Possible parametric capacitance in Josephson junctions

A. Tagliacozzo, F. Ventriglia

Efrat Shimshoni, Yuval Gefen, Shimon Levit

Zlatko Minev, Ioan M. Pop, Nicholas A. Masluk +2 more

Mark W. Coffey

В. Ч. Жуковский, Позднякова Олеся Дмитриевна, В. Д. Кревчик +2 more

The influence of the internal capacity of a Josephson junction on the parametric amplification of external electromagnetic radiation was studied in terms of a resistively and capacitively shunted junction model. The influence of the McCumber parameter on parametric amplification was clarified. It is shown that the additional regions of amplification can occur near subharmonic Shapiro steps in the case of Josephson junctions with internal capacity.

Mogens T. Levinsen, B. T. Ulrich

A Josephson junction 1.6 mm wavelength microwave source has been used to demonstrate the parametric amplification by reflection necessary to maintain parametric oscillations at 1.6 mm wavelength. A perturbation calculation based on the resistively and capacitively shunted Josephson junction model gives a negative effective microwave resistance for a junction biased at voltages higher than the voltage for a cavity induced step. The parametric oscillation was observed at voltages consistent with the region in which negative resistance was calculated.