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Search Publications by: Pete Hopkins (Fed)

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Displaying 26 - 50 of 56

A Cryogenic Quantum-Based RF Source

September 10, 2020
Author(s)
Justus A. Brevik, Alirio De Jesus Soares Boaventura, Manuel C. Castellanos Beltran, Christine A. Donnelly, Nathan E. Flowers-Jacobs, Anna E. Fox, Peter F. Hopkins, Paul D. Dresselhaus, Dylan Williams, Samuel P. Benz
We performed a preliminary calibrated measurement of the output power of a Josephson arbitrary waveform synthesizer up to 1 GHz. We present the results and measurement procedure for generating quantum-based signals using an array of Josephson junctions

Microwave Modeling and Characterization of Superconductive Circuits for Quantum Voltage Standard Applications at 4 Kelvin

February 10, 2020
Author(s)
Alirio De Jesus Soares Boaventura, Dylan F. Williams, Richard A. Chamberlin, Jerome G. Cheron, Anna E. Fox, Paul D. Dresselhaus, Peter F. Hopkins, Ian W. Haygood, Samuel P. Benz
We developed a cryogenic multiline thru-reflect-line (TRL) calibration kit for microwave characterizing of superconductive circuits used in the Josephson arbitrary waveform synthesizer of the national institute of standards and technology (NIST). We also

Synaptic weighting in single flux quantum neuromorphic computing

January 22, 2020
Author(s)
Michael L. Schneider, Christine A. Donnelly, Ian W. Haygood, Alex Wynn, Stephen E. Russek, Manuel C. Castellanos Beltran, Paul D. Dresselhaus, Peter F. Hopkins, Matthew R. Pufall, William H. Rippard
Josephson junctions act as a natural spiking neuron-like device for neuromorphic computing. By leveraging the advances recently demonstrated in digital single flux quantum (SFQ) circuits and using recently demonstrated magnetic Josephson junction (MJJ)

1 GHz Waveform Synthesis with Josephson Arrays

July 31, 2019
Author(s)
Christine A. Donnelly, Justus A. Brevik, Nathan E. Flowers-Jacobs, Peter F. Hopkins, Paul D. Dresselhaus, Samuel P. Benz
For the first time, we synthesize single- and multiple-tone waveforms at gigahertz frequencies from arrays of Josephson junctions and demonstrate quantum-locked operation over a range of experimental input parameters. We first use a lumped-element circuit

1 GHz Waveform Synthesis With Josephson Junction Arrays

July 31, 2019
Author(s)
Christine A. Donnelly, Nathan E. Flowers-Jacobs, Justus A. Brevik, Anna E. Fox, Paul D. Dresselhaus, Peter F. Hopkins, Samuel P. Benz
We synthesize single- and multiple-tone waveforms at gigahertz frequencies from arrays of Josephson junctions and demonstrate their quantum-locked operation over a range of experimental input parameters. We first use a lumped-element circuit to synthesize

Quantized Pulse Propagation in Josephson Junction Arrays

July 23, 2019
Author(s)
Christine A. Donnelly, Justus Brevik, Nathan Flowers-Jacobs, Anna Fox, Paul Dresselhaus, Peter F. Hopkins, Samuel Benz
We present time-domain electrical measurements and simulations of the quantized voltage pulses that are generated from series-connected Josephson junction (JJ) arrays. The transmission delay of the JJ array can lead to a broadening of the net output pulse

Planarized process for single-flux-quantum circuits with self-shunted Nb/NbxSi1-x/Nb Josephson junctions

February 18, 2019
Author(s)
David I. Olaya, Manuel C. Castellanos Beltran, Javier Pulecio, John P. Biesecker, Soroush Khadem, Theodore Lewitt, Peter F. Hopkins, Paul D. Dresselhaus, Samuel P. Benz
We describe the single-flux-quantum (SFQ) circuit fabrication process employed at NIST's Boulder Microfabrication Facility. The process includes four superconducting metal layers, one palladium-gold resistor layer, and a contact pad layer. Chemical

RF waveform synthesizers with quantum-based voltage accuracy for communications metrology

February 11, 2019
Author(s)
Peter F. Hopkins, Justus A. Brevik, Manuel C. Castellanos Beltran, Nathan E. Flowers-Jacobs, Anna E. Fox, David I. Olaya, Christine A. Donnelly, Paul D. Dresselhaus, Samuel P. Benz
We report on NIST’s development of Josephson junction-based programmable reference sources to synthesize quantum-accurate, spectrally-pure waveforms for characterizing and improving next generation communication devices and systems. The goal is to provide

Stacked Josephson Junctions as inductors for SFQ circuits

February 11, 2019
Author(s)
Manuel C. Castellanos Beltran, David I. Olaya, Adam J. Sirois, Paul D. Dresselhaus, Samuel P. Benz, Peter F. Hopkins
In order for Single Flux Quantum (SFQ) circuits to be scaled to densities needed for large-scale integration, typical lithographically-patterned circuit components should be made to be as compact as possible. In this work, we characterize the performance

Energy efficient single flux quantum based neuromorphic computing

November 8, 2018
Author(s)
Michael Schneider, Christine A. Donnelly, Stephen E. Russek, Burm Baek, Matthew Pufall, Pete Hopkins, William Rippard
Many neuromorphic hardware technologies are being explored for their potential to increase the efficiency of computing certain problems, and thus facilitate machine learning with greater energy efficiency and or with more complexity. Among the technologies

Jitter Sensitivity Analysis of the Superconducting Josephson Arbitrary Waveform Synthesizer

November 4, 2018
Author(s)
Christine A. Donnelly, Justus Brevik, Paul Dresselhaus, Pete Hopkins, Samuel P. Benz
We present the first jitter sensitivity analysis of a superconducting voltage reference waveform synthesizer with fundamentally accurate output pulses. Successful deployment of a reference waveform source at microwave frequencies will represent a new

Radiofrequency Waveform Synthesis with the Josephson Arbitrary Waveform Synthesizer

July 7, 2018
Author(s)
Justus Brevik, Christine A. Donnelly, Nathan Flowers-Jacobs, Anna Fox, Pete Hopkins, Paul Dresselhaus, Samuel P. Benz
We have measured the frequency-dependent voltage output up to 100 MHz of a modified version of the Josephson Arbitrary Waveform Synthesizer. An impedance-matching resistor was integrated within the Josephson junction array circuit to match the nominally

Ultralow power artificial synapses using nanotextured magnetic Josephson junctions

January 28, 2018
Author(s)
Michael L. Schneider, Christine A. Donnelly, Stephen E. Russek, Burm Baek, Matthew R. Pufall, Peter F. Hopkins, Paul D. Dresselhaus, Samuel P. Benz, William H. Rippard
Neuromorphic computing is a promising avenue to dramatically improve the efficiency of certain computational tasks, such as perception and decision making. Neuromorphic systems are currently being developed for critical applications ranging from self