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

Superconductor Science and Technology

The simulation and measurement of the response of Josephson junctions to optoelectronically generated short pulses

Jonathan M. J. Williams, T. J. B. M. Janssen, L. Palafox, David A. Humphreys, Ralf Behr, J. Kohlmann, F Müller

Published Apr 29, 2004• 56 citations
Publisher

Abstract

A new method of driving series arrays of non-hysteretic Josephson junctions using optoelectronically generated pulses to synthesize a variable output voltage is described. Electrical pulses from a photodiode are coupled to the array, and the mean output voltage after filtering is proportional to the pulse repetition frequency with fundamental accuracy. Numerical simulations of the behaviour of the Josephson junctions have been carried out, and these results have been verified by experiment. This technique can be easily extended by using two photodiodes with opposite bias polarities in order to synthesize bipolar alternating or direct voltages.

DOI
10.1088/0953-2048/17/6/014

Related papers

An optoelectronic coupling for pulse-driven Josephson junction arrays

Jane Ireland, Dale Henderson, Jonathan M. J. Williams +7 more

The optoelectronic coupling for a pulse-driven Josephson junction array (JJA) for use as a quantum voltage synthesizer has been designed. This system uses optoelectronic components to drive a group of JJAs in parallel. Since the drive system is electrically isolated from the JJAs, they can be connected in series, leading to a higher output voltage. A thin film circuit, including interdigitated capacitors to couple a photodiode to the JJAs has been designed and tested and shown to meet the design goals.

Conference on Precision Electromagnetic Measurements•Aug 1, 2014•5 citations

Bipolar Waveform Synthesis With an Optically Driven Josephson Arbitrary Waveform Synthesizer

Justus A. Brevik, Dahyeon Lee, Anna E. Fox +6 more

An array of Josephson junctions (JJs) was driven with photonically generated current pulses to synthesize a high-fidelity 1 kHz bipolar voltage waveform with a quantum-based amplitude that can be directly related to fundamental constants. A photodiode capable of producing high average photocurrent was used to generate large-amplitude current pulses that were ac-coupled to a JJ array. The resulting bipolar current pulses have enabled the first demonstration of quantum-based bipolar waveform synthesis with an optical drive. We measured the quantum locking range with respect to several operating parameters, including 1.2 mA with respect to a dc bias current applied to the array, confirming the robust synthesis of bipolar waveforms.

IEEE Transactions on Applied Superconductivity•Apr 19, 2022•13 citations

Josephson Arbitrary Waveform System with Optoelectronic Drive

Jane Ireland, Oliver Kieler, J. Kohlmann +10 more

Quantum-accurate arbitrary voltage waveforms have been generated using electrical pulse driven Josephson junction arrays (JJAs) by several groups [1, 2]. An alternative method is to use optoelectronic components to convert the electrical pulse drive into an optical signal which is subsequently converted by a photodiode into an electrical drive signal connected directly to the JJA. This optoelectronic pulse drive system has several advantages. Due to the electrical isolation between electrical pulse drive and JJA, it is possible to connect several arrays in series without the requirement for complex electrical compensation circuits. This allows larger output voltages to be realized. An optoelectronic drive also offers the ability to easily tune pulse height, via continuous optical attenuation, allowing the drive signal to be tuned to the middle of the JJA constant voltage step giving optimum operation margins. We here present an optoelectronic pulse drive which forms part of a system incorporating a JJA and delta sigma feedback loop [3] for quantum-accurate digitization of arbitrary voltage waveforms. Results showing the generation of quantum-accurate voltages synchronized to the feedback loop master clock are presented.

IEEE International Superconductive Electronics Conference (ISEC)•Jun 1, 2017•3 citations

Realization of an Opto-Electronic Bias for Pulse-Driven Josephson Voltage Standards at PTB

Jonas Herick, L. Palafox, Eivind Bardalen +5 more

Pulse-driven Josephson voltage standards are used to generate quantum-based, spectrally pure AC voltage signals. The current pulses that drive the Josephson arrays can be transmitted optically and recent progress has demonstrated the operation of fast photodiodes at 4 K. In order to generate bipolar waveforms, two photodiodes are required to generate positive and negative pulses close to the Josephson array. We describe our optoelectronic setup and will present first results on a ternary pulse drive at the conference.

Conference on Precision Electromagnetic Measurements•Aug 1, 2020•8 citations

Biasing Josephson Junctions with Optoelectronically Generated Pulses

Jonathan M. J. Williams, L. Palafox, David A. Humphreys +1 more

A new way of biasing an array of Josephson junctions using optoelectronically generated pulses is described. This method facilitates the generation of positive and negative electrical pulses needed for bipolar waveform synthesis and provides an easy way of optimising the array bias using variable optical attenuators

