Investigation of nonlinear superconducting microwave resonators including Nb Josephson junctions and SQUID arrays

Motivated by the realization of bifurcation regimes of operation, we report on experiments with superconducting microwave resonators comprising short serial arrays of Nb/AlOx/Nb SIS Josephson junctions and low-inductance SQUIDs. These elements provide sufficiently large Josephson inductance LJ ∝ N (N is the number of elements in the chain) enabling nonlinear dynamics of the circuits and detection of low power signals.