Mutual Inductance Coupled through Superconducting Thin Film in Niobium Josephson Integrated Circuits

Abstract

We present numerical and experimental investigation on mutual inductance coupled through a superconducting Nb thin film. The inductance extraction program FastHenry with superconductor support is used for numerical calculation. The self- and mutual inductances of two superconducting strip lines are calculated as functions of the width of the shield layer inserted between them. The results demonstrate that the mutual coupling is reduced with increasing shield layer width. A superconducting quantum interference method is employed to measure the mutual inductance on Nb IC chips. The experimental results of the mutual inductance agree with the calculated results.