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

Experiments on Coupled Josephson Junction Devices

A. A. Abdumalikov, Alexey Vladimirovich Ustinov

Published Jul 15, 2003• 0 citations
OpenAlex

Abstract

This report results from a contract tasking University of Erlangen-Nuremberg as follows: The contractor will investigate coupled Josephson devices of two different kinds. First, the contractor will test a new concept of active antennas to couple radiation out from Josephson arrays. Using a mixed series-parallel array-biasing scheme, the contractor will design and perform waveguide-coupled emission experiments with single- and double-row arrays at 80-120 GHz. If successful, this scheme will be further implemented and tested using dipole antennas for the 400-500 GHz range. The contractor will also investigate the loop antenna array scheme as detailed in the technical proposal. The experiments will be done with Nb/Al- AOx/Nb Josephson junction arrays. The second Josephson device to be investigated (including design, fabrication, and testing) are novel q-bit devices. These q-bits are hoped to be more flexible and therefore more suitable hardware for quantum computing than single- loop SQUIDs currently pursued by other researcher groups. Full details are provided in the accompaning technical proposal.

Related papers

Experimental Study of Josephson Qubits and Oscillators

Jürgen Lisenfeld, A. A. Abdumalikov, Alexey Vladimirovich Ustinov

This report results from a contract tasking University of Erlangen-Nuremberg as follows: The Grantee will investigate physical properties and improve the performance of two groups of Josephson devices: Josephson junction array oscillators and Josephson Qubits. They will continue study of series-parallel Josephson junction array oscillators from earlier research. The goal is to significantly increase the detected radiated power from 80 GHz to 120 GHz by improving the resonance frequency match between the devices and the receiver. They will also test the compact arrays of similar oscillator devices which incorporate antenna wires. Second, they will design and fabricate Josephson qubit devices for characterization from 4.2 K down to 20 mK. The energy profile will be characterized in the classical regime and projected into the quantum range and the coupling of the qubits to the environment will be examined according to the approach detailed in the technical proposal.

•Jul 1, 2004•0 citations

Testing of Josephson Array Antennas and Trim Current Tuning

A. A. Abdumalikov, P. Caputo, Alexey Vladimirovich Ustinov

This report results from a contract tasking University of Erlangen-Nuremberg as follows: contractor will investigate novel designs of triangular Josephson Junction arrays attempting to improve the high-frequency performance of the arrays in two ways; first, increase the operation frequencies and second, increase the output power of the millimeter-band radiation to level enabling practical application of the arrays. Three approaches will be investigated. First, trimming of currents at the array edges is expected to stabilize coherent oscillations and increase the operation margins (output power). Second, it appears promising to set up a traveling wave in a transmission line that contains an array comparable with the wavelength. Third, testing dipole-like active antennas to couple radiation out from arrays is a high priority task for emission in free space at high frequencies. The contractor will experimentally verify the above concepts by designing new circuits and performing experiments with Nb/AOx/Nb Josephson Junction arrays. For these experiments, the contractor will use a millimeter-wave band receiver as well an on-chip detection circuits up to 300 GHz. Spatially-resolved measurements using low temperature scanning laser microscopy will be performed in order to monitor array dynamics at the junction level. Furthermore, the contractor intends to design a dipole antenna and test it with an integrated receiver in 400-500 GHz frequency range. For this purpose, improvements for a flux-flow oscillator as a local oscillator may be needed. Finally, the contractor will perform experiments with shunted junction arrays in order to simulate intrinsically overdamped high-Tc junctions and explore a possibility of using high Tc layered junctions for oscillator application

•Sep 1, 2002•0 citations

Submillimeter Quasioptical Josephson Junction Oscillator with Integrated Tuning Elements

A. Pance, Andrew T. Barfknecht

The goal of this program was to demonstrate a Quasioptical Josephson Oscillator with Integrated Tuning Elements using standard Conductus niobium technology. This device is based on a novel approach that incorporates integrated tuning and impedance-matching structures at every Josephson junction/ antenna pair. The device has been designed, fabricated and successfully tested. A new, unit cell has been devised, incorporating a sub-array of 1 to 16 Josephson junctions. Microstrip transformers are used locally between each sub- array and its antenna. The oscillator with 110 Josephson junctions and bow-tie antennas was found to radiate close to its maximum available power at 115 GHz. The on-chip SIS radiation detector has detected 2.64 nW of power. The oscillator was tuned across 19 GHz, or 16% of fractional bandwidth, in reasonable agreement with the predicted value of 19%. This is the first demonstration of a distributed array Josephson oscillator, where each junction feeds its own antenna and phase-locks to the radiation of other junctions. It is also the first demonstration of using integrated microstrip tuning and impedance matching elements at every Josephson junction of an oscillator. Finally, this is the first distributed Josephson oscillator reported to date that appears to radiate close to its maximum available power. Submillimeter, Oscillators, Antenna arrays, Superconducting electronics, Quasioptical.

