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US 4,275,314 AGranted
Josephson Atto-Weber switch
AssigneeBell Telephone Laboratories, Incorporated
InventorTheodore A. Fulton
Life of this patent
Estimating the term…
Abstract
A current-switched gate is described which comprises two Josephson tunnel junctions and a small resistor in a triangular loop. Directly combined bias and control currents flow through one junction in the zero-voltage state, causing the switching. The second junction and the resistor provide isolation between input and output after switching. Switching speeds of a few tens of picoseconds and the microwatt power dissipation are attained. Latching as well as nonlatching schemes and memory circuits are described.
Claims17
A Josephson junction circuit comprising
- a Josephson junction gate capable of being switched between a low impedance state at V=0 and a high impedance state at V.noteq.0,
- bias electrode means (14) for applying primary bias current to said gate,
- an output line (12) having an impedance connected to said gate,
- control electrode means (10) for applying control current to said gate for switching said gate from V=0 to V.noteq.0 and to divert said primary bias current to said output line, characterized in that said gate comprises
- at least three circuit branches interconnected at three nodes (N1, N2, N3), said first node being connected to said control electrode means and said second node being connected to said output line and to said bias electrode means,
- a first Josephson junction (J1) in the branch between said second and third nodes,
- a second Josephson junction (J2) in the branch between said first and second nodes, and
- a resistor (r) in the branch between said first and third nodes,
- the critical currents of said junctions and said primary bias current (I.sub.b) being mutually adapted to initially bias said junctions into their V=0 states and to sequentially switch said junctions to V.noteq.0, when said control current (I.sub.c) is applied, thereby causing said primary bias current to flow into said output line and said control current to flow through said resistor and said third node.
6 more elements
A Josephson junction circuit comprising
- a Josephson junction gate capable of being switched between a low impedance state at V=0 and a high impedance state at V.noteq.0,
- bias electrode means (14) for applying primary bias current to said gate,
- an output line (12) connected to said gate, said output line having an impedance,
- control electrode means (10) for applying control current to said gate for switching said gate from V=0 to V.noteq.0 and to divert said primary bias current to said output line, characterized in that said gate comprises
- at least three circuit branches interconnected at three nodes (N1, N2, N3) forming a loop circuit, said first node being connected to said control electrode means and said second node being connected to said output line, and said bias electrode means being adapted to inject said primary bias current into said loop circuit,
- a first Josephson junction (J1) in the branch between said second and third nodes,
- a second Josephson junction (J2) in the branch between said first and second nodes, and
- a resistor (r) in the branch between said first and third nodes,
- the critical currents of said junctions and said primary bias current (I.sub.b) being mutually adapted to initially bias said junctions into their V=0 states and to sequentially switch said junctions to V.noteq.0, when said control current (I.sub.c) is applied, thereby causing said primary bias current to flow into said output line and said control current to flow through said resistor and said third node.
6 more elements
Dependencies are inferred from the claim text.