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

Applied Sciences

A 300 mV Josephson Arbitrary Waveform Synthesizer Chip at NIM

Weiyuan Jia, Jiuhui Song, Yuan Zhong, Kunli Zhou, Qina Han, Wenhui Cao, Jinjin Li, Jinhui Cai, Jun Wan, Ziyi Zhao

Published Nov 5, 2025• 1 citation
Publisher

Abstract

This paper describes the status of developing Josephson arbitrary waveform synthesizer (JAWS) chips at NIM (National Institute of Metrology, China). To obtain high junction integration density and fewer data input channels, the chip employs an on-chip Wilkinson power divider and inside/outside dc blocks, enabling both arrays to be driven by a single pulse-generator channel. In addition, the tapered coplanar waveguide structure is used to ensure the microwave uniformity of the long-junction array. Each array consisted of 4000 double-stack Nb/NbxSi1−x/Nb junctions, and 16,000 junctions are integrated in the chip in total. The JAWS chip demonstrates good performance, capable of synthesizing a 300 mV root mean square (rms) voltage with exceptionally low harmonic distortion. Dc and ac voltage-current characteristics measurements indicate that the junctions are with a critical current of 2.5 mA, and a normal-state resistance of 4.5 mΩ per junction. Contact aligners are manually operated to fabricate the chips, and process errors in the fabrication are estimated in this paper.

DOI
10.3390/app152111811

Related papers

300 mV Josephson Arbitrary Waveform Synthesizer Chip in NIM

Yuan Zhong, Qing Zhong, Wenhui Cao +3 more

This paper describes the current status of developing Josephson arbitrary waveform synthesizer (JAWS) chips in NIM (National Institute of Metrology, China). The chip has one data input channel and two Josephson junction arrays, each array consisted by 4000 double-stack Nb/NbxSi1–x/Nb junctions. The two arrays were driven with a single pulse-generator channel by using one on-chip Wilkinson power divider and inside/outside DC blocks. Root-mean-square (rms) output magnitude of 300 mV was generated with this JAWS chip.

Conference on Precision Electromagnetic Measurements•Jul 8, 2024•1 citation

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

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

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

Investigation of Broadband Wilkinson Power Dividers for Pulse-Driven Josephson Voltage Standards

Hao Tian, Oliver Kieler, Ralf Behr +3 more

This paper describes recent developments for increasing the output voltage of the Josephson Arbitrary Waveform Synthesizer (JAWS) at PTB. For this purpose, we developed modified broadband Wilkinson power dividers, which enable the operation of two or four Josephson junction series arrays per RF channel of the pulse pattern generator and thus the generation of increased output voltages. In detail, we designed and investigated two different Wilkinson power dividers: the one-stage three-section Wilkinson power divider with extended bandwidth and the two-stage single-section Wilkinson divider with more outputs to combine four parallel series arrays. They were both integrated with triple-stacked Josephson junction series arrays. Additionally, a new modulator pulse amplifier was introduced into the JAWS set-up to provide sufficient power for all the junction arrays. Our measurement results show that spectrally pure sinusoidal waveforms were successfully generated with both types of power dividers. With the one-stage three-section Wilkinson power divider, we obtained RMS voltages of nearly 53 mV at a clock-frequency of 15 GHz combined with a test array of 3000 Josephson junctions. As for the two-stage single-section Wilkinson power divider combined with a test array of 6000 Josephson junctions, we synthesized RMS output voltages of about 105 mV. These test results show a promising prospect for quantum voltage standard applications.

IEEE Transactions on Applied Superconductivity•Jan 28, 2021•7 citations

Performance Improvements for the NIST 1 V Josephson Arbitrary Waveform Synthesizer

Samuel P. Benz, Steven B. Waltman, Anna E. Fox +5 more

The performance of the NIST Josephson arbitrary waveform synthesizer has been improved such that it generates a root-mean-square (rms) output voltage of 1 V with an operating current range greater than 2 mA. Our previous 1 V JAWS circuit achieved this same maximum voltage over a current range of 0.4 mA by operating every Josephson junction in its second quantum state. The newest circuit synthesizes 1 V waveforms with the junctions operating in the first quantum state. The voltage per array is doubled because the number of junctions in each array was doubled through the use of improved microwave circuit designs that increased the bias uniformity to the junctions. We describe the circuit improvements and device operation, and we demonstrate the system capabilities by showing measured spectra of a 1 Hz sine wave and a dual-tone waveform. With only two arrays of the new circuit, we also synthesized a 128 mV sine wave without a compensation bias signal, which is one of the bias signals required for achieving 1 V. This is the same rms output voltage achieved with the previous circuit using four arrays.