Final Report•Apr 30, 1994•0 citations

Applications of Josephson Junction SQUIDs and Arrays.

Arnold H. Silver

This is a new contract for a projected multi-year investigation of Superconducting Quantum Interference Device (SQUID) arrays and their application to microwave technology. The focus of this contract is the investigation and demonstration of a SQUID voltage-controlled oscillator (VCO). The array is then projected to increase the available power and operating impedance. The approach adopted will utilize monolithic superconducting integrated circuits which will be designed, fabricated, and tested at TRW. The project has three tasks: (1) Analysis of dc SQUID Arrays; (2) Design of dc SQUID Generator; and (3) SQUID VCO Fabrication and Measurement which are being carried out.

Quarterly Report•Jan 15, 1982•0 citations

High Transition Temperature Quantum Interference Filters

Shane A. Cybart, R. C. Dynes

Abstract : We have fabricated and tested large scale arrays of Josephson junctions. Some devices have as many as 150,000 junctions in a single device. To aid in device design we have also developed a numerical simulation program in Matlab to simulate voltage magnetic field characteristics for these arrays. Our numerical simulation code supports the modeling of 2 dimensional array structures and takes into account mutual interactions between all of the squids in the array. The results are in excellent agreement with our experimental measurements. We have also performed measurements of the critical current noise in our Josephson junctions and have been testing arrays in flux locked loops.

•Nov 28, 2011•0 citations

A new 10-V array of Josephson junctions based on low-frequency designs scaled up to 94 GHz

Hiroyuki Yoshida, Y. Murayama, T. Endo

A novel approach is described for the design of improved coupling of millimeter-waves in a 10-V array of Josephson junctions. In this approach, microwave structures were fabricated and tested in the range 2.8 GHz to 3.6 GHz, and a scaling calculation was then used to transform them to 94 GHz. By optimizing the trade-off between antenna size and efficiency, it was possible to make more space available on the device chip to increase the number of Josephson junctions. Simulation results showed that the optimal antenna is a short double-fin-line type. This antenna type allowed us to fabricate a Josephson junction array that had 25944 Nb/Al-AlO/sub x//Nb junctions. For this new array, zero-crossing steps were observed up to 18.5 V. The new array was then successfully used to calibrate a Zener voltage standard that had a 10-V output.

