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 Instrumentation and Measurement

Operating Margins for a Pulse-Driven Josephson Arbitrary Waveform Synthesizer Using a Ternary Bit-Stream Generator

Ernest Houtzager, Samuel P. Benz, Helko E. van den Brom

Published Dec 18, 2008• 32 citations
Publisher

Abstract

We describe measurements with a pulse-driven Josephson arbitrary waveform synthesizer (JAWS) that uses a ternary arbitrary bit-stream generator as the bias source. This system is designed to be used as an AC Josephson voltage standard. From these measurements, we conclude that the system is operational for root-mean-square voltages of up to 220 mV. We measured the operating margins for different voltages synthesized with different numbers of junctions, waveforms, and bias conditions. We also present results on the influence of the critical current on the operating margins.

DOI
10.1109/tim.2008.2008471

Related papers

Towards a 1 V Josephson Arbitrary Waveform Synthesizer

Oliver Kieler, Ralf Behr, Ruediger Wendisch +3 more

The establishment at PTB of an AC Josephson voltage standard (Josephson Arbitrary Waveform Synthesizer- JAWS) based on pulse-driven Josephson arrays is focused on achieving an output voltage of at least 1 Vrms which is required for many metrology applications. In this paper, we approached this goal by increasing the number of active junctions in two ways. Firstly, we fabricated arrays containing triple-stacked SNS-type Josephson junctions with NbxSi1-xas barrier material. We obtained current operation margins of about 0.2 mA with arrays of up to 9000 Josephson junctions at an rms voltage of 355 mV. Secondly, we used a new 8-channel ternary pulse pattern generator (PPG) to bias up to 8 arrays connected in series. An output voltage of VRMS= 1006 mV(VPP= 2.845 V) was achieved by using 8 arrays (arranged on 4 separate chips) with 63000 junctions in total. Higher harmonics are suppressed by at least -116 dBc. The fabrication process and the experimental setup will be described, as well as experimental results that are leading towards our 1 V goal.

IEEE Transactions on Applied Superconductivity•Nov 10, 2014•97 citations

Pulse-Bias Electronics and Techniques for a Josephson Arbitrary Waveform Synthesizer

Samuel P. Benz, Steven B. Waltman

The Josephson arbitrary waveform synthesizer (JAWS) is a series array of thousands of superconducting Josephson junctions that are biased by current pulses such that the array produces voltage waveforms with quantum accuracy. Intrinsically accurate voltage waveforms synthesized with the quantized pulses from Josephson junctions were first demonstrated in 1996. Ten years later, a commercial ac standard was calibrated at an output root-mean-square (RMS) amplitude of 100 mV with the first practical superconducting digital-to-analog converter. Since then, many different bias techniques, pulse-drive electronics, and device technology have been developed and improved in order to achieve a maximum of 138 mV output RMS voltage per Josephson array. In this paper, we report new bias electronics and demonstrate two new pulse-bias techniques. The first technique has demonstrated 250 mV output RMS voltage per 6400-junction array and may enable a practical 1 V system with only four arrays. The second bias technique reduces inductance-related error signals at the signal frequency and should reduce systematic errors for waveforms with frequencies greater than 1 MHz.

IEEE Transactions on Applied Superconductivity•Jul 11, 2014•40 citations

Josephson Arbitrary Waveform Synthesizer With Two Layers of Wilkinson Dividers and an FIR Filter

Nathan E. Flowers-Jacobs, Steven B. Waltman, Anna E. Fox +2 more

The output voltage of Josephson arbitrary waveform synthesizers (JAWS) is limited by the number of Josephson junctions (JJs) that can be driven by a single pulse-generator channel. Here, we double the number of JJs driven by one generator channel to 51 200 JJs by distributing the pulse bias between four JJ arrays by use of two layers of Wilkinson dividers. We use this single bias to generate a voltage at 1 kHz with an rms magnitude of 1 V. This voltage is quantum-accurate over an operating current range of 1.4 mA. For comparison, the operating current range of a recent design that uses a single layer of Wilkinson dividers is twice as large, but requires two pulse-bias channels to generate 1 V. We also show that we can recover this performance by incorporating in the pulse generator a finite-impulse response (FIR) filter that acts as an equalizer. The FIR filter creates a custom transfer function that compensates for the bandwidth-limited transfer function of the Wilkinson dividers. Optimizing the FIR filter parameters increases the operating current range from 1.4 to 2.7 mA. This ability to drive additional JJ arrays with a single pulse-generator channel will enable future JAWS chips and systems to achieve significantly larger output voltages. This will increase the voltage range for JAWS calibrations of ac thermal converters and improve precision voltage measurements that require quantum-accurate, stable, and distortion-free waveforms with a large signal-to-noise ratio.

