Josephson Distributed Amplifier Delay Matching for Wideband Low-Power Links

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Solution Overview

Problem

Conventional distributed amplifiers are inefficient and inoperable with high-speed superconducting systems due to poor power matching and phasing, making it difficult to establish data links at low bit error rates in high clock rate and low signal power environments.

Innovation Solution

A superconducting distributed amplifier using Josephson transmission lines and lumped resonant circuits with voltage sources, where each stage includes a combination of inductors and capacitors forming a resonant circuit, and set/reset signals are provided by Josephson transmission lines to achieve high clock rates and low signal power amplification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional distributed amplifiers use resistive termination and standard transmission lines, then they achieve wideband amplification, but they suffer from poor efficiency due to inability to achieve power matching and phasing simultaneously

Engineering Contradiction:
Improveamplifier efficiencyVSAvoidpower matching and phasing performance
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent changes the termination from conventional resistive termination to superconducting termination, and transforms the transmission lines into Josephson transmission lines. This parameter change enables simultaneous achievement of power matching and phasing, resolving the efficiency problem while maintaining wideband amplification capability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces conventional electronic components with superconducting components. Specifically, standard transmission lines are replaced with Josephson transmission lines, and resistive terminators are replaced with superconducting terminators. This substitution enables operation at high clock rates (10-40 GHz) with extremely low signal power levels (2-8 nW) that are characteristic of superconducting digital circuits.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Speed

If conventional distributed amplifiers operate at standard electronics speeds, then they achieve adequate signal amplification, but they cannot operate with high-speed superconducting systems requiring 10-40 GHz clock rates and 2-8 nW signal power levels

Engineering Contradiction:
Improveclock rateVSAvoidsignal power level
Core Design Contradiction:
SpeedVSPower

Solution Approach 1:

The patent replaces conventional electronic amplification components with superconducting components including Josephson transmission lines and superconducting active devices. This substitution enables the amplifier to operate at high clock rates (10-40 GHz) while handling extremely low signal power levels (2-8 nW) required by superconducting digital circuits.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operating parameters of the amplifier by using superconducting materials and Josephson junctions, which enable operation at much higher frequencies and lower power levels compared to conventional electronics. The use of Josephson transmission lines with specific characteristic impedances allows matching to superconducting digital circuit interfaces.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If conventional distributed amplifiers use standard transmission lines, then they achieve moderate bandwidth, but they cannot achieve the required bandwidth-gain product for 10 Gb/S NRZ data transmission

Engineering Contradiction:
Improvebandwidth-gain productVSAvoiddata transmission reliability
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The patent changes the transmission line technology from conventional coaxial or stripline to Josephson transmission lines. These superconducting transmission lines provide lower loss and higher bandwidth, enabling the amplifier to achieