Abstract: There is disclosed a structure for coupling between a low temperature circuitry cooled by a cooling system and a room temperature circuitry wherein the structure contains a device for electric connection and a second cooling system specifically for cooling of the electric connection.

Abstract: A superconducting interface circuit converting a signal sent from a normal conducting circuit into a small voltage swing signal suitable for a superconducting circuit includes a superconducting field effect device. The superconducting field effect device has a superconducting channel of an extremely thin oxide superconductor thin film, a superconducting source region and a superconducting drain region of an oxide superconductor thin film positioned at both ends of the superconducting channel, and a gate electrode on the superconducting channel through a gate insulator. The gate electrode of the super-FET is connected to a signal line which transmits a voltage signal from the normal conducting circuit.