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

Journal of Applied Physics

Influence of microwave phase noise on Josephson voltage steps

Gian Paolo Bava, Domenico Andreone, E. Bava, A. Godone

Published Sep 1, 1982• 4 citations
Publisher

Abstract

The influence of microwave phase noise on rf-induced constant voltage steps generated by the ac Josephson effect is studied. Different circuit models for the junction excitation are considered: dc and rf voltage generators, dc and rf current generators, dc current and rf voltage generators. The analysis has been carried out assuming a power and band limited phase noise modulation in the first two cases, while in the last one a white frequency modulation spectrum is required for a treatment based on the Fokker-Planck equation. Some experimental results are reported, in order to display the basic phenomenological behavior.

DOI
10.1063/1.331500

Related papers

Capacitance measurement of Josephson tunnel junctions with microwave-induced dc quasiparticle tunneling currents

K. Hamasaki, Keiji Yoshida, F. Irie +1 more

The microwave response of the dc quasiparticle tunneling current in Josephson tunnel junctions, where the Josephson current is suppressed by an external magnetic field, has been studied quantitatively in order to clarify its characteristics as a probe for the measurement of the junction capacitance. Extensive experiments for both small and long junctions are carried out for distinguishing between microwave behaviors of lumped and distributed constant junctions. It is shown that the observed voltage dependence of the dc quasiparticle tunneling current modified by an applied rf field is in good agreement with a theoretical result which takes into account the influence of the microwave circuit connected to the junction. The comparison between theory and experiment gives the magnitude of the internal rf field in the junction. Together with the applied rf field, this internal rf field leads to the junction rf impedance which is dominated by the junction capacitance in our experimental condition. In the case of lumped junctions, this experimental rf impedance is in reasonable agreement with the theoretical one with the junction capacitance estimated from the Fiske step of the distributed junction fabricated on the same substrate; the obtained ratio of the experimental impedance to the theoretical one is approximately 0.6–1.7. In the case of distributed junctions, however, experimental values of their characteristic impedances are approximately 0.2–0.3 of theoretical values calculated by assuming the one-dimensional junction model and taking account of the standing-wave effect in the junction.

Journal of Applied Physics•May 1, 1982•3 citations

Challenges of Josephson Junction Arrays for ac Voltage Generation by Microwave Pulse Power Modulation

Alexander S. Katkov, Alexander M. Klushin, G. P. Telitchenko +2 more

Voltage pulses with a determined amplitude and width might be the basis for high-precision ac voltage measurements in the future. The pulse width modulation technique makes possible the generation of arbitrary waveforms. In this paper, arrays of SINIS Josephson junctions were investigated which produce a 1 V voltage step under irradiation at a frequency of the order of 70 GHz. This step has an amplitude of 1 mA whereof a region of 0.3 mA overlaps with the critical current. This allows the generation of a 1 V voltage pulse by switching the microwave power at constant dc bias current. The results of this investigation will be presented and also the array parameters which are required for obtaining a relative uncertainty of 0.1 ppm in ac voltage measurements.

IEEE Transactions on Applied Superconductivity•Jun 1, 2005•4 citations

Constant-Voltage Steps in the V-I Curve of a J-J Loop

Sumitaka Takeuchi, Hidemi Narita, Tadayuki Kobayashi +3 more

Both resonant and microwave-induced steps in the V-I characteristics of four-Josephson-junction loop with a small junction-parameter spread have been investigated. An rf current was superimposed onto a dc current and the radio frequency was tuned to the resonance frequency of the loop. In the high-Q region, the rf-power dependence of the step amplitude was similar to that of a single junction. However, we obtained V-I characteristics which indicated that the behavior of the junction in the loop was coherent in the low-Q region.

Japanese Journal of Applied Physics•Dec 1, 1985•2 citations

Microwave-Induced Vortex Motion in Long Josephson Junctions

Katsuyoshi Hamasaki, Keiji Yoshida, Fujio Irie +2 more

Experimental and theoretical studies are made of the effect of a microwave on dc current-voltage characteristics of long Josephson junctions. In the case of zero external dc current, dc voltages were observed when the microwave was applied to the junctions. By comparing the observed magnetic-field and microwave-power dependences with theoretical results, it is concluded that these dc voltages resulted from vortex motion which was induced by the applied microwave. When the junctions were in a flux-flow state caused by the external current, a good agreement between theory and experiment concerning the microwave-power and magnetic-field dependences of Shapiro steps demonstrates that an almost ideal traveling-wave type coupling between the applied microwave and a moving vortex array took place in the long Josephson junctions.

Japanese Journal of Applied Physics•Jan 1, 1980•7 citations

Calculation of the Shapiro step amplitudes in two-dimensional Josephson tunnel junction

U. Klein, S. Schroder, Johann Heyen Hinken

We have investigated theoretically the amplitudes of RF- induced constant voltage steps in two-dimensional Josephson tunnel junctions, using both a first-order approximation and a numerical it- eration procedure to calculate the current density distribution in the junction. We use a planar resonator model to analyze the electromag- netic field in the microwave-driven junction. Integrating the local Jo- sephson current density over the junction area yields the total dc current on a chosen Shapiro step. Numerical calculations of the Sha- piro step amplitudes in two-dimensional resonant junctions show a qualitatively different behavior from that in one-dimensional resonant junctions. Depending on the dominant resonant mode, the microwave power dependence of the step amplitude gives a smooth curve without zeros. This behavior is advantageous for biasing the Josephson junc- tion in its maximum step amplitude. The main difference between the results of the first-order approximation and the full theory is that- using the iteration procedure-the Shapiro steps in resonant junctions become asymmetric with respect to the quasi-particle curve. This is due to consideration of the losses and the internal Josephson currents in the numerical iteration procedure of the full theory.

