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

HTS Josephson heterodyne oscillator on a pulse-tube cryocooler

Jia Du, J.C. Macfarlane, S H K Lam, Richard Taylor

Published Sep 16, 2009• 20 citations
Publisher

Abstract

A high-temperature superconducting (HTS) Josephson heterodyne oscillator based on step-edge junction technology has recently been developed (Du et al 2008 Appl. Phys. Lett. 93 033507, Macfarlane et al 2009 IEEE Trans. Appl. Supercond. 19 920). In this work, the implementation and characterization of such a heterodyne oscillator on a compact pulse-tube cryocooler (PTC) are presented. The rf performance of the oscillator cooled by the cryocooler is compared to that of the same device when cooled in the quiet gas phase of a liquid helium Dewar. Any measurable influence of additional electromagnetic noise and mechanical vibration of the cryocooler on the oscillator performance is assessed by measuring the linewidth broadening of the heterodyne oscillation. The cryocooled oscillator demonstrated excellent performance and negligible excess noise was observed when operating the PTC.

DOI
10.1088/0953-2048/22/10/105013

Related papers

A high-temperature superconducting millimeter wave detecting system based on pulse tube cryocooler

Jian Chen, Peiheng Wu, Kensuke Nakajima +1 more

A millimeter (mm) wave broadband video detecting system using high temperature superconducting (HTS) junction and compact pulse tube cryocooler (PTC) has been studied. The lowest attainable temperature of the PTC is 42K and the operating temperature (T) can be adjusted by changing the pressure difference in the compressor. By measuring the linewidth of the Josephson oscillation as well as the dynamic range of the Josephson detector, it is found that the PTC has no excess noise compared with other kinds of cryostats such as liquid helium cryostats, and is very suitable for the applications in the mm wave detecting system. Furthermore, to improve the sensitivity of the system, the coupling efficiency of the system has been studied in detail. It is found that the coupling efficiency increases with the increase of RN linearly, and is better than 1% for RN of 1.7 Ohm. A sensitivity of about 318V/W has been obtained for the system based on the PTC and a junction with RN=1.7 Ohm and ICRN =1mV.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Oct 8, 2004•0 citations

A Millimeter Wave Detecting System Based on High Temperature Superconducting Device and Pulse Tube Cryocooler

J. Chen, Pan Wu, N. Ebisawa +2 more

A millimeter (mm) wave broadband video detecting system based on high temperature superconducting (HTS) junction and compact pulse tube cryocooler (PTC) has been studied. The lowest attainable temperature of the PTC is 42K and the operating temperature (T) can be adjusted by changing the pressure difference in the compressor. By measuring the linewidth of the Josephson oscillation as well as the dynamic range of the Josephson detector, it is found that the PTC has no excess noise compared with other kinds of cryostats such as liquid helium cryostats, and is very suitable for the applications in the mm wave detecting system. Furthermore, to improve the sensitivity of the system, the coupling efficiency of the system has been studied in detail. It is found that the coupling efficiency increases with the increase of RN linearly, and is better than 1% for RN of 1.7 Ω . A sensitivity of about 318 V/W has been obtained for the system based on the PTC and a junction with RN=1.7 Ω and ICRN = 1mV.

Chinese Journal of Physics•Aug 1, 2004•0 citations

A self-pumped high-temperature superconducting Josephson mixer: Modelling and measurement

Jia Du, J.C. Macfarlane, Colin M. Pegrum +3 more

We have recently developed a high-temperature superconducting (HTS) Josephson self-pumped mixer with an on-chip heterodyne local oscillator. The device is based on HTS step-edge junction technology and a “resistive-superconducting quantum interference device” (RSQUID) configuration. The heterodyne local oscillator and mixer output are frequency-tunable from below 10 MHz to 5 GHz by a control current. The performance of the autonomous Josephson mixer–local oscillator has been experimentally evaluated in terms of the current-voltage characteristics, intermediate frequency (IF)-tunable bandwidth, operation range, linearity, bias current, and temperature dependence of the IF output (or mixer conversion efficiency). We find the results are in good overall agreement with numerical simulation.

Journal of Applied Physics•Mar 1, 2012•10 citations

Simulation and Measurement of HTS Josephson Heterodyne Oscillator

J.C. Macfarlane, Jia Du, Richard Taylor +1 more

We report continuing investigations into practical applications of the AC Josephson effect as the basis for a voltage-tunable radio-frequency oscillator. We have previously demonstrated experimentally that useful power levels (10 s of nW) and linewidths of a few kHz can be achieved in the heterodyne output from a high-temperature-superconducting resistive SQUID (HTS-RSQUID) operating in the frequency range 1-50 MHz. Those results were achieved with 2-junction R-SQUIDs incorporating current-biased shunt resistors of a few micro-ohms. We have now modified the fabrication procedures, and adjusted the shunt resistors and bias current values so that higher frequencies can be achieved. The Josephson junctions are of step-edge type, rather than the bi-crystal type used in our earlier work. The step-edge technique permits much more flexibility in the geometrical lay-out and utilizes the more cost-effective single-crystal MgO substrates. In the present paper, we report numerical simulations and experimental measurements on these devices in the frequency range up to 2 GHz.