IEEE Transactions on Instrumentation and Measurement•Jan 1, 1997•4 citations
This report results from a contract tasking University of Erlangen-Nuremberg as follows: The contractor will investigate coupled Josephson devices of two different kinds. First, the contractor will test a new concept of active antennas to couple radiation out from Josephson arrays. Using a mixed series-parallel array-biasing scheme, the contractor will design and perform waveguide-coupled emission experiments with single- and double-row arrays at 80-120 GHz. If successful, this scheme will be further implemented and tested using dipole antennas for the 400-500 GHz range. The contractor will also investigate the loop antenna array scheme as detailed in the technical proposal. The experiments will be done with Nb/Al- AOx/Nb Josephson junction arrays. The second Josephson device to be investigated (including design, fabrication, and testing) are novel q-bit devices. These q-bits are hoped to be more flexible and therefore more suitable hardware for quantum computing than single- loop SQUIDs currently pursued by other researcher groups. Full details are provided in the accompaning technical proposal.
This report results from a contract tasking University of Erlangen-Nuremberg as follows: The Grantee will investigate physical properties and improve the performance of two groups of Josephson devices: Josephson junction array oscillators and Josephson Qubits. They will continue study of series-parallel Josephson junction array oscillators from earlier research. The goal is to significantly increase the detected radiated power from 80 GHz to 120 GHz by improving the resonance frequency match between the devices and the receiver. They will also test the compact arrays of similar oscillator devices which incorporate antenna wires. Second, they will design and fabricate Josephson qubit devices for characterization from 4.2 K down to 20 mK. The energy profile will be characterized in the classical regime and projected into the quantum range and the coupling of the qubits to the environment will be examined according to the approach detailed in the technical proposal.
This report results from a contract tasking University of Erlangen-Nuremberg as follows: contractor will investigate novel designs of triangular Josephson Junction arrays attempting to improve the high-frequency performance of the arrays in two ways; first, increase the operation frequencies and second, increase the output power of the millimeter-band radiation to level enabling practical application of the arrays. Three approaches will be investigated. First, trimming of currents at the array edges is expected to stabilize coherent oscillations and increase the operation margins (output power). Second, it appears promising to set up a traveling wave in a transmission line that contains an array comparable with the wavelength. Third, testing dipole-like active antennas to couple radiation out from arrays is a high priority task for emission in free space at high frequencies. The contractor will experimentally verify the above concepts by designing new circuits and performing experiments with Nb/AOx/Nb Josephson Junction arrays. For these experiments, the contractor will use a millimeter-wave band receiver as well an on-chip detection circuits up to 300 GHz. Spatially-resolved measurements using low temperature scanning laser microscopy will be performed in order to monitor array dynamics at the junction level. Furthermore, the contractor intends to design a dipole antenna and test it with an integrated receiver in 400-500 GHz frequency range. For this purpose, improvements for a flux-flow oscillator as a local oscillator may be needed. Finally, the contractor will perform experiments with shunted junction arrays in order to simulate intrinsically overdamped high-Tc junctions and explore a possibility of using high Tc layered junctions for oscillator application
The goal of this program was to demonstrate a Quasioptical Josephson Oscillator with Integrated Tuning Elements using standard Conductus niobium technology. This device is based on a novel approach that incorporates integrated tuning and impedance-matching structures at every Josephson junction/ antenna pair. The device has been designed, fabricated and successfully tested. A new, unit cell has been devised, incorporating a sub-array of 1 to 16 Josephson junctions. Microstrip transformers are used locally between each sub- array and its antenna. The oscillator with 110 Josephson junctions and bow-tie antennas was found to radiate close to its maximum available power at 115 GHz. The on-chip SIS radiation detector has detected 2.64 nW of power. The oscillator was tuned across 19 GHz, or 16% of fractional bandwidth, in reasonable agreement with the predicted value of 19%. This is the first demonstration of a distributed array Josephson oscillator, where each junction feeds its own antenna and phase-locks to the radiation of other junctions. It is also the first demonstration of using integrated microstrip tuning and impedance matching elements at every Josephson junction of an oscillator. Finally, this is the first distributed Josephson oscillator reported to date that appears to radiate close to its maximum available power. Submillimeter, Oscillators, Antenna arrays, Superconducting electronics, Quasioptical.
This is a new contract for a projected multi-year investigation of Superconducting Quantum Interference Device (SQUID) arrays and their application to microwave technology. The focus of this contract is the investigation and demonstration of a SQUID voltage-controlled oscillator (VCO). The array is then projected to increase the available power and operating impedance. The approach adopted will utilize monolithic superconducting integrated circuits which will be designed, fabricated, and tested at TRW. The project has three tasks: (1) Analysis of dc SQUID Arrays; (2) Design of dc SQUID Generator; and (3) SQUID VCO Fabrication and Measurement which are being carried out.
Abstract : We have fabricated and tested large scale arrays of Josephson junctions. Some devices have as many as 150,000 junctions in a single device. To aid in device design we have also developed a numerical simulation program in Matlab to simulate voltage magnetic field characteristics for these arrays. Our numerical simulation code supports the modeling of 2 dimensional array structures and takes into account mutual interactions between all of the squids in the array. The results are in excellent agreement with our experimental measurements. We have also performed measurements of the critical current noise in our Josephson junctions and have been testing arrays in flux locked loops.
A novel approach is described for the design of improved coupling of millimeter-waves in a 10-V array of Josephson junctions. In this approach, microwave structures were fabricated and tested in the range 2.8 GHz to 3.6 GHz, and a scaling calculation was then used to transform them to 94 GHz. By optimizing the trade-off between antenna size and efficiency, it was possible to make more space available on the device chip to increase the number of Josephson junctions. Simulation results showed that the optimal antenna is a short double-fin-line type. This antenna type allowed us to fabricate a Josephson junction array that had 25944 Nb/Al-AlO/sub x//Nb junctions. For this new array, zero-crossing steps were observed up to 18.5 V. The new array was then successfully used to calibrate a Zener voltage standard that had a 10-V output.