A5045940123- Physics of Superconductivity and Magnetism
- Advanced Electrical Measurement Techniques
- Quantum and electron transport phenomena
- Magneto-Optical Properties and Applications
- Advancements in Semiconductor Devices and Circuit Design
- Superconducting and THz Device Technology
- Analog and Mixed-Signal Circuit Design
- Magnetic properties of thin films
- Superconducting Materials and Applications
- Magnetic Field Sensors Techniques
- Calibration and Measurement Techniques
- Quantum Computing Algorithms and Architecture
- Surface and Thin Film Phenomena
- Semiconductor Quantum Structures and Devices
- Power Quality and Harmonics
- Semiconductor materials and devices
- Radio Frequency Integrated Circuit Design
- Scientific Measurement and Uncertainty Evaluation
- Advancements in PLL and VCO Technologies
- Silicon Carbide Semiconductor Technologies
- Quantum Information and Cryptography
- Mechanical and Optical Resonators
- Terahertz technology and applications
- Parallel Computing and Optimization Techniques
- Spectroscopy and Laser Applications
Shanghai Institute of Microsystem and Information Technology
2021-2023
Chinese Academy of Sciences
2023
National Institute of Advanced Industrial Science and Technology
2010-2019
KDDI (Japan)
2008
Japan Advanced Institute of Science and Technology
2007
Nagoya Institute of Technology
2004
Electrotechnical Institute
2002
Nagoya University
1993
We propose a prime factorizer operated in framework of quantum annealing (QA). The idea is inverse operation multiplier implemented with QA-based Boolean logic circuits. designed the QA machine on an application-specific-annealing-computing architecture which efficiently increases available hardware budgets at cost restricted functionality. invertible gates consisting superconducting flux qubits was confirmed by circuit simulation classical noise sources. circuits were and fabricated using...
We present characteristics of overdamped Josephson junctions consisting Nb/AlOx/Al/ AlOx/Nb structures. The were fabricated using a well-developed Nb/AlOx/Nb-junction technology and showed well-defined at 4.2 K. characteristic voltage Vc [the product the critical current Ic effective normal resistance Rn(eff)] junctions, which determines high-frequency performance junction, was in range 0.1–0.5 mV, density Jc 102–104 A/cm2. Maximum-to-minimum variations over wafer ±4% for with Vc=0.15 mV...
The specific capacitance Cs of Nb/AlOx/Nb Josephson tunnel junction has been measured by means the superconducting quantum interference device (SQUID) resonance technique. We have investigated junctions with critical current densities Jc in range 0.1–18 kA/cm2 and found that 1/Cs linearly depends on a logarithm Jc. This suggests barrier thickness is moderately uniform area increases continuously during growth. results also show increasing reduces time constants junction.
We have developed a cell library for superconducting large scale integrated (LSI) digital circuits based on Single Flux Quantum (SFQ) devices. The were designed 6-kA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> Nb/AlO <sub xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> /Nb junction process with 10 mask levels including one ground plane and two Nb wiring layers. initial design optimization of the circuit parameters achieved by...
Digital to analog converters based on the Josephson effect are promising for voltage standards, because they produce steps with ultimate precision and stability. In this paper, we describe a project develop D/A converter designed synthesizing sinusoidal waveform metrological accuracy. The is RSFQ (Rapid Single Flux Quantum) logic circuits, consists of frequency multiplier (FM), pulse distributor (PD), number multipliers (VMs). Each VM circuit, corresponding n-th bit digital code, multiplies...
We have demonstrated that a superconductor-insulator-superconductor (SIS) mixer pumped by photonic local oscillator (LO) covers the whole frequency range of 0.2–0.5THz. In bandwidth 74% center frequency, this single-band receiver exhibits noise temperature TRX⩽20hf∕kB, where h is Planck’s constant, f and kB Boltzmann’s constant. Resultant TRX almost equal to identical SIS three conventional frequency-multiplier-based LOs which share 0.2–0.5THz band. This technique will contribute simple,...
In order to establish a quantum ac voltage standard at NMIJ/AIST, we have developed Josephson arbitrary waveform synthesizer based on overdamped junction arrays (JJAs) using optoelectronics and liquid helium free compact cryocooler. We succeeded in the generation of sine waves 60 Hz 152.6 kHz. To verify performance system, two different types JJAs with characteristic frequencies been developed. An application quantized noise source for Johnson thermometry is also discussed, experimental results.
We have been developing a new implementation of quantum voltage noise source (QVNS), an integrated QVNS (IQVNS), for Johnson thermometry (JNT) in thermal metrology. designed IQVNS chip based on rapid single flux (RSFQ) technology. A general formula the output power spectrum has derived by using Fourier analysis method, which shows that is calculable with sufficiently small errors practical JNT measurements.