IEEE Transactions on Applied Superconductivity•Jun 1, 2009•17 citations

Linewidth of a resistively shunted high-temperature-superconductor Josephson heterodyne oscillator

J.C. Macfarlane, L. Hao, D.A. Peden +1 more

High-temperature-superconducting (HTS) resistively shunted superconducting quantum interference devices, consisting of two yttrium–barium–copper–oxide (YBCO) grain boundary junctions shunted by gold-film resistors of ∼20 μΩ, have been prepared and characterized at temperatures from 17 to 74 K. The small value and stability of the resistor allows narrow-band heterodyne oscillations to be generated between the Josephson oscillations in the individual junctions. The frequency can be precisely controlled in accordance with the ac Josephson effect by adjustment of an external current applied to the YBCO–Au–YBCO shunt resistor, and the linewidth is determined in principle only by Johnson noise in the resistor. Off-chip detection and spectral analysis of the heterodyne signal generated in this way has not been previously reported. Measurements of the signal power (∼nW), the tunability of the center frequency from 5 to 50 MHz, the frequency stability and the linewidth of the heterodyne Josephson oscillation are described. Although linewidth broadening due to nonthermal fluctuations is observed, the linewidth of ∼30 kHz at T=17 K, at a center frequency of 24 MHz, is believed to be the narrowest reported for Josephson oscillations in an HTS device of this type.

Applied Physics Letters•Mar 27, 2000•14 citations

Dynamic Range of High Temperature Superconducting Josephson Detecting Systems at Millimeter-Wave Band

J. Chen, P. Wu, Kiyotaka Nakajima +1 more

YBCO grain boundary Josephson junctions (GBJJ's), with the normal-state resistance (R/sub N/) around 1 /spl Omega/ and I/sub C/R/sub N/ product of less than 2 mV at 45 K, where I/sub C/ is the critical current of the junction, are used to study the dynamic range of high temperature superconducting (HTS) Josephson detecting systems at millimeter-wave band. A compact pulse tube cryocooler (PTC), or a liquid helium cryostat (LHC), or a liquid nitrogen cryostat (LNC) provides the necessary low temperature environment for the operation, while Gunn oscillators together with doubler generate signals at the frequencies of 50, 98, 196 GHz whose amplitude can be adjusted by a series of calibrated attenuators. By changing the junction parameters, operating frequencies, and the cryocooler or cryostat, we have carefully looked at the dynamic range of the system. For a measuring channel bandwidth of 1 Hz, the dynamic range is around 38 dB which is determined basically by the preamplifier. This indicates that the PTC does not introduce excess noise compared with other kinds of cryostats such as LHC's or LNC's. A measuring channel bandwidth up to 1 MHz can be helpful if fast measurements are needed.

