A5025954838- Physics of Superconductivity and Magnetism
- Quantum and electron transport phenomena
- Quantum Information and Cryptography
- Advanced Electrical Measurement Techniques
- Magnetic Field Sensors Techniques
- Mechanical and Optical Resonators
- Advancements in Semiconductor Devices and Circuit Design
- Magneto-Optical Properties and Applications
- Quantum optics and atomic interactions
- Surface and Thin Film Phenomena
- Radio Frequency Integrated Circuit Design
- Superconducting Materials and Applications
- Semiconductor Quantum Structures and Devices
- Photonic and Optical Devices
- Magnetic properties of thin films
- Atomic and Subatomic Physics Research
- Analog and Mixed-Signal Circuit Design
- Superconducting and THz Device Technology
- Magnetic confinement fusion research
- Superconductivity in MgB2 and Alloys
- Magnetic Properties and Applications
- Gyrotron and Vacuum Electronics Research
- Low-power high-performance VLSI design
- Semiconductor materials and devices
- Optical Network Technologies
Physikalisch-Technische Bundesanstalt
2006-2023
D-Wave Systems (Canada)
2008
Russian Academy of Sciences
1993-1999
Leibniz Institute of Photonic Technology
1999
Helmholtz Institute Jena
1999
Lomonosov Moscow State University
1994
Institute of Radio-Engineering and Electronics
1989-1993
New elements of the rapid single flux quantum (RSFQ) logic family have been designed, fabricated, and tested. All-Nb 14-layer 5 mu m technology using externally shunted tunnel junctions with j/sub c/=500 A/cm/sup 2/, I/sub c/R/sub s/=300 V, B/sub c/<or=1 has used. The T-flip-flop circuit demonstrated to operate +or-30% margins at clock frequencies below 50 GHz least +or-10% up 120 GHz. Operation input (DC/SFQ) output (SFQ/DC) converters +or-40% is also demonstrated.<<ETX>>
We report on the functionality of a Nb-based superconducting single flux quantum (SFQ) toggle flip-flop (TFF) circuit, comprising complementary superconductor–ferromagnet–superconductor (SFS) Josephson π-junction. The SFS junction was used as phase shifting element inserted in storage loop TFF. fabricated circuits demonstrated correct with operation parameter ranges ± 20%. application π-junctions makes SFQ very compact, may substantially improve their stability, and also be suitable for...
We develop a novel concept of Josephson traveling-wave parametric amplifier with three-wave mixing. The proposed consists microwave transmission line formed by serial array nonhysteretic one-junction SQUIDs. These SQUIDs are flux-biased such that the phase drops across junctions equal to 90°. This one-dimensional metamaterial possesses large quadratic nonlinearity and minimal cubic (Kerr-like) nonlinearity. property allows matching exponential power gain in wide frequency range....
We analyze the effect of circuit parameter variation on performance Josephson traveling-wave parametric amplifiers (JTWPAs). Specifically, JTWPA concept we investigate is using flux-biased nonhysteretic rf-SQUIDs in a transmission line configuration, which harnesses three-wave mixing (3WM) regime. Dispersion engineering enables phase-matching to achieve power gain <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math...
A new A/D converter which includes a comparator, and reversible binary counter with DC outputs has been designed, fabricated, tested. The comparator generates two trains of the single-flux-quantum (SFQ) pulses in response to increasing or decreasing input signal. are transferred through SFQ transmission lines adding diminishing inputs counter. realized by supplementing usual lines, splitters; confluence elements for sending diminished directly each bit. Nondestructive read-out contents is...
Quantized values of magnetic flux trapped in a superconducting loop enable new type passive phase shifting elements. These elements can be incorporated into digital Josephson circuits making their design compact. We have proven the functionality such shifters fabricated conventional Nb/Al trilayer technology. report on successful low speed operation rapid single quantum toggle flip-flop circuit with integrated pi-phase element.
The paper reports on recent developments in a new technology process LTS implementation to fabricate intrinsically shunted tunnel junctions. has been realized SINIS multilayer thin-film technology. In various test series, circuits containing large variety of single junctions and junction arrays different contact areas sizes were fabricated measured. By variation the oxidation parameters fabrication optimized for application integrated operating RSFQ impulse logic. parameter values critical...
This paper reports on the evaluation of effective suppression parameter effin double-barrier Josephson junctions realized in Nb-Al/Alx Oy /Al/Alx /Al-Nb SINIS technology. describes overall resistance current flow across interfaces within whole structure configuration and characterizes its IC RNproduct attainable. By comparison with theoretical descriptions tunnelling structures dirty-limit approximation, effhas been extracted from measured temperature dependence RNproduct. For a series...
All-aluminum Josephson junctions with high-transparency barriers were fabricated using the shadow-evaporation technique and measured at low temperatures, T≈25mK. Due to high junction transparency, IV characteristics showed only small hysteresis a retrapping-to-switching current ratio of up 80%. The observed critical currents as large 80%-100% Ambegaokar-Baratoff values. High barrier quality was confirmed by subgap leakage in quasiparticle branches, which makes hysteretic Al promising for...
We report on the development and test of an integrated system composed a flux qubit rapid single-flux quantum (RSFQ) circuit that allows manipulation. The goal is to demonstrate feasibility control electronics same chip as qubit, in view application computation with superconducting devices.
We demonstrate that shunting of superconductor-insulator-superconductor (S-I-S) Josephson junctions by superconductor-insulator-normal metal (S-I-N) structures having pronounced nonlinear I–V characteristics can remarkably modify the dynamics. In regime generation phase behaves as an overdamped coordinate, while in superconducting state damping and current noise are strikingly small, is vitally important for application such readout control qubits. Superconducting Nb/AlOx/Nb junction shunted...
