Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 19: Superconductivity: Poster Session
TT 19.43: Poster
Montag, 7. März 2016, 15:00–18:00, Poster D
Investigation of a Josephson junction based parametric amplifier — •Patrick Winkel1, Martin Weides1,2, and Alexey V. Ustinov1 — 1Physikalisches Institut, Karlsruher Institut für Technologie, 76131 Karlsruhe — 2Materials Science in Mainz, Johannes Gutenberg-Universität Mainz, 55128 Mainz
We design, fabricate and experimentally investigate a parametric amplifier based on the nonlinear inductance of Josephson junctions. Our design is rather conventional and based on a strongly coupled coplanar waveguide quarter-wave resonator terminated by a SQUID. The SQUID inductance depends periodically on the enclosed magnetic flux inside the loop. This tunable nonlinear inductance is used to adjust the resonance frequency of the whole device. We replace the single SQUID with a series array of SQUIDs to decrease the effective nonlinearity and to increase the dynamic range without affecting the bandwidth. The required pump tone is introduced through a separate flux line by applying an rf-drive. For a critical pump power and detuning between pump and resonance frequency, the system reaches a bifurcation regime. Close to this critical point, the response of the system is highly sensitive to small perturbations, which are intentionally introduced by the signal fed into the amplifier.