IEEE Transactions on Applied Superconductivity•Jun 1, 2005•6 citations
A high-temperature superconducting (HTS) Josephson heterodyne oscillator based on step-edge junction technology has recently been developed (Du et al 2008 Appl. Phys. Lett. 93 033507, Macfarlane et al 2009 IEEE Trans. Appl. Supercond. 19 920). In this work, the implementation and characterization of such a heterodyne oscillator on a compact pulse-tube cryocooler (PTC) are presented. The rf performance of the oscillator cooled by the cryocooler is compared to that of the same device when cooled in the quiet gas phase of a liquid helium Dewar. Any measurable influence of additional electromagnetic noise and mechanical vibration of the cryocooler on the oscillator performance is assessed by measuring the linewidth broadening of the heterodyne oscillation. The cryocooled oscillator demonstrated excellent performance and negligible excess noise was observed when operating the PTC.
A millimeter (mm) wave broadband video detecting system using high temperature superconducting (HTS) junction and compact pulse tube cryocooler (PTC) has been studied. The lowest attainable temperature of the PTC is 42K and the operating temperature (T) can be adjusted by changing the pressure difference in the compressor. By measuring the linewidth of the Josephson oscillation as well as the dynamic range of the Josephson detector, it is found that the PTC has no excess noise compared with other kinds of cryostats such as liquid helium cryostats, and is very suitable for the applications in the mm wave detecting system. Furthermore, to improve the sensitivity of the system, the coupling efficiency of the system has been studied in detail. It is found that the coupling efficiency increases with the increase of RN linearly, and is better than 1% for RN of 1.7 Ohm. A sensitivity of about 318V/W has been obtained for the system based on the PTC and a junction with RN=1.7 Ohm and ICRN =1mV.
A millimeter (mm) wave broadband video detecting system based on high temperature superconducting (HTS) junction and compact pulse tube cryocooler (PTC) has been studied. The lowest attainable temperature of the PTC is 42K and the operating temperature (T) can be adjusted by changing the pressure difference in the compressor. By measuring the linewidth of the Josephson oscillation as well as the dynamic range of the Josephson detector, it is found that the PTC has no excess noise compared with other kinds of cryostats such as liquid helium cryostats, and is very suitable for the applications in the mm wave detecting system. Furthermore, to improve the sensitivity of the system, the coupling efficiency of the system has been studied in detail. It is found that the coupling efficiency increases with the increase of RN linearly, and is better than 1% for RN of 1.7 Ω . A sensitivity of about 318 V/W has been obtained for the system based on the PTC and a junction with RN=1.7 Ω and ICRN = 1mV.
We have recently developed a high-temperature superconducting (HTS) Josephson self-pumped mixer with an on-chip heterodyne local oscillator. The device is based on HTS step-edge junction technology and a “resistive-superconducting quantum interference device” (RSQUID) configuration. The heterodyne local oscillator and mixer output are frequency-tunable from below 10 MHz to 5 GHz by a control current. The performance of the autonomous Josephson mixer–local oscillator has been experimentally evaluated in terms of the current-voltage characteristics, intermediate frequency (IF)-tunable bandwidth, operation range, linearity, bias current, and temperature dependence of the IF output (or mixer conversion efficiency). We find the results are in good overall agreement with numerical simulation.
We report continuing investigations into practical applications of the AC Josephson effect as the basis for a voltage-tunable radio-frequency oscillator. We have previously demonstrated experimentally that useful power levels (10 s of nW) and linewidths of a few kHz can be achieved in the heterodyne output from a high-temperature-superconducting resistive SQUID (HTS-RSQUID) operating in the frequency range 1-50 MHz. Those results were achieved with 2-junction R-SQUIDs incorporating current-biased shunt resistors of a few micro-ohms. We have now modified the fabrication procedures, and adjusted the shunt resistors and bias current values so that higher frequencies can be achieved. The Josephson junctions are of step-edge type, rather than the bi-crystal type used in our earlier work. The step-edge technique permits much more flexibility in the geometrical lay-out and utilizes the more cost-effective single-crystal MgO substrates. In the present paper, we report numerical simulations and experimental measurements on these devices in the frequency range up to 2 GHz.
High-temperature-superconducting (HTS) resistively shunted superconducting quantum interference devices, consisting of two yttrium–barium–copper–oxide (YBCO) grain boundary junctions shunted by gold-film resistors of ∼20 μΩ, have been prepared and characterized at temperatures from 17 to 74 K. The small value and stability of the resistor allows narrow-band heterodyne oscillations to be generated between the Josephson oscillations in the individual junctions. The frequency can be precisely controlled in accordance with the ac Josephson effect by adjustment of an external current applied to the YBCO–Au–YBCO shunt resistor, and the linewidth is determined in principle only by Johnson noise in the resistor. Off-chip detection and spectral analysis of the heterodyne signal generated in this way has not been previously reported. Measurements of the signal power (∼nW), the tunability of the center frequency from 5 to 50 MHz, the frequency stability and the linewidth of the heterodyne Josephson oscillation are described. Although linewidth broadening due to nonthermal fluctuations is observed, the linewidth of ∼30 kHz at T=17 K, at a center frequency of 24 MHz, is believed to be the narrowest reported for Josephson oscillations in an HTS device of this type.
YBCO grain boundary Josephson junctions (GBJJ's), with the normal-state resistance (R/sub N/) around 1 /spl Omega/ and I/sub C/R/sub N/ product of less than 2 mV at 45 K, where I/sub C/ is the critical current of the junction, are used to study the dynamic range of high temperature superconducting (HTS) Josephson detecting systems at millimeter-wave band. A compact pulse tube cryocooler (PTC), or a liquid helium cryostat (LHC), or a liquid nitrogen cryostat (LNC) provides the necessary low temperature environment for the operation, while Gunn oscillators together with doubler generate signals at the frequencies of 50, 98, 196 GHz whose amplitude can be adjusted by a series of calibrated attenuators. By changing the junction parameters, operating frequencies, and the cryocooler or cryostat, we have carefully looked at the dynamic range of the system. For a measuring channel bandwidth of 1 Hz, the dynamic range is around 38 dB which is determined basically by the preamplifier. This indicates that the PTC does not introduce excess noise compared with other kinds of cryostats such as LHC's or LNC's. A measuring channel bandwidth up to 1 MHz can be helpful if fast measurements are needed.