 68.2 dB of dynamic range (DR) within 50.5 MHz of bandwidth (BW), while consuming 19 mW of total power (P). The proposed modulator features 161.5 dB of figure-of-merit (FOM), defined as FOM = SNDR + 10 log10 (BW/P)

Electronics for Sensors

The aim of this Special Issue is to explore new advanced solutions in electronic systems and interfaces to be employed in sensors, describing best practices, implementations, and applications. The selected papers in particular concern photomultiplier tubes (PMTs) and silicon photomultipliers (SiPMs) interfaces and applications, techniques for monitoring radiation levels, electronics for biomedical applications, design and applications of time-to-digital converters, interfaces for image sensors, and general-purpose theory and topologies for electronic interfaces

Strategies towards high performance (high-resolution/linearity) time-to-digital converters on field-programmable gate arrays

Time-correlated single-photon counting (TCSPC) technology has become popular in scientific research and industrial applications, such as high-energy physics, bio-sensing, non-invasion health monitoring, and 3D imaging. Because of the increasing demand for high-precision time measurements, time-to-digital converters (TDCs) have attracted attention since the 1970s. As a fully digital solution, TDCs are portable and have great potential for multichannel applications compared to bulky and expensive time-to-amplitude converters (TACs). A TDC can be implemented in ASIC and FPGA devices. Due to the low cost, flexibility, and short development cycle, FPGA-TDCs have become promising. Starting with a literature review, three original FPGA-TDCs with outstanding performance are introduced. The first design is the first efficient wave union (WU) based TDC implemented in Xilinx UltraScale (20 nm) FPGAs with a bubble-free sub-TDL structure. Combining with other existing methods, the resolution is further enhanced to 1.23 ps. The second TDC has been designed for LiDAR applications, especially in driver-less vehicles. Using the proposed new calibration method, the resolution is adjustable (50, 80, and 100 ps), and the linearity is exceptionally high (INL pk-pk and INL pk-pk are lower than 0.05 LSB). Meanwhile, a software tool has been open-sourced with a graphic user interface (GUI) to predict TDCs’ performance. In the third TDC, an onboard automatic calibration (AC) function has been realized by exploiting Xilinx ZYNQ SoC architectures. The test results show the robustness of the proposed method. Without the manual calibration, the AC function enables FPGA-TDCs to be applied in commercial products where mass production is required.Time-correlated single-photon counting (TCSPC) technology has become popular in scientific research and industrial applications, such as high-energy physics, bio-sensing, non-invasion health monitoring, and 3D imaging. Because of the increasing demand for high-precision time measurements, time-to-digital converters (TDCs) have attracted attention since the 1970s. As a fully digital solution, TDCs are portable and have great potential for multichannel applications compared to bulky and expensive time-to-amplitude converters (TACs). A TDC can be implemented in ASIC and FPGA devices. Due to the low cost, flexibility, and short development cycle, FPGA-TDCs have become promising. Starting with a literature review, three original FPGA-TDCs with outstanding performance are introduced. The first design is the first efficient wave union (WU) based TDC implemented in Xilinx UltraScale (20 nm) FPGAs with a bubble-free sub-TDL structure. Combining with other existing methods, the resolution is further enhanced to 1.23 ps. The second TDC has been designed for LiDAR applications, especially in driver-less vehicles. Using the proposed new calibration method, the resolution is adjustable (50, 80, and 100 ps), and the linearity is exceptionally high (INL pk-pk and INL pk-pk are lower than 0.05 LSB). Meanwhile, a software tool has been open-sourced with a graphic user interface (GUI) to predict TDCs’ performance. In the third TDC, an onboard automatic calibration (AC) function has been realized by exploiting Xilinx ZYNQ SoC architectures. The test results show the robustness of the proposed method. Without the manual calibration, the AC function enables FPGA-TDCs to be applied in commercial products where mass production is required

Design/cost tradeoff studies. Appendix A. Supporting analyses and tradeoffs, book 1. Earth Observatory Satellite system definition study (EOS)

