Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Compact Three Terminal Josephson Switch

IP.com Disclosure Number: IPCOM000053015D
Original Publication Date: 1981-Aug-01
Included in the Prior Art Database: 2005-Feb-12
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Faris, SM: AUTHOR [+2]

Abstract

This article relates to circuits in which the output is isolated from the input and, more particularly, to a three-terminal Josephson junction switch which is nonreciprocal and allows an input signal to be directly injected.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 72% of the total text.

Page 1 of 2

Compact Three Terminal Josephson Switch

This article relates to circuits in which the output is isolated from the input and, more particularly, to a three-terminal Josephson junction switch which is nonreciprocal and allows an input signal to be directly injected.

Fig. 1 shows an isolator circuit 1 consisting of Josephson junctions J1-J3. Gate current Ig is connected to device J1 and, under usual conditions, flows mainly therein to ground. Part of Ig may flow in devices J2,J3 which shunt device J1. An input Iin is applied between devices J2,J3, while an output Iout is taken from between devices J1,J2. Device J3 is used in this circuit as a resistor by operating it in a nonhysteretic mode (see original), where Io3 is its critical current, R is its quasiparticle tunnel resistance, and C(j3) is its capacitance). Junctions J1,J2 operate in an hysteretic mode.

With gate current Ig flowing mainly in J1, an input signal Iin is applied, causing current to flow in device J3 and switching it to the resistive state. Current Iin, is then diverted into devices J2,J1 which then switch to the voltage state, diverting gate current Ig to a load in the form of Iout. Because J2 is hysteretic, its resistance is much larger than that of J3 and, as such, the input current, Iin, flows through the resistance of J3, while gate current Iout remains in the load. Since virtually no current flows in either J1 or J2, the circuit acts as an isolator. Because the resistor is eliminated, the iso...