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A SUPERCONDUCTIVE PARALLEL JUNCTION ARRAY MIXER FOR VERY WIDE BAND HETERODYNE SUBMILLIMETER-WAVE SPECTROMETRY

Faouzi M. Boussaha, Y. Delorme, Morvan C. Salez, M. H. Chung, Frédéric Dauplay, B. Lecomte, Jean-Guy Caputo, V. Thevenet

Published Mar 1, 2002• 0 citations
OpenAlex

Abstract

The study of submillimeter-wave radiation in astronomy and atmospheric sciences requires increasingly performant receivers, in particular allowing extended spectral line surveys. To this end, we are developing a quantum-noise limited heterodyne receiver based on SIS junction parallel arrays with broad (larger than 30%) fixed tuned bandwidth. Simulations show that networks of junctions (N>2) of micronic size, embedded in a superconducting inicrostrip line, can provide a bandwidth in excess of the ultimate limit for a single or even twin junction device. These circuits can be viewed as passband filters which have been optimized by varying the spacings between junctions. The results of simulations are confirmed by the first heterodyne measurements in the 480-650GHz bandwidth, and by preliminary FTS measurements beyond. The influence of the Josephson effect in these devices is also investigated.

Related papers

Submillimeter mixers based on superconductive parallel junction arrays

Faouzi M. Boussaha, Morvan C. Salez, Y. Delorme +4 more

Observation and analysis of submillimeter-wave radiation (300GHz-3THz) in astronomy and atmospheric sciences requires increasingly performant receivers. The most sensitive receivers working in this range of electromagnetic spectrum use superconductor-insolator-superconductor (SIS) junctions. In order to increase the bandwidth and the sensitivity, we are developing a quantum-noise limited heterodyne receiver based on several parallel SIS junctions with broad (larger than 30%) fixed tuned bandwidth. These circuits can be viewed as passband filters which have been optimized by varying the spacings between junctions. We have designed such 5-junction arrays for operation in the range 480-640 GHz. Fabrication and heterodyne characterization of these devices has been done. The 1 μm2 junctions current density ranges from 4 to 13 kA/cm2, using optical lithography and Nb/Al2Nb5/Nb trilayer sputtering technology. The fabrication process and yield are presented in this paper, along with measured performances

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Apr 25, 2003•1 citation

Low-noise THz Niobium SIS Mixers

Mei Bin

This thesis describes the development of low-noise heterodyne receivers at THz frequencies for submillimeter astronomy using Nb-based superconductor-insulator-superconductor (SIS) tunneling junctions. The mixers utilize a quasi-optical configuration which consists of a planar twin-slot antenna and antisymmetrically-fed two-junctions on an antireflection-coated silicon hyperhemispherical lens. On-chip integrated tuning circuits, in the form of microstrip lines, are used to obtain maximum coupling efficiency in the designed frequency band. To reduce the rf losses in the integrated tuning circuits above the superconducting Nb gap frequency (~ 700 GHz), normal-metal Al is used to replace Nb as the tuning circuits. To account the rf losses in the micros trip lines, we calculated the surface impedance of the AI films using the nonlocal anomalous skin effect for finite thickness films. Nb films were calculated using the Mattis-Bardeen theory in the extreme anomalous limit. Our calculations show that the losses of the Al and Nb microstrip lines are about equal at 830 GHz. For Al-wiring and Nb-wiring mixers both optimized at 1050 GHz, the RF coupling efficiency of Al-wiring mixer is higher than that of Nb-wiring one by almost 50%. We have designed both Nb-wiring and Al-wiring mixers below and above the gap frequency. A Fourier transform spectrometer (FTS) has been constructed especially for the study of the frequency response of SIS receivers. This FTS features large aperture size (10 inch) and high frequency resolution (114 MHz). The FTS spectra, obtained using the SIS receivers as direct detectors on the FTS, agree quite well with our theoretical simulations. We have also, for the first time, measured the FTS heterodyne response of an SIS mixer at sufficiently high resolution to resolve the LO and the sidebands. Heterodyne measurements of our SIS receivers with Nb-wiring or Al-wiring have yielded results which arc among the best reported to date for broadband heterodyne receivers. The Nb-wiring mixers, covering 400 - 850 GHz band with four separate fixed-tuned mixers, have uncorrected DSB receiver noise temperature around 5hv/kb to 700 GHz, and better than 540 K at 808 GHz. An Al-wiring mixer designed for 1050 GHz band has an uncorrected DSB receiver noise temperature 840 K at 1042 GHz and 2.5 K bath temperature. Mixer performance analysis shows that Nb junctions can work well up to twice the gap frequency and the major cause of loss above the gap frequency is the rf losses in the microstrip tuning structures. Further advances in THz SIS mixers may be possible using circuits fabricated with higher-gap superconductors such as NbN. However, this will require high-quality films with low RF surface resistance at THz frequencies.