A listing of the Earth Observatory Satellite (EOS) candidate missions is presented for use as a baseline in describing the EOS payloads. The missions are identified in terms of first, second, and third generation payloads. The specific applications of the EOS satellites are defined. The subjects considered are: (1) orbit analysis, (2) space shuttle interfaces, (3) thematic mapping subsystem, (4) high resolution pointable imager subsystem, (5) the data collection system, (6) the synthetic aperture radar, (7) the passive multichannel microwave radiometer, and (8) the wideband communications and handling equipment. Illustrations of the satellite and launch vehicle configurations are provided. Block diagrams of the electronic circuits are included

Electro-optic frequency combs and their applications in high-precision metrology and high-speed communications

Optische Frequenzkämme haben sich in den letzten Jahren zu einem vielseitigen Werkzeug im Bereich der Optik und Photonik entwickelt. Sie ermöglichen den Zugang zu einer Vielzahl von schmalbandigen Spektrallinien, die einen breiten Spektralbereich abdecken und gleichzeitig hochgenau definierte Frequenzen aufweisen. Dadurch wurden Experimente in vielfältigen Anwendungsgebieten ermöglicht, zum Beispiel in den Bereichen optischer Atomuhren, der Präzisionsspektroskopie, der Frequenzmesstechnik, der Distanzmesstechnik und der optischen Telekommunikation. Allerdings umfassen übliche Frequenzkammquellen und die jeweiligen Laboraufbauten typischerweise komplexe opto-elektronische und opto-mechanische Anordnungen, welche aufgrund von Baugröße und fehlender Robustheit gegenüber Umwelteinflüssen wie Temperatur bislang kaum Einzug in breitere industrielle Anwendungen gefunden haben. Diese Arbeit legt deshalb ein besonderes Augenmerk auf die praktische Nutzbarkeit von frequenzkamm-basierten Systemen in industriellen Anwendungen. Im Fokus stehen dabei Robustheit, Kompaktheit und flexible Anpassungsmöglichkeiten an die jeweilige Anwendung. Das bezieht sich sowohl auf die Frequenzkammquellen selbst, als auch auf die zugehörigen anwendungsspezifischen optischen Systeme, in welchen die Frequenzkämme genutzt werden. In der vorliegenden Arbeit wird das Potential elektro-optischer Frequenzkämme in der optischen Messtechnik sowie der optischen Kommunikationstechnik anhand ausgewählter experimenteller Demonstrationen untersucht. Als Mittel zur Realisierung miniaturisierter optischer Systeme mit einem Flächenbedarf von wenigen Quadratmillimetern wird die photonische Integration in Silizium verfolgt. Ein integriertes System zur Frequenzkamm-basierten Distanzmessung sowie integriert-optische Frequenzkammquellen werden demonstriert. Die Erzeugung von Frequenzkämmen durch Dauerstrichlaser in Kombination mit elektro-optischen Modulatoren ist dabei ein besonders vielversprechender Ansatz. Zwar werden dabei üblicherweise kleinere optische Bandbreiten erzielt als bei der weitverbreiteten Frequenzkammerzeugung durch modengekoppelte Ultrakurzpulslaser oder durch Kerr-Nichtlinearitäten, aber es bieten sich andere wertvolle Vorteile an. So erlaubt die elektro-optische Kammerzeugung beispielsweise eine nahezu freie Wahl der Mittenfrequenz durch Auswahl oder Einstellung des Dauerstrichlasers. Durch den Einsatz verschiedener Laser können sogar gleichzeitig mehrere Frequenzkämme unterschiedlicher Mittenfrequenz erzeugt werden, was sich in verschiedenen Anwendungen vorteilhaft ausnutzen lässt. Dies wird in dieser Arbeit anhand zweier Beispiele aus der optischen Messtechnik demonstriert, siehe Kapitel 3 und Kapitel 5. Der Kammlinienabstand ist bei elektro-optisch erzeugten Kämmen definiert durch die elektronisch erzeugte Modulationsfrequenz. Das bietet mehrere Vorteile: Der Linienabstand ist frei einstellbar, sehr stabil, und einfach rückführbar auf einen Frequenzstandard. Der Verzicht auf einen optischen Resonator macht die Kammquelle robust gegenüber Umwelteinflüssen wie z.B. Vibration. Zudem machen Fortschritte bei der Entwicklung von hochintegrierten optischen Modulatoren auf Silizium eine Umsetzung der Frequenzkammquellen in Siliziumphotonik möglich. Die erste derartige Komponente und deren Anwendung in der optischen Telekommunikation wird in Kapitel 6 vorgestellt. Photonische Integration in Silizium bietet außerdem das Potential, miniaturisierte optische Systeme mit vielfältiger Funktionalität zu realisieren. Solche Systeme zeichnen sich durch extrem kleinen Platzbedarf, Kompatibilität mit hochentwickelten und massentauglichen Fertigungstechniken aus der CMOS-(Complementary Metal-Oxide-Semiconductor)-Mikroelektronik und durch die Möglichkeit zur Kointegration elektronischer Schaltungen auf demselben Chip aus. Die hohe Integrationsdichte eröffnet die Perspektive, optische Systeme z.B. für Sensorik tief in industriellen Maschinen zu integrieren. Kapitel 1 gibt eine kurze Einführung in optische Frequenzkämme und deren vielfältige Anwendungen in Wissenschaft und Technik. Der Stand der Technik zu unterschiedlichen Ansätzen zur Frequenzkammerzeugung und deren jeweiligen Eigenschaften werden diskutiert, und es werden die Vorzüge der in dieser Arbeit verwendeten elektro-optischen Frequenzkämme erläutert. Des Weiteren wird die Integration photonischer Systeme und Bauelemente auf Silizium vorgestellt. Schließlich werden die sich ergebenden Vorteile bei der Anwendung in optischer Messtechnik und optischer Telekommunikation diskutiert. Kapitel 2 fasst die physikalischen Grundlagen der Arbeit zusammen. Die Funktionsprinzipien elektro-optischer Modulatoren werden beschrieben sowie deren Anwendung zur Erzeugung von Frequenzkämmen. Zusätzlich wird das Konzept sogenannter synthetischer Wellenlängen eingeführt, welches in der optischen Distanzmesstechnik Anwendung findet. Kapitel 3 beschreibt ein Prinzip zur Distanzmessung mittels zweier elektro-optischer Frequenzkämme zur kontaktlosen Vermessung technischer Objekte. Die Leistungsfähigkeit des Ansatzes wird durch eine Erfassung von ausgedehnten Oberflächenprofilen in Form von Punktwolken demonstriert, wobei eine verhältnismäßig kurze Messzeit von 9.1 µs pro Punkt ausreichend ist. Dabei wird der faseroptisch angebundene Sensorkopf von einer Koordinatenmessmaschine über die Oberfläche bewegt. Durch Temperaturschwankungen im faser-optischen Aufbau ausgelöste Messabweichungen werden durch die Messung mit Lasern unterschiedlicher Emissionsfrequenz kompensiert. Kapitel 4 beschreibt ein integriert-optisches System auf Silizium zur frequenzkamm-basierten Distanzmessung. Das System beinhaltet das zum Heterodynempfang genutzte Interferometer inklusive eines einstellbaren Leistungsteilers sowie der Photodetektoren. Der Platzbedarf aller Komponenten auf dem Siliziumchip beträgt 0.25 mm$^{2}$. Der Chip wird in dem in Kapitel 3 eingeführten Messverfahren eingesetzt, wobei Distanzmessungen mit Root-mean-square-Fehlern von 3.2 µm und 14 µs Erfassungszeit demonstriert werden. Kapitel 5 stellt ein Distanzmesssystem vor, bei welchem eine grobauflösende Phasenlaufzeitmessung mit großem Eindeutigkeitsbereich mit einer interferometrischen Distanzmessung mit synthetischen Wellenlängen zur Verfeinerung der Messgenauigkeit kombiniert wird. Die durch vier Laser erzeugten synthetischen Wellenlängen bzw. die Frequenzabstände der Laser werden zeitgleich zur Distanzmessung mittels eines auf elektro-optischer Modulation basierenden Verfahrens vermessen. Durch diese Referenzierung wird der Einsatz freilaufender Laser ohne Wellenlängenstabilisierung ermöglicht. Es werden Messraten von 300 Hz und Genauigkeiten im Mikrometerbereich erreicht. Kapitel 6 beschreibt die weltweit erste Demonstration elektro-optischer Frequenzkammquellen auf Silizium und die hierzu genutzte hybride Materialplattform aus Silizium und organischen Materialien (Silicon-Organic Hybrid, SOH). Spektral flache Frequenzkämme mit 7 Linien innerhalb von 2 dB und Linienabständen von 25 GHz und 40 GHz werden erzeugt. Die praktische Anwendbarkeit solcher Frequenzkämme wird durch eine Reihe von Datenübertragungexperimenten demonstriert. Die einzelnen Kammlinien dienen als Träger für Daten in einem Wellenlängenmultiplex-System, womit eine spektral effiziente Datenübertragung mit Datenraten von über 1 Tbit/s über Distanzen von bis zu 300 km demonstriert wird. Kapitel 7 fasst die Ergebnisse der vorliegenden Arbeit zusammen und gibt einen Ausblick auf die Möglichkeiten, die sich durch weiterentwickelte Kammquellen und fortschreitende Möglichkeiten in der photonischen Integration ergeben

