Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

IEEE Transactions on Applied Superconductivity

Operating margins for a pulse-driven programmable voltage standard

Samuel P. Benz, Charles J. Burroughs, C.A. Hamilton

Published Jun 1, 1997• 19 citations
Publisher

Abstract

We have designed and fabricated a Josephson voltage standard where the voltage can be rapidly and continuously programmed by changing the repetition frequency of a pulse drive. Simulations are made to optimize the operating margins of the circuit for different pulse waveforms. The response of a 1000-junction array of Nb-PdAu-Nb junctions is measured, and constant-voltage step heights are characterized as a function the pulse amplitude, pulse width, frequency. A DC bias range of 0.62 mA is demonstrated over a continuous voltage-tunable range from -6.2 mV to +6.5 mV.

DOI
10.1109/77.621784

Related papers

SNS programmable voltage standard

C.A. Hamilton, Samuel P. Benz, Charles J. Burroughs +1 more

Superconductor-Normal-Superconductor (SNS) junctions have been used in the design and fabrication of a 1-V rapidly programmable voltage standard. The superconducting circuit is a series array of 32 768 Nb-PdAu-Nb junctions with taps that divide the array into a binary sequence of smaller array segments with a minimum segment size of 128 junctions. The 16-GHz drive frequency is set by the characteristic frequency of the junctions. A computer-controlled 8-channel bias system controls the current in each segment and allows the rapid selection of any one of 513 discrete voltage levels. The system is designed for fast dc measurements and the synthesis of precise ac waveforms.

IEEE Transactions on Applied Superconductivity•Jun 1, 1997•26 citations

Precision Measurements of AC Josephson Voltage Standard Operating Margins

Charles J. Burroughs, Samuel P. Benz, Paul D. Dresselhaus +1 more

Recent advances in circuit design and fabrication of superconducting integrated circuits have enabled us to demonstrate an ac Josephson voltage standard (ACJVS) that generates both ac and dc waveforms up to 242-mV peak voltage. Using a Fast Fourier Transform spectrum analyzer and an ac-dc transfer standard, we characterize ACJVS operating margins by performing "flat-spot" measurements at the level of a part in 10/sup 6/ for all eight bias parameters. By verifying that every bias parameter has a "flat-spot" (i.e., a range of bias values over which the measured ACJVS output is precisely constant), we demonstrate that all Josephson junctions on the chip are operating properly.

IEEE Transactions on Instrumentation and Measurement•Mar 21, 2005•40 citations

Superconductor-normal-superconductor junctions for programmable voltage standards

S. P. Benz

Series arrays of Nb–PdAu–Nb Josephson junctions were fabricated with characteristics ideally suited for application in programmable voltage standards and D/A converters with fundamental accuracy. Large arrays of junctions with applied microwave power showed constant voltage steps with current amplitudes as large as 7 mA. A novel coplanar waveguide design enabled uniform microwave power coupling to a five-segment array of 8192 junctions, so each segment had constant voltage steps over the same bias range. The 8192-junction device generated 1.1 mA steps at 186 mV with 11 GHz power and a maximum constant voltage step of 260 mV at 15.34 GHz.

Applied Physics Letters•Oct 30, 1995•133 citations

Programmable Josephson Voltage Standard Circuits Using Arrays of NbN/TiN/NbN/TiN/NbN Double-Junction Stacks Operated at 10 K

Mayumi Ishizaki, Hirotake Yamamori, Alexandre Shoji +2 more

Programmable Josephson voltage standard (PJVS) circuits using arrays of NbN/TiN/NbN/TiN/NbN double-junction stacks were fabricated and operated at a temperature of 10 K. Four arrays each with 32 768 junctions produced expected voltage outputs when driven at (10, 15, 17, and 20) GHz with an operating current range of 0.2-1.0 mA. Another circuit showed constant-voltage steps at /spl plusmn/6 V when driven with an 11 GHz microwave bias, indicating that over 260 000 junctions were operating properly. This circuit did not show constant-voltage steps when driven with a 19 GHz microwave bias, which was the design frequency to achieve /spl plusmn/10 V output voltage.

IEEE Transactions on Instrumentation and Measurement•Mar 21, 2005•11 citations

Constant-voltage steps in arrays of Nb-PdAu-Nb Josephson junctions

Samuel P. Benz, Charles J. Burroughs

Design and fabrication of Nb-PdAu-Nb trilayer Josephson junctions are described. The microwave response of an array of 1000 of these junctions was measured, and constant-voltage step heights mere characterized as a function of the microwave amplitude and frequency. Experimental results fit well to point-junction simulations at the 3 GHz design frequency of the microwave distribution network. The observed step height of 3.8 mA shows that the array and microwave distribution are sufficiently uniform for application in programmable Josephson voltage standards.