•Sep 1, 1997•8 citations

A Quantum-limited Submillimeter Mixer with an Inhomogeneous Distributed SIS Junction Array

WL Shan, Sc. Shi, Yutaro Sekímoto +1 more

Heterodyne mixing performance of a waveguide SIS mixer with inhomogeneous distributed junction (DJ) array composed of 3 SIS junctions is experimentally investigated at 375-500 GHz. Quantum-limited noise temperature of 3-DJ mixer is demonstrated. Besides its low noise temperature, the mixer conversion gain of 3-DJ mixer is found to be more uniform over RF band than that of a PCTJ (parallel-connected twin junctions) mixer. The FTS (Fourier transform spectrum) response indicates a broad RF bandwidth of the 3-DJ mixer that is limited by the bandwidth of waveguide probe instead of mixer's tuning circuit.

International Conference on Microwave and Millimeter Wave Technology (ICMMT)•Apr 1, 2007•0 citations

Fundamental and harmonic submillimeter-wave emission from parallel Josephson junction arrays

Faouzi M. Boussaha, Morvan C. Salez, A. Féret +6 more

We report heterodyne measurements of Josephson microwave radiation emitted by a parallel array of small superconductor-insulator-superconductor (SIS) junctions at submillimeter-wave frequencies. The array consists of five Nb/Al–AlOx/Nb junctions nonevenly distributed in a niobium superconducting stripline, and is optimized for rf coupling in the 450–640 GHz range. We observed Fiske-like resonant steps in its I-V curve in the presence of magnetic field. The device was placed in a waveguide mount, and its radiation was quasioptically coupled out of the cryostat, to a SIS-mixer spectrometer in the same frequency range, with a 4–8 GHz band for spectral analysis. We detected a coherent signal in the spectra when the array was biased on the first and third steps, respectively, at the first harmonic frequency of 242 GHz and at the fundamental frequency of 493 GHz, both being the Josephson frequencies associated with their dc voltages. This strongly suggests that this type of parallel arrays optimized for wideband rf coupling, though strongly discretized, hosts dynamic fluxon regimes similar to long Josephson junctions, which could find applications in superconducting digital electronics or integrated heterodyne submillimeter-wave receivers.

Journal of Applied Physics•Apr 1, 2009•7 citations

A quantum-limited submillimeter mixer with an inhomogeneous distributed SIS junction array

Wenlei Shan, Sheng‐Cai Shi, Yutaro Sekímoto +1 more

Heterodyne mixing performance of a waveguide SIS mixer with inhomogeneous distributed junction (DJ) array composed of 3 SIS junctions is experimentally investigated at 375-500 GHz. Quantum-limited noise temperature of 3-DJ mixer is demonstrated. Besides its low noise temperature, the mixer conversion gain of 3-DJ mixer is found to be more uniform over RF band than that of a PCTJ (parallel-connected twin junctions) mixer. The FTS (Fourier transform spectrum) response indicates a broad RF bandwidth of the 3-DJ mixer that is limited by the bandwidth of waveguide probe instead of mixer's tuning circuit.