MATLAB

A well-known statement says that the PID controller is the "bread and butter" of the control engineer. This is indeed true, from a scientific standpoint. However, nowadays, in the era of computer science, when the paper and pencil have been replaced by the keyboard and the display of computers, one may equally say that MATLAB is the "bread" in the above statement. MATLAB has became a de facto tool for the modern system engineer. This book is written for both engineering students, as well as for practicing engineers. The wide range of applications in which MATLAB is the working framework, shows that it is a powerful, comprehensive and easy-to-use environment for performing technical computations. The book includes various excellent applications in which MATLAB is employed: from pure algebraic computations to data acquisition in real-life experiments, from control strategies to image processing algorithms, from graphical user interface design for educational purposes to Simulink embedded systems

Advances in Optical Amplifiers

Optical amplifiers play a central role in all categories of fibre communications systems and networks. By compensating for the losses exerted by the transmission medium and the components through which the signals pass, they reduce the need for expensive and slow optical-electrical-optical conversion. The photonic gain media, which are normally based on glass- or semiconductor-based waveguides, can amplify many high speed wavelength division multiplexed channels simultaneously. Recent research has also concentrated on wavelength conversion, switching, demultiplexing in the time domain and other enhanced functions. Advances in Optical Amplifiers presents up to date results on amplifier performance, along with explanations of their relevance, from leading researchers in the field. Its chapters cover amplifiers based on rare earth doped fibres and waveguides, stimulated Raman scattering, nonlinear parametric processes and semiconductor media. Wavelength conversion and other enhanced signal processing functions are also considered in depth. This book is targeted at research, development and design engineers from teams in manufacturing industry, academia and telecommunications service operators

Realization of Integrated Coherent LiDAR

LiDAR (Light Detection and Ranging) captures high-definition real-time 3D images of the surrounding environment through active sensing with infrared lasers. It has unique advantages that can compensate the fundamental limitations in camera-based 3D imaging via vision algorithms or RADARs, which makes it an important sensing modality to guarantee robust autonomy in self-driving cars. However, high price tag of existing commercial LiDAR modules based on mechanical beam scanners and intensity-based detection scheme makes them unusable in the context of mass produced consumer products.The focus of thesis is on the integrated coherent LiDAR with optical phased array-based solid-state beam steering, which has great potential to dramatically bring down the cost of a LiDAR module. It begins with an overview of LiDAR implementation options and system requirements in the context of autonomous vehicles, which leads us to conclude that beam-steering coherent FMCW LiDAR in optical C-band is indeed the best implementation strategy to realize low-cost automotive LiDARs. Motivated by this observation, a quantitative framework for evaluating FMCW LiDAR performance is also introduced to predict the design that satisfies car-grade performance requirements. Then the thesis presents the silicon implementation results from our single-chip optical phased array and integrated coherent LiDAR prototype. Our implementations leverage the 3D heterogeneous integration platform, where custom silicon photonics and nanoscale CMOS fabricated at a 300 mm wafer facility are combined at the wafer-scale to minimize the unit cost without I/O density issues. After discussing remaining challenges and possible ways to enhance the operating range and system reliability, this thesis finally addresses the problem of fundamental trade-off between phase noise and wavelength tuning in FMCW laser source, and present circuit- and algorithm-level techniques to enable FMCW measurements beyond inherent laser coherence range limit