Fabrication and characteriation of Josephson parametric amplifiers
M.H.J. de Jong (TU Delft - Applied Sciences)
Ines C. Rodrigues – Mentor
D. Bothner – Mentor
G Steele – Mentor
L. Kuipers – Graduation committee member
Akira Endo – Graduation committee member
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Abstract
In this thesis, a we have designed and fabricated a Josephson Parametric Amplifier (JPA) using a new double-angle evaporation method without a Dolan bridge. We have found and resolved several issues in the fabrication procedure, but it requires further tuning before being fully functional. We have also simulated the behaviour of a general parametric amplifier with an additional Duffing non-linear term, and found that this term appears to limit the oscillation amplitude. We have attempted to characterize Josephson junctions fabricated with the new double-angle evaporation procedure, but without much success. Using a different fabrication method, a JPA was made and successfully characterized. The maximum measured gain is 16 dB, with a bandwidth of 1 MHz. The noise temperature is comparable to the cryostat temperature of 250 mK, but it was not characterized accurately.