•Jan 1, 2007•0 citations

0.5-THz waveguide SIS mixers with NbN/AlN/NbN technology

Jing Li, Masanori Takeda, Zhen Wang +1 more

Heterodyne mixers based on superconducting SIS (superconductor-insulator-superconductor) tunnel junctions have been demonstrated to be the most sensitive coherent detectors at millimeter and submillimeter wavelengths. In fact, conventional superconducting SIS mixers with Nb/AlOx/Nb junction and Nb/SiO2/Nb tuning circuit have shown good performances with the noise temperature reaching as low as three times the quantum limit below 0.7THz, which is the gap frequency of Nb-based SIS junctions. However, due to the large loss in Nb thin-film superconducting microstrip lines, the noise performance of Nb SIS mixers deteriorates significantly above 0.7THz. With a gap frequency double that of Nb-based SIS junctions, NbN-based SIS junctions are of particular interest for the development of heterodyne mixers in the terahertz region. Considering the bandwidth and output power of local-oscillator (LO) signal sources are quite limited around 1THz, we firstly develop a waveguide NbN-based SIS mixer at 0.5THz. Three types of SIS junctions, i.e., long junction, parallel-connected tunnel junction (PCTJ) and distributed junction array (DJ) are investigated. They are all comprised of NbN-AlN-NbN tri-layer fabricated on an MgO substrate and have the same current density (Jc) of 10kA/cm2. In this paper, we describe their design, fabrication and preliminary experimental results.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Nov 29, 2007•3 citations
The study of submillimeter-wave radiation in astronomy and atmospheric sciences requires increasingly performant receivers, in particular allowing extended spectral line surveys. To this end, we are developing a quantum-noise limited heterodyne receiver based on SIS junction parallel arrays with broad (larger than 30%) fixed tuned bandwidth. Simulations show that networks of junctions (N>2) of micronic size, embedded in a superconducting inicrostrip line, can provide a bandwidth in excess of the ultimate limit for a single or even twin junction device. These circuits can be viewed as passband filters which have been optimized by varying the spacings between junctions. The results of simulations are confirmed by the first heterodyne measurements in the 480-650GHz bandwidth, and by preliminary FTS measurements beyond. The influence of the Josephson effect in these devices is also investigated.
Observation and analysis of submillimeter-wave radiation (300GHz-3THz) in astronomy and atmospheric sciences requires increasingly performant receivers. The most sensitive receivers working in this range of electromagnetic spectrum use superconductor-insolator-superconductor (SIS) junctions. In order to increase the bandwidth and the sensitivity, we are developing a quantum-noise limited heterodyne receiver based on several parallel SIS junctions with broad (larger than 30%) fixed tuned bandwidth. These circuits can be viewed as passband filters which have been optimized by varying the spacings between junctions. We have designed such 5-junction arrays for operation in the range 480-640 GHz. Fabrication and heterodyne characterization of these devices has been done. The 1 μm2 junctions current density ranges from 4 to 13 kA/cm2, using optical lithography and Nb/Al2Nb5/Nb trilayer sputtering technology. The fabrication process and yield are presented in this paper, along with measured performances
This thesis describes the development of low-noise heterodyne receivers at THz frequencies for submillimeter astronomy using Nb-based superconductor-insulator-superconductor (SIS) tunneling junctions. The mixers utilize a quasi-optical configuration which consists of a planar twin-slot antenna and antisymmetrically-fed two-junctions on an antireflection-coated silicon hyperhemispherical lens. On-chip integrated tuning circuits, in the form of microstrip lines, are used to obtain maximum coupling efficiency in the designed frequency band. To reduce the rf losses in the integrated tuning circuits above the superconducting Nb gap frequency (~ 700 GHz), normal-metal Al is used to replace Nb as the tuning circuits. To account the rf losses in the micros trip lines, we calculated the surface impedance of the AI films using the nonlocal anomalous skin effect for finite thickness films. Nb films were calculated using the Mattis-Bardeen theory in the extreme anomalous limit. Our calculations show that the losses of the Al and Nb microstrip lines are about equal at 830 GHz. For Al-wiring and Nb-wiring mixers both optimized at 1050 GHz, the RF coupling efficiency of Al-wiring mixer is higher than that of Nb-wiring one by almost 50%. We have designed both Nb-wiring and Al-wiring mixers below and above the gap frequency. A Fourier transform spectrometer (FTS) has been constructed especially for the study of the frequency response of SIS receivers. This FTS features large aperture size (10 inch) and high frequency resolution (114 MHz). The FTS