Conference on Precision Electromagnetic Measurements•Jun 1, 2004•6 citations

Parallelization of the optical pulse-drive for AC Josephson voltage standards

Marco Kraus, Oliver Kieler, Ralf Behr +1 more

Abstract We have successfully operated two Josephson junction arrays in parallel with photonically generated current pulses to achieve higher output voltages with our optical pulse drive setup. Passive optical power splitters divide each optical channel at room temperature in order to illuminate multiple cryogenic photodiodes at 4 K , located near the arrays. The balanced photodiode configurations bias the Josephson junctions with ternary current pulses to generate a 1 kHz bipolar sinusoidal voltage with a nominal root mean square amplitude of 85 mV . We determined a spurious free dynamic range and total harmonic distortion of 110.6 dBc and − 105.0 dB from the spectrum of the synthesized signal. Applying an additional dither current to each array individually yielded a quantum locking range of 0.4 mA and 0.6 mA . Furthermore, the quantum locked operation was confirmed to remain stable when the optical output power of the laser diodes and the DC bias of the Mach–Zehnder modulators were varied. A stability measurement of the output amplitude over more than half an hour confirmed sufficiently wide operating margins, further demonstrating a reliable optical Josephson arbitrary waveform synthesizer setup suitable for generating quantum-based waveform with high spectral purity traceable to fundamental constants. To our knowledge, this is the highest amplitude generated with optically driven Josephson junctions so far and the first successful proof of principle for parallelizing the optical pulse drive to achieve higher output voltages in the future.

Measurement Science and Technology•Aug 18, 2025•1 citation
A new method of driving series arrays of non-hysteretic Josephson junctions using optoelectronically generated pulses to synthesize a variable output voltage is described. Electrical pulses from a photodiode are coupled to the array, and the mean output voltage after filtering is proportional to the pulse repetition frequency with fundamental accuracy. Numerical simulations of the behaviour of the Josephson junctions have been carried out, and these results have been verified by experiment. This technique can be easily extended by using two photodiodes with opposite bias polarities in order to synthesize bipolar alternating or direct voltages.
The optoelectronic coupling for a pulse-driven Josephson junction array (JJA) for use as a quantum voltage synthesizer has been designed. This system uses optoelectronic components to drive a group of JJAs in parallel. Since the drive system is electrically isolated from the JJAs, they can be connected in series, leading to a higher output voltage. A thin film circuit, including interdigitated capacitors to couple a photodiode to the JJAs has been designed and tested and shown to meet the design goals.
An array of Josephson junctions (JJs) was driven with photonically generated current pulses to synthesize a high-fidelity 1 kHz bipolar voltage waveform with a quantum-based amplitude that can be directly related to fundamental constants. A photodiode capable of producing high average photocurrent was used to generate large-amplitude current pulses that were ac-coupled to a JJ array. The resulting bipolar current pulses have enabled the first demonstration of quantum-based bipolar waveform synthesis with an optical drive. We measured the quantum locking range with respect to several operating parameters, including 1.2 mA with respect to a dc bias current applied to the array, confirming the robust synthesis of bipolar waveforms.
Quantum-accurate arbitrary voltage waveforms have been generated using electrical pulse driven Josephson junction arrays (JJAs) by several groups [1, 2]. An alternative method is to use optoelectronic components to convert the electrical pulse drive into an optical signal which is subsequently converted by a photodiode into an electrical drive signal connected directly to the JJA. This optoelectronic pulse drive system has several advantages. Due to the electrical isolation between electrical pulse drive and JJA, it is possible to connect several arrays in series without the requirement for complex electrical compensation circuits. This allows larger output voltages to be realized. An optoelectronic drive also offers the ability to easily tune pulse height, via continuous optical attenuation, allowing the drive signal to be tuned to the middle of the JJA constant voltage step giving optimum operation margins. We here present an optoelectronic pulse drive which forms part of a system incorporating a JJA and delta sigma feedback loop [3] for quantum-accurate digitization of arbitrary voltage waveforms. Results showing the generation of quantum-accurate voltages synchronized to the feedback loop master clock are presented.
Pulse-driven Josephson voltage standards are used to generate quantum-based, spectrally pure AC voltage signals. The current pulses that drive the Josephson arrays can be transmitted optically and recent progress has demonstrated the operation of fast photodiodes at 4 K. In order to generate bipolar waveforms, two photodiodes are required to generate positive and negative pulses close to the Josephson array. We describe our optoelectronic setup and will present first results on a ternary pulse drive at the conference.
Abstract We have successfully operated two Josephson junction arrays in parallel with photonically generated current pulses to achieve higher output voltages with our optical pulse drive setup. Passive optical power splitters divide each optical channel at room temperature in order to illuminate multiple cryogenic photodiodes at 4 K , located near the arrays. The balanced photodiode configurations bias the Josephson junctions with ternary current pulses to generate a 1 kHz bipolar sinusoidal voltage with a nominal root mean square amplitude of 85 mV . We determined a spurious free dynamic range and total harmonic distortion of 110.6 dBc and − 105.0 dB from the spectrum of the synthesized signal. Applying an additional dither current to each array individually yielded a quantum locking range of 0.4 mA and 0.6 mA . Furthermore, the quantum locked operation was confirmed to remain stable when the optical output power of the laser diodes and the DC bias of the Mach–Zehnder modulators were varied. A stability measurement of the output amplitude over more than half an hour confirmed sufficiently wide operating margins, further demonstrating a reliable optical Josephson arbitrary waveform synthesizer setup suitable for generating quantum-based waveform with high spectral purity traceable to fundamental constants. To our knowledge, this is the highest amplitude generated with optically driven Josephson junctions so far and the first successful proof of principle for parallelizing the optical pulse drive to achieve higher output voltages in the future.