The design and operation of a 9 bit superconductive single‐flux‐quantum (SFQ) digital‐to‐analogue converter (DAC) are presented. DAC comprises variable SFQ pulse number multiplier 100‐fold voltage multiplier. An pulse‐frequency modulation technique is employed for coding the analogue output voltage. fabricated using an Nb Josephson integration technology. Its waveform, amplitude which up to 2.54 m V pp , controlled by digital input signals from room‐temperature data generator.
We present a Johnson noise thermometry (JNT) system based on an integrated quantum voltage source (IQVNS) that has been fully implemented using superconducting circuit technology. To enable precise measurement of Boltzmann's constant, IQVNS chip was designed to produce intrinsically calculable pseudo-white calibrate the JNT system. On-chip real-time generation pseudo-random codes via simple circuits produced pseudo-voltage with harmonic tone interval less than 1 Hz, which one order magnitude...
We have developed a 6-kA/cm superconducting integrated circuit fabrication process toward large-scale single flux quantum digital circuits. To evaluate the reliability and controllability, set of control monitors (PCMs) for monitoring design parameters was designed tested. Fabrication parameters, example, film thicknesses etched depths layers, were measured by testing specific patterns during fabrication. Design such as critical current density J <sub...
Dual-rail logic circuit elements based on rapid single-flux-quantum (RSFQ) technology have been designed and simulated. The proposed circuits can operate asynchronously, since dual-rail data include timing information in themselves. Therefore scheme has a possibility of solving some problems RSFQ with flow clocking, which would become more serious as operating speed complexity the increase. Implementation AND XOR cells is described. A transfer-ring from flow-clocked to parallel also...
We have developed a fabrication technology for the development of large-scale superconducting integrated circuits with Nb-based Josephson junctions. The standard process 10 mask levels uses four metal layers including 3 Nb and Mo resistor layer. influence deposition parameters on film stress, electrical properties, surface roughness were studied systematically. High quality Nb, Al, Mo, SiO2 films successfully deposited subsequent circuits. circuit started resistors target sheet resistance...
Flux penetrations into three-dimensional Nb superconducting strip arrays, where two layers of arrays are stacked by shifting a half period, studied using magneto-optical imaging method. avalanches observed when the overlap between top and bottom is large even if width each well below threshold value. In addition, anomalous linear perpendicular to in shifted array very thickness superconductor greater than penetration depth. We discuss possible origins for flux avalanches, including ones,...
Abstract Rapid-single-flux-quantum digital-to-analogue converters (RSFQ-DACs) are now under development for ac voltage standard applications. The multiplier (VM), which precisely amplifies the input voltage, is a key component RSFQ-DACs. Because amount of bias current conventional VM increases in proportion to its multiplication factor, we have been looking device operated on different principle. In this paper, report our design 1000-fold comprising double flux quantum amplifiers (DFQAs)...
We propose a prime factoring machine operated in frame work of quantum annealing (QA). The idea is inverse operation quantum-mechanically reversible multiplier implemented with QA-based Boolean logic circuits. designed the QA on an application-specific-annealing-computing architecture which efficiently increases available hardware budgets at cost restricted functionality. circuits are to be and fabricated by using superconducting integrated circuit technology. three-dimensional packaging...
Synthesis of sinusoidal voltage waveform is a unique application in single-flux-quantum (SFQ) digital electronics. In this paper, the authors present synthesizer based on SFQ pulse-frequency modulation. It comprises variable pulse-number-multiplier (PNM) and code generator (CG) integrated same chip. The output determined by multiplication factor variable-PNM, which controlled from CG instead room-temperature variable-PNM realizes 5-bit resolution with factors between 33 64. generates codes...
We evaluate the input–output characteristics of a 1000-fold voltage multiplier designed for single-flux-quantum (SFQ) digital-to-analog converters. The multiplication is based on double-flux-quantum amplifier (DFQA) that was originally proposed by Herr in 2005. have and fabricated 999-stage DFQA using Nb/AlOx/Nb integration technology. In experiments, we used two methods feeding input SFQ pulse train. one an overbiasing method, i.e., train generated at overbiased junction. A with errors less...
We present the design improvement of an integrated quantum voltage noise source (IQVNS) aimed at low-cost user-friendly Johnson thermometers with high accuracy. A problem in our previous IQVNS was mainly associated lax synchronization low- and high-frequency clock signals, making whole system complicated less robust. have employed on-chip generation low-frequency clocks by downconverting a reference so that operates single clock. Counterflow-clocking architecture has been introduced both...
We propose a novel system of 3-D scanning superconducting quantum interference device (SQUID) microscope with high sensitivity for magnetic fields and spatial resolution. Our SQUID consists an XYZ piezodriven scanner controlling the position pickup coils, three sensors, three-channel electronics at room temperature. Three sensors are fabricated in same chip, each has coil directions, respectively. The SQUIDs used our reproducibly using Nb multilayer process fabrication center named CRAVITY....