The fault-free switching of single-flux-quantum (SFQ) elements was studied by investigating SFQ pulse propagation in a ring Josephson transmission line closed with an inverter. A lifetime more than few hours obtained that corresponds to at least 10/sup 15/ switching. completely DC-powered rapid (RSFQ) sampler used directly measure the repetition rate stability generator loaded uniformly shunted line. stable up 7 GHz obtained. authors also report experimental results for two-stage serial and...
The authors propose a new type of sampler design based on shunted junctions ( beta c=1). is to be used for the investigation single flux quantum devices (RSFQ) employing similar (Kaplunenko et al. 1989, Filippenko 1991). They measure time resolution and delay Josephson junction array. circuit was manufactured chip DC powered. employed Nb-AlOx-Nb tunnel 300 A m-2 critical current density observed oscillations output at frequencies from 6 50 GHz. Despite long plasma period 20 ps 5 ps....
Within the framework of microscopic model tunneling, we modeled behavior Josephson junction shunted by superconductor--insulator--normal-metal (SIN) tunnel junction. The electromagnetic impedance SIN includes both frequency-dependent damping and reactance, which affect circuit dynamics. We calculated dc $I\text{\ensuremath{-}}V$ curves transient characteristics show their differences to obtained within simpler models. correct operation basic single-flux-quantum circuits, i.e., transmission...
The reduction of the critical current density in rapid single-flux quantum (RSFQ) circuits enables new application fields, like computing and photonic detector readout. low fabrication process creates design challenges, such as lower stability against thermal fluctuations, violation lumped elements condition for microstrip inductances increased sensitivity to technological spread. To overcome these issues, we suggest a passive phase shifter promising alternative technique superconductive...
We have developed integrated circuits in rapid single flux quantum (RSFQ) impulse logic based on intrinsically shunted tunnel junctions as the active circuit elements. The been fabricated using superconductor-insulator-normalconductor-insulator-superconductor (SINIS) multilayer technology. paper presents experimental results of operation various RSFQ realized different designs and layouts. comprise dc/SFQ SFQ/dc converters, Josephson transmission lines (JTLs), T-flipflops, analog key...
At the typical operating temperature of 4.2 K, theoretical upper limit clock frequency Low-Temperature Superconductive (LTS) Nb based Rapid Single Flux Quantum (RSFQ) digital circuits is several hundred GHz. Nevertheless, few middle-scale RSFQ reported on up to now operate at only some tens An important performance-limiting factor in this case signal distribution, so nowadays asynchronous designs are often considered. Our previous studies have shown that it an advantage a given cell library...
At PTB, the fabrication process in Nb-Al/Al/sub x/O/sub y//Al/Al/sub y//Al-Nb SINIS multilayer technology has been improved to raise characteristic voltage of two-tunnel Josephson junctions up V/sub C/=I/sub C/R/sub n/=245 /spl mu/V. The realized LTS implementation. Various sets test wafers and containing dc/SFQ SFQ/dc converters, transmission lines, T-flipflop circuits were fabricated measured. critical current densities have varied range from 70 A/cm/sup 2/ 2.2 kA/cm/sup with corresponding...
We investigated both theoretically and experimentally open-ended coplanar waveguide resonators with rf SQUIDs embedded in the central conductor at different positions. These can be tuned by an external magnetic field thus may exhibit non-centrosymmetric nonlinearity of $\chi^{(2)}$ type suppressed Kerr nonlinearity. demonstrated that this allows for efficient mixing $\lambda/2$ $\lambda$ modes cavity enables various parametric effects three wave mixing. are second harmonic generation, half...
At PTB, a new type of fabrication process has been developed to verify rapid single flux quantum (RSFQ) integrated circuits based on intrinsically shunted two-tunnel Josephson junctions (JJs). The realized in LTS implementation using SINIS technology. A variety JJs, junction arrays and test have fabricated experimentally investigated. critical current densities the were set nominal value jC = 500 cm-2, with values characteristic voltage VC equal or larger than 160 µV. JJs show nearly...
The novel element of the rapid single flux quantum (RSFQ) logic family-the quasi digital voltage amplifier (QDVA)-which was recently proposed theoretically, has now been designed and experimentally investigated. QDVA can be employed both as a in circuits analogue amplifier. correct operation SFQ doubler demonstrated up to output 0.5 mV with very large margins (up 60%). integrated on same chip SQUID sensor; it significantly simplifies matching seems attractive for multichannel systems.
The paper presents the determination of high-frequency performance Rapid Single Flux Quantum (RSFQ) circuits fabricated in superconductor-insulator-normal metal-insulator-superconductor (SINIS) technology. Circuits different designs have been realized and were experimentally investigated, including specially designed T flip-flop (TFF) structures consisting a switch terminated Josephson transmission lines. For TFF circuits, operational functionality was investigated frequency range from dc up...
The SNS (Nb/HfTi/Nb) ramp junction technology process has been improved for digital superconducting circuit operation. DC interferometers were realized on an isolated ground plane, connections being through windows in the insulation layers. inductances of Nb striplines (widths w down to sub-/spl mu/m range) measured. For a 250 nm SiO/sub 2//Nb-oxide layer, sheet determined at 0.382 /spl plusmn/ 0.009, 0.340 0.005, and 0.293 0.008 pH (stripline widths: 1.5, 1.0, 0.54 mu/m) compared with data...