EPJ Quantum Technol. (2016) 3: 10
https://doi.org/10.1140/epjqt/s40507-016-0048-2

Research

Tunable coupling of transmission-line microwave resonators mediated by an rf SQUID

¹ Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching, 85748, Germany
² Physik-Department, Technische Universität München, Garching, 85748, Germany
³ Nanosystems Initiative Munich (NIM), Schellingstraße 4, München, 80799, Germany
⁴ Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Cambridge, Massachusetts, 02138, United States
⁵ Instituto de Física Fundamental IFF-CSIC, Calle Serrano 113b, Madrid, 28006, Spain
⁶ Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, Bilbao, 48080, Spain
⁷ IKERBASQUE, Basque Foundation for Science, Maria Diaz  de Haro 3, Bilbao, 48013, Spain

^* e-mail: Rudolf.Gross@wmi.badw.de

Received: 14 March 2016
Accepted: 8 July 2016
Published online: 28 July 2016

Abstract

We realize tunable coupling between two superconducting transmission line resonators. The coupling is mediated by a non-hysteretic rf SQUID acting as a flux-tunable mutual inductance between the resonators. We present a spectroscopic characterization of the device. In particular, we observe couplings ranging between −320 MHz and 37 MHz. In the case of , the microwave power cross transmission between the two resonators is reduced by almost four orders of magnitude as compared to the case where the coupling is switched on.