IEEE Transactions on Applied Superconductivity•Nov 10, 2014•29 citations
This paper describes the status of developing Josephson arbitrary waveform synthesizer (JAWS) chips at NIM (National Institute of Metrology, China). To obtain high junction integration density and fewer data input channels, the chip employs an on-chip Wilkinson power divider and inside/outside dc blocks, enabling both arrays to be driven by a single pulse-generator channel. In addition, the tapered coplanar waveguide structure is used to ensure the microwave uniformity of the long-junction array. Each array consisted of 4000 double-stack Nb/NbxSi1−x/Nb junctions, and 16,000 junctions are integrated in the chip in total. The JAWS chip demonstrates good performance, capable of synthesizing a 300 mV root mean square (rms) voltage with exceptionally low harmonic distortion. Dc and ac voltage-current characteristics measurements indicate that the junctions are with a critical current of 2.5 mA, and a normal-state resistance of 4.5 mΩ per junction. Contact aligners are manually operated to fabricate the chips, and process errors in the fabrication are estimated in this paper.
This paper describes the current status of developing Josephson arbitrary waveform synthesizer (JAWS) chips in NIM (National Institute of Metrology, China). The chip has one data input channel and two Josephson junction arrays, each array consisted by 4000 double-stack Nb/NbxSi1–x/Nb junctions. The two arrays were driven with a single pulse-generator channel by using one on-chip Wilkinson power divider and inside/outside DC blocks. Root-mean-square (rms) output magnitude of 300 mV was generated with this JAWS chip.
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.
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 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.
This paper describes recent developments for increasing the output voltage of the Josephson Arbitrary Waveform Synthesizer (JAWS) at PTB. For this purpose, we developed modified broadband Wilkinson power dividers, which enable the operation of two or four Josephson junction series arrays per RF channel of the pulse pattern generator and thus the generation of increased output voltages. In detail, we designed and investigated two different Wilkinson power dividers: the one-stage three-section Wilkinson power divider with extended bandwidth and the two-stage single-section Wilkinson divider with more outputs to combine four parallel series arrays. They were both integrated with triple-stacked Josephson junction series arrays. Additionally, a new modulator pulse amplifier was introduced into the JAWS set-up to provide sufficient power for all the junction arrays. Our measurement results show that spectrally pure sinusoidal waveforms were successfully generated with both types of power dividers. With the one-stage three-section Wilkinson power divider, we obtained RMS voltages of nearly 53 mV at a clock-frequency of 15 GHz combined with a test array of 3000 Josephson junctions. As for the two-stage single-section Wilkinson power divider combined with a test array of 6000 Josephson junctions, we synthesized RMS output voltages of about 105 mV. These test results show a promising prospect for quantum voltage standard applications.
The performance of the NIST Josephson arbitrary waveform synthesizer has been improved such that it generates a root-mean-square (rms) output voltage of 1 V with an operating current range greater than 2 mA. Our previous 1 V JAWS circuit achieved this same maximum voltage over a current range of 0.4 mA by operating every Josephson junction in its second quantum state. The newest circuit synthesizes 1 V waveforms with the junctions operating in the first quantum state. The voltage per array is doubled because the number of junctions in each array was doubled through the use of improved microwave circuit designs that increased the bias uniformity to the junctions. We describe the circuit improvements and device operation, and we demonstrate the system capabilities by showing measured spectra of a 1 Hz sine wave and a dual-tone waveform. With only two arrays of the new circuit, we also synthesized a 128 mV sine wave without a compensation bias signal, which is one of the bias signals required for achieving 1 V. This is the same rms output voltage achieved with the previous circuit using four arrays.