IEEE Transactions on Applied Superconductivity•Jun 1, 1997•24 citations

10 Volt Programmable Josephson Voltage Standard Circuits Using NbSi-Barrier Junctions

Paul D. Dresselhaus, Michael M. Elsbury, David I. Olaya +2 more

Programmable Josephson voltage standard (PJVS) circuits were developed that operate at 16 GHz to 20 GHz with operating margins larger than 1 mA. Two circuit designs were demonstrated, each having a total of ~ 300,000 junctions, which were divided into either 16 or 32 sub-arrays. Triple-stacked junctions were used in order to fit the ~300,000 junctions on each circuit. The amorphous NbxSi1-x-barrier junction technology provided a high degree of uniformity of the barrier and junction electrical properties, which was necessary to achieve the 1 mA operating margin. Although the margins on both the 16-array and 32-array circuits were much greater than 1 mA, the circuit yield for the 16-array design was lower because the longer arrays are more sensitive to defects. The use of lumped-element microwave splitters and tapered arrays significantly reduced the microwave input power and increased the operating margins of these designs. In addition, the broadband microwave response of the designs allowed the PJVS output voltage to be continuously adjusted by using the microwave frequency while remaining on margins.

IEEE Transactions on Applied Superconductivity•Nov 9, 2010•59 citations
We have designed and fabricated a Josephson voltage standard where the voltage can be rapidly and continuously programmed by changing the repetition frequency of a pulse drive. Simulations are made to optimize the operating margins of the circuit for different pulse waveforms. The response of a 1000-junction array of Nb-PdAu-Nb junctions is measured, and constant-voltage step heights are characterized as a function the pulse amplitude, pulse width, frequency. A DC bias range of 0.62 mA is demonstrated over a continuous voltage-tunable range from -6.2 mV to +6.5 mV.
Superconductor-Normal-Superconductor (SNS) junctions have been used in the design and fabrication of a 1-V rapidly programmable voltage standard. The superconducting circuit is a series array of 32 768 Nb-PdAu-Nb junctions with taps that divide the array into a binary sequence of smaller array segments with a minimum segment size of 128 junctions. The 16-GHz drive frequency is set by the characteristic frequency of the junctions. A computer-controlled 8-channel bias system controls the current in each segment and allows the rapid selection of any one of 513 discrete voltage levels. The system is designed for fast dc measurements and the synthesis of precise ac waveforms.
Recent advances in circuit design and fabrication of superconducting integrated circuits have enabled us to demonstrate an ac Josephson voltage standard (ACJVS) that generates both ac and dc waveforms up to 242-mV peak voltage. Using a Fast Fourier Transform spectrum analyzer and an ac-dc transfer standard, we characterize ACJVS operating margins by performing "flat-spot" measurements at the level of a part in 10/sup 6/ for all eight bias parameters. By verifying that every bias parameter has a "flat-spot" (i.e., a range of bias values over which the measured ACJVS output is precisely constant), we demonstrate that all Josephson junctions on the chip are operating properly.
Series arrays of Nb–PdAu–Nb Josephson junctions were fabricated with characteristics ideally suited for application in programmable voltage standards and D/A converters with fundamental accuracy. Large arrays of junctions with applied microwave power showed constant voltage steps with current amplitudes as large as 7 mA. A novel coplanar waveguide design enabled uniform microwave power coupling to a five-segment array of 8192 junctions, so each segment had constant voltage steps over the same bias range. The 8192-junction device generated 1.1 mA steps at 186 mV with 11 GHz power and a maximum constant voltage step of 260 mV at 15.34 GHz.
Programmable Josephson voltage standard (PJVS) circuits using arrays of NbN/TiN/NbN/TiN/NbN double-junction stacks were fabricated and operated at a temperature of 10 K. Four arrays each with 32 768 junctions produced expected voltage outputs when driven at (10, 15, 17, and 20) GHz with an operating current range of 0.2-1.0 mA. Another circuit showed constant-voltage steps at /spl plusmn/6 V when driven with an 11 GHz microwave bias, indicating that over 260 000 junctions were operating properly. This circuit did not show constant-voltage steps when driven with a 19 GHz microwave bias, which was the design frequency to achieve /spl plusmn/10 V output voltage.
Design and fabrication of Nb-PdAu-Nb trilayer Josephson junctions are described. The microwave response of an array of 1000 of these junctions was measured, and constant-voltage step heights mere characterized as a function of the microwave amplitude and frequency. Experimental results fit well to point-junction simulations at the 3 GHz design frequency of the microwave distribution network. The observed step height of 3.8 mA shows that the array and microwave distribution are sufficiently uniform for application in programmable Josephson voltage standards.
Programmable Josephson voltage standard (PJVS) circuits were developed that operate at 16 GHz to 20 GHz with operating margins larger than 1 mA. Two circuit designs were demonstrated, each having a total of ~ 300,000 junctions, which were divided into either 16 or 32 sub-arrays. Triple-stacked junctions were used in order to fit the ~300,000 junctions on each circuit. The amorphous NbxSi1-x-barrier junction technology provided a high degree of uniformity of the barrier and junction electrical properties, which was necessary to achieve the 1 mA operating margin. Although the margins on both the 16-array and 32-array circuits were much greater than 1 mA, the circuit yield for the 16-array design was lower because the longer arrays are more sensitive to defects. The use of lumped-element microwave splitters and tapered arrays significantly reduced the microwave input power and increased the operating margins of these designs. In addition, the broadband microwave response of the designs allowed the PJVS output voltage to be continuously adjusted by using the microwave frequency while remaining on margins.