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Theory of the singly quasidegenerate Josephson junction parametric amplifier

Journal Article · · J. Appl. Phys.; (United States)
DOI:https://doi.org/10.1063/1.327507· OSTI ID:5129322

A comprehensive account of the theory of the singly quasidegenerate Josephson junction parametric amplifier is given. In this mode the signal and idler frequencies are both approximately equal to half the pump frequency, and hence the signal and idler channels have a common termination. It is shown that the performance of the amplifier characterized by properties such as gain-bandwidth product, noise temperature, and saturation depends strongly on the embedding microwave circuit. In particular any uncompensated series reactance may deteriorate the overall performance. Internal shot and Johnson noise as well as incident thermal radiation is included in the discussion. It is shown that the noise temperature is virtually independent of noise injected from external sources and that minimum noise temperature is automatically achieved if the amplifier is tuned to maximize the gain-bandwidth product. The analytical results are illustrated by self-consistent numerical solutions of the circuit equations.

Research Organization:
Physics Laboratory I, The Technical University of Denmark, DK-2800 Lyngby, Denmark
OSTI ID:
5129322
Journal Information:
J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 51:10; ISSN JAPIA
Country of Publication:
United States
Language:
English