Extreme nonlinear phenomena in NbN superconducting stripline resonators

We study giant nonlinear phenomena that emerge near a bifurcation threshold (BT) in a microwave superconducting stripline resonator. Above the BT the system becomes astable and self-sustained modulation of the reflected power off the resonator occurs. The giant nonlinearity manifests itself in an extremely high intermodulation gain, accompanied by a very strong noise squeezing and period doubling of various orders.