IEEE Transactions on Applied Superconductivity•Jun 23, 2016•32 citations

Two-Volt Josephson Arbitrary Waveform Synthesizer Using Wilkinson Dividers

Nathan E. Flowers-Jacobs, Anna E. Fox, Paul D. Dresselhaus +2 more

The root-mean-square (rms) output voltage of the NIST Josephson arbitrary waveform synthesizer (JAWS) has been doubled from 1 V to a record 2 V by combining two new 1 V chips on a cryocooler. This higher voltage will improve calibrations of ac thermal voltage converters and precision voltage measurements that require state-of-the-art quantum accuracy, stability, and signal-to-noise ratio. We achieved this increase in output voltage by using four on-chip Wilkinson dividers and eight inner-outer dc blocks, which enable biasing of eight Josephson junction (JJ) arrays with high-speed inputs from only four high-speed pulse generator channels. This approach halves the number of pulse generator channels required in future JAWS systems. We also implemented on-chip superconducting interconnects between JJ arrays, which reduces systematic errors and enables a new modular chip package. Finally, we demonstrate a new technique for measuring and visualizing the operating current range that reduces the measurement time by almost two orders of magnitude and reveals the relationship between distortion in the output spectrum and output pulse sequence errors.

IEEE Transactions on Applied Superconductivity•Feb 19, 2016•76 citations

SNS josephson junction series arrays for the Josephson Arbitrary Waveform Synthesizer

J. Kohlmann, Oliver Kieler, Ricardo Iuzzolino +3 more

AC voltages and arbitrary waveforms are synthesized by Josephson junctions operated by short current pulses. Series arrays of intrinsically shunted SNS Josephson junctions were developed and investigated for applications in this Josephson Arbitrary Waveform Synthesizer (JAWS). Amplitudes above 200 mV were generated by series arrays consisting of more than 10,000 junctions arranged in a meander-like design.

Conference on Precision Electromagnetic Measurements•Jun 1, 2008•3 citations

Bipolar Pulse-Drive Electronics for a Josephson Arbitrary Waveform Synthesizer

Helko E. van den Brom, Ernest Houtzager, B. Brinkmeier +1 more

A Josephson arbitrary waveform synthesizer (JAWS) has been developed in order to generate quantum-based ac voltage signals. The key component of this JAWS is a modified commercial 30-Gb/s pattern generator that can generate ternary patterns (containing the values 1, 0, and 1, resulting in bipolar pulses). The new pulse-drive electronics have been successfully tested by driving Josephson arrays with bipolar current pulses from 1 to 30 Gb/s in order to study their current-voltage characteristics and the spectra of the JAWS signals.