IEEE Transactions on Instrumentation and Measurement•Apr 1, 1991•4 citations

Noise study of a high-T c Josephson junction under near-millimeter-wave irradiation

R. Gupta, Qing Hu, D. Terpstra +2 more

Noise studies of both the dc and ac Josephson effects have been performed on a high-Tc ramp-type Josephson junction irradiated at 176 GHz. Well-established analytical results for noise in overdamped RSJs are used to model the measured I-V characteristics, and their agreement is excellent. Noise-rounded I-V curves at the critical current and the first and second Shapiro steps under coherent 176 GHz radiation have been studied in detail at several temperatures and rf power levels. The noise temperatures inferred from these simulations are close to the physical temperatures. An increase of noise temperatures at high radiation power levels is a result of radiation heating, which could be due to a bolometric effect.

Applied Physics Letters•Feb 14, 1994•8 citations
The influence of microwave phase noise on rf-induced constant voltage steps generated by the ac Josephson effect is studied. Different circuit models for the junction excitation are considered: dc and rf voltage generators, dc and rf current generators, dc current and rf voltage generators. The analysis has been carried out assuming a power and band limited phase noise modulation in the first two cases, while in the last one a white frequency modulation spectrum is required for a treatment based on the Fokker-Planck equation. Some experimental results are reported, in order to display the basic phenomenological behavior.
The microwave response of the dc quasiparticle tunneling current in Josephson tunnel junctions, where the Josephson current is suppressed by an external magnetic field, has been studied quantitatively in order to clarify its characteristics as a probe for the measurement of the junction capacitance. Extensive experiments for both small and long junctions are carried out for distinguishing between microwave behaviors of lumped and distributed constant junctions. It is shown that the observed voltage dependence of the dc quasiparticle tunneling current modified by an applied rf field is in good agreement with a theoretical result which takes into account the influence of the microwave circuit connected to the junction. The comparison between theory and experiment gives the magnitude of the internal rf field in the junction. Together with the applied rf field, this internal rf field leads to the junction rf impedance which is dominated by the junction capacitance in our experimental condition. In the case of lumped junctions, this experimental rf impedance is in reasonable agreement with the theoretical one with the junction capacitance estimated from the Fiske step of the distributed junction fabricated on the same substrate; the obtained ratio of the experimental impedance to the theoretical one is approximately 0.6–1.7. In the case of distributed junctions, however, experimental values of their characteristic impedances are approximately 0.2–0.3 of theoretical values calculated by assuming the one-dimensional junction model and taking account of the standing-wave effect in the junction.
Voltage pulses with a determined amplitude and width might be the basis for high-precision ac voltage measurements in the future. The pulse width modulation technique makes possible the generation of arbitrary waveforms. In this paper, arrays of SINIS Josephson junctions were investigated which produce a 1 V voltage step under irradiation at a frequency of the order of 70 GHz. This step has an amplitude of 1 mA whereof a region of 0.3 mA overlaps with the critical current. This allows the generation of a 1 V voltage pulse by switching the microwave power at constant dc bias current. The results of this investigation will be presented and also the array parameters which are required for obtaining a relative uncertainty of 0.1 ppm in ac voltage measurements.
Both resonant and microwave-induced steps in the V-I characteristics of four-Josephson-junction loop with a small junction-parameter spread have been investigated. An rf current was superimposed onto a dc current and the radio frequency was tuned to the resonance frequency of the loop. In the high-Q region, the rf-power dependence of the step amplitude was similar to that of a single junction. However, we obtained V-I characteristics which indicated that the behavior of the junction in the loop was coherent in the low-Q region.
Experimental and theoretical studies are made of the effect of a microwave on dc current-voltage characteristics of long Josephson junctions. In the case of zero external dc current, dc voltages were observed when the microwave was applied to the junctions. By comparing the observed magnetic-field and microwave-power dependences with theoretical results, it is concluded that these dc voltages resulted from vortex motion which was induced by the applied microwave. When the junctions were in a flux-flow state caused by the external current, a good agreement between theory and experiment concerning the microwave-power and magnetic-field dependences of Shapiro steps demonstrates that an almost ideal traveling-wave type coupling between the applied microwave and a moving vortex array took place in the long Josephson junctions.
We have investigated theoretically the amplitudes of RF- induced constant voltage steps in two-dimensional Josephson tunnel junctions, using both a first-order approximation and a numerical it- eration procedure to calculate the current density distribution in the junction. We use a planar resonator model to analyze the electromag- netic field in the microwave-driven junction. Integrating the local Jo- sephson current density over the junction area yields the total dc current on a chosen Shapiro step. Numerical calculations of the Sha- piro step amplitudes in two-dimensional resonant junctions show a qualitatively different behavior from that in one-dimensional resonant junctions. Depending on the dominant resonant mode, the microwave power dependence of the step amplitude gives a smooth curve without zeros. This behavior is advantageous for biasing the Josephson junc- tion in its maximum step amplitude. The main difference between the results of the first-order approximation and the full theory is that- using the iteration procedure-the Shapiro steps in resonant junctions become asymmetric with respect to the quasi-particle curve. This is due to consideration of the losses and the internal Josephson currents in the numerical iteration procedure of the full theory.
Noise studies of both the dc and ac Josephson effects have been performed on a high-Tc ramp-type Josephson junction irradiated at 176 GHz. Well-established analytical results for noise in overdamped RSJs are used to model the measured I-V characteristics, and their agreement is excellent. Noise-rounded I-V curves at the critical current and the first and second Shapiro steps under coherent 176 GHz radiation have been studied in detail at several temperatures and rf power levels. The noise temperatures inferred from these simulations are close to the physical temperatures. An increase of noise temperatures at high radiation power levels is a result of radiation heating, which could be due to a bolometric effect.