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Applied Physics Letters

X-band singly degenerate parametric amplification in a Josephson tunnel junction

J. Mygind, N. F. Pedersen, O. H. Soerensen

Published Jan 1, 1978• 24 citations
Publisher

Abstract

Preliminary measurements on a (quasi-) degenerate parametric amplifier using a single Josephson tunnel junction as the active element is reported. The pump frequency is at 18 GHz and the signal and idler frequencies are both at about 9 GHz. A power gain of 16 dB in a 4-MHz 3-dB bandwidth is achieved at the top of the cryostat.
DOI
10.1063/1.89844

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We have observed doubly degenerate parametric amplification and oscillation at 36 GHz from a single point-contact Josephson junction. The experimental results agree qualitatively with theoretical calculations based on the resistively shunted junction model. The estimated noise temperature of an amplifier with 11 dB net gain is consistent with zero, but has an upper limit of 50 K. Attempts to observe parametric amplification in the singly degenerate mode with a pump frequency of 72 GHz were not successful.
We have observed doubly degenerate parametric amplification and oscillation at 36 GHz from a single point contact Josephson junction. The experimental results agree qualitatively with theoretical calculations based on the resistively shunted junction model. The estimated noise temperature of an amplifier with 11 dB net gain is consistent with zero, but has an upper limit of 50 K. Attempts to observe parametric amplification in the singly degenerate mode with a pump frequency of 72 GHz were not successful. (Author)
Progress on the development of a low-noise superconducting parametric amplifier operated at liquid helium temperatures and designed for practical use with a radio telescope at 33 GHz is reported. Series arrays of small Pb - Pb oxide - Pb tunnel junctions (\sim 20 \mum × 20 μm) are coupled in a microstrip configuration and the Josephson device is operated as a reflection-type amplifier in the doubly degenerate mode. Various practical considerations in using such a devise on a telescope are reviewed. In preliminary experiments, gains of greater than 13 dB have been observed near 33 GHz.