IEEE Transactions on Instrumentation and Measurement•Jan 1, 2008•28 citations
We describe measurements with a pulse-driven Josephson arbitrary waveform synthesizer (JAWS) that uses a ternary arbitrary bit-stream generator as the bias source. This system is designed to be used as an AC Josephson voltage standard. From these measurements, we conclude that the system is operational for root-mean-square voltages of up to 220 mV. We measured the operating margins for different voltages synthesized with different numbers of junctions, waveforms, and bias conditions. We also present results on the influence of the critical current on the operating margins.
The establishment at PTB of an AC Josephson voltage standard (Josephson Arbitrary Waveform Synthesizer- JAWS) based on pulse-driven Josephson arrays is focused on achieving an output voltage of at least 1 Vrms which is required for many metrology applications. In this paper, we approached this goal by increasing the number of active junctions in two ways. Firstly, we fabricated arrays containing triple-stacked SNS-type Josephson junctions with NbxSi1-xas barrier material. We obtained current operation margins of about 0.2 mA with arrays of up to 9000 Josephson junctions at an rms voltage of 355 mV. Secondly, we used a new 8-channel ternary pulse pattern generator (PPG) to bias up to 8 arrays connected in series. An output voltage of VRMS= 1006 mV(VPP= 2.845 V) was achieved by using 8 arrays (arranged on 4 separate chips) with 63000 junctions in total. Higher harmonics are suppressed by at least -116 dBc. The fabrication process and the experimental setup will be described, as well as experimental results that are leading towards our 1 V goal.
The Josephson arbitrary waveform synthesizer (JAWS) is a series array of thousands of superconducting Josephson junctions that are biased by current pulses such that the array produces voltage waveforms with quantum accuracy. Intrinsically accurate voltage waveforms synthesized with the quantized pulses from Josephson junctions were first demonstrated in 1996. Ten years later, a commercial ac standard was calibrated at an output root-mean-square (RMS) amplitude of 100 mV with the first practical superconducting digital-to-analog converter. Since then, many different bias techniques, pulse-drive electronics, and device technology have been developed and improved in order to achieve a maximum of 138 mV output RMS voltage per Josephson array. In this paper, we report new bias electronics and demonstrate two new pulse-bias techniques. The first technique has demonstrated 250 mV output RMS voltage per 6400-junction array and may enable a practical 1 V system with only four arrays. The second bias technique reduces inductance-related error signals at the signal frequency and should reduce systematic errors for waveforms with frequencies greater than 1 MHz.
The output voltage of Josephson arbitrary waveform synthesizers (JAWS) is limited by the number of Josephson junctions (JJs) that can be driven by a single pulse-generator channel. Here, we double the number of JJs driven by one generator channel to 51 200 JJs by distributing the pulse bias between four JJ arrays by use of two layers of Wilkinson dividers. We use this single bias to generate a voltage at 1 kHz with an rms magnitude of 1 V. This voltage is quantum-accurate over an operating current range of 1.4 mA. For comparison, the operating current range of a recent design that uses a single layer of Wilkinson dividers is twice as large, but requires two pulse-bias channels to generate 1 V. We also show that we can recover this performance by incorporating in the pulse generator a finite-impulse response (FIR) filter that acts as an equalizer. The FIR filter creates a custom transfer function that compensates for the bandwidth-limited transfer function of the Wilkinson dividers. Optimizing the FIR filter parameters increases the operating current range from 1.4 to 2.7 mA. This ability to drive additional JJ arrays with a single pulse-generator channel will enable future JAWS chips and systems to achieve significantly larger output voltages. This will increase the voltage range for JAWS calibrations of ac thermal converters and improve precision voltage measurements that require quantum-accurate, stable, and distortion-free waveforms with a large signal-to-noise ratio.
The root-mean-square (rms) output voltage of the NIST Josephson arbitrary waveform synthesizer (JAWS) has been doubled from 1 V to a record 2 V by combining two new 1 V chips on a cryocooler. This higher voltage will improve calibrations of ac thermal voltage converters and precision voltage measurements that require state-of-the-art quantum accuracy, stability, and signal-to-noise ratio. We achieved this increase in output voltage by using four on-chip Wilkinson dividers and eight inner-outer dc blocks, which enable biasing of eight Josephson junction (JJ) arrays with high-speed inputs from only four high-speed pulse generator channels. This approach halves the number of pulse generator channels required in future JAWS systems. We also implemented on-chip superconducting interconnects between JJ arrays, which reduces systematic errors and enables a new modular chip package. Finally, we demonstrate a new technique for measuring and visualizing the operating current range that reduces the measurement time by almost two orders of magnitude and reveals the relationship between distortion in the output spectrum and output pulse sequence errors.
A Josephson arbitrary waveform synthesizer (JAWS) has been developed in order to generate quantum-based ac voltage signals. The key component of this JAWS is a modified commercial 30-Gb/s pattern generator that can generate ternary patterns (containing the values 1, 0, and 1, resulting in bipolar pulses). The new pulse-drive electronics have been successfully tested by driving Josephson arrays with bipolar current pulses from 1 to 30 Gb/s in order to study their current-voltage characteristics and the spectra of the JAWS signals.