Parametric amplification with weak-link nonlinearity in superconducting microresonators

Abstract

Nonlinear kinetic inductance in a high Q superconducting coplanar waveguide\nmicroresonator can cause a bifurcation of the resonance curve. Near the\ncritical pumping power and frequency for bifurcation, large parametric gain is\nobserved for signals in the frequency band near resonance. We show experimental\nresults on signal and intermodulation gain which are well described by a theory\nof the parametric amplification based on a Kerr nonlinearity. Phase dependent\ngain, or signal squeezing, is verified with a homodyne detection scheme.\n