A tunable coupler for superconducting microwave resonators using a nonlinear kinetic inductance transmission line.

ABSTRACT: We present a tunable coupler scheme that allows us to tune the coupling strength between a feedline and a superconducting resonator in situ over a wide range. In this scheme, we shunt the feedline with a 50-Ω lumped-element nonlinear transmission line made from a 20 nm NbTiN film. By injecting a DC current, the nonlinear kinetic inductance changes and the effective impedance shunting the resonator periodically varies from a short to an open, which tunes the coupling strength and coupling quality factor Q_c . We have demonstrated Q_c tuning over a factor of 40, between Q_c ~ 5.5 × 10⁴ and Q_c ~ 2.3 × 10⁶, for a 4.5 GHz resonator by applying a DC current less than 3.3 mA. Our tunable coupler sche

SUBMITTER: Bockstiegel C 

PROVIDER: S-EPMC5761681 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature