Fujitsu Corporation

Shinya Hasuo

Hideo Suzuki

Norio Fujimaki

A Josephson-junction logic circuit comprises at least one Josephson-junction logic gate which has a variable threshold-type superconductive quantum interference element. The Josephson-junction logic gate comprises a superconductive inductance loop, and at least two Josephson junctions included in the superconductive loop. At least two current-injection lines connected to the superconductive loop and at least one magnetically coupled line are provided. The magnetically coupled line is placed so as to be magnetically coupled to the inductance. Because of this construction, the number of inputs can be increased. Also, various logical functions can be obtained. Further, various logic circuits can be formed by simply changing the photomask for the wiring between the gates.

Josephson-junction logic circuit

This invention discloses a decoder circuit utilizing Josephson devices where Josephson AND gates, output lines connecting both terminals of each said Josephson device and an input signal line are provided in as many as 2.sup.n in number in the nth stage of plural stages. The Josephson AND gate turns ON with the logical product (AND) of the current flowing into the output line of said Josephson AND gate of the preceding stage and the current flowing into the input signal line of the pertinent stage and causes a current to flow into the respective output line.

Decoder circuit utilizing josephson devices

A superconductive logic device incorporating at least one Josephson junction comprises two superconductive electrodes, that is, a base electrode and a counter electrode with a thin insulating layer therebetween. The counter electrode has an extension for receiving an input signal and another extension connected to a ground plane. The input signal current which is supplied from the counter electrode to the ground plane acts on the Josephson junction with a magnetic field, while, a bias current is supplied from the base electrode and flows through the Josephson junction to the ground plane.

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Yokohama, Japan

Shinya Hasuo