Nonlinear Microwave Circuit Based on Niobium Nanobridges Fabricated With Ne FIB
Parth Bhandari, Laith Meti, Tom Godfrey +7 more
Recently the exploration of nonlinear microwave response in superconducting circuits has been extended to Nb nanobridges that can operate at higher magnetic fields, frequencies, and temperatures than their conventional Al counterparts. Nb nanobridge-based Superconducting Quantum Interference Devices (SQUIDs) have shown potential applications in quantum information processing, weak signal detection, and single spin detection. Combining such non-linear elements with circuit Quantum Electrodynamic (QED) elements like coplanar waveguide (CPW) resonators allows the study of the nonlinearity of such systems. In this work we report on the design, fabrication and dispersive microwave readout of a Nb DC nanoSQUID embedded in a superconducting quarter-wavelength resonator. The measured flux-tuneability of the resonance shows a modulation of a few MHz and fits simulations, giving a critical current of 330 μA and a screening parameterβLof 4.07. Following this we present results showing Kerr-type detuning with a pump tone applied to the device.
IEEE Transactions on Applied Superconductivity•Apr 9, 2026•0 citations