spectra, obtained using the SIS receivers as direct detectors on the FTS, agree quite well with our theoretical simulations. We have also, for the first time, measured the FTS heterodyne response of an SIS mixer at sufficiently high resolution to resolve the LO and the sidebands. Heterodyne measurements of our SIS receivers with Nb-wiring or Al-wiring have yielded results which arc among the best reported to date for broadband heterodyne receivers. The Nb-wiring mixers, covering 400 - 850 GHz band with four separate fixed-tuned mixers, have uncorrected DSB receiver noise temperature around 5hv/kb to 700 GHz, and better than 540 K at 808 GHz. An Al-wiring mixer designed for 1050 GHz band has an uncorrected DSB receiver noise temperature 840 K at 1042 GHz and 2.5 K bath temperature. Mixer performance analysis shows that Nb junctions can work well up to twice the gap frequency and the major cause of loss above the gap frequency is the rf losses in the microstrip tuning structures. Further advances in THz SIS mixers may be possible using circuits fabricated with higher-gap superconductors such as NbN. However, this will require high-quality films with low RF surface resistance at THz frequencies.
Heterodyne mixing performance of a waveguide SIS mixer with inhomogeneous distributed junction (DJ) array composed of 3 SIS junctions is experimentally investigated at 375-500 GHz. Quantum-limited noise temperature of 3-DJ mixer is demonstrated. Besides its low noise temperature, the mixer conversion gain of 3-DJ mixer is found to be more uniform over RF band than that of a PCTJ (parallel-connected twin junctions) mixer. The FTS (Fourier transform spectrum) response indicates a broad RF bandwidth of the 3-DJ mixer that is limited by the bandwidth of waveguide probe instead of mixer's tuning circuit.
We report heterodyne measurements of Josephson microwave radiation emitted by a parallel array of small superconductor-insulator-superconductor (SIS) junctions at submillimeter-wave frequencies. The array consists of five Nb/Al–AlOx/Nb junctions nonevenly distributed in a niobium superconducting stripline, and is optimized for rf coupling in the 450–640 GHz range. We observed Fiske-like resonant steps in its I-V curve in the presence of magnetic field. The device was placed in a waveguide mount, and its radiation was quasioptically coupled out of the cryostat, to a SIS-mixer spectrometer in the same frequency range, with a 4–8 GHz band for spectral analysis. We detected a coherent signal in the spectra when the array was biased on the first and third steps, respectively, at the first harmonic frequency of 242 GHz and at the fundamental frequency of 493 GHz, both being the Josephson frequencies associated with their dc voltages. This strongly suggests that this type of parallel arrays optimized for wideband rf coupling, though strongly discretized, hosts dynamic fluxon regimes similar to long Josephson junctions, which could find applications in superconducting digital electronics or integrated heterodyne submillimeter-wave receivers.
Heterodyne mixing performance of a waveguide SIS mixer with inhomogeneous distributed junction (DJ) array composed of 3 SIS junctions is experimentally investigated at 375-500 GHz. Quantum-limited noise temperature of 3-DJ mixer is demonstrated. Besides its low noise temperature, the mixer conversion gain of 3-DJ mixer is found to be more uniform over RF band than that of a PCTJ (parallel-connected twin junctions) mixer. The FTS (Fourier transform spectrum) response indicates a broad RF bandwidth of the 3-DJ mixer that is limited by the bandwidth of waveguide probe instead of mixer's tuning circuit.
Heterodyne mixers based on superconducting SIS (superconductor-insulator-superconductor) tunnel junctions have been demonstrated to be the most sensitive coherent detectors at millimeter and submillimeter wavelengths. In fact, conventional superconducting SIS mixers with Nb/AlOx/Nb junction and Nb/SiO2/Nb tuning circuit have shown good performances with the noise temperature reaching as low as three times the quantum limit below 0.7THz, which is the gap frequency of Nb-based SIS junctions. However, due to the large loss in Nb thin-film superconducting microstrip lines, the noise performance of Nb SIS mixers deteriorates significantly above 0.7THz. With a gap frequency double that of Nb-based SIS junctions, NbN-based SIS junctions are of particular interest for the development of heterodyne mixers in the terahertz region. Considering the bandwidth and output power of local-oscillator (LO) signal sources are quite limited around 1THz, we firstly develop a waveguide NbN-based SIS mixer at 0.5THz. Three types of SIS junctions, i.e., long junction, parallel-connected tunnel junction (PCTJ) and distributed junction array (DJ) are investigated. They are all comprised of NbN-AlN-NbN tri-layer fabricated on an MgO substrate and have the same current density (Jc) of 10kA/cm2. In this paper, we describe their design, fabrication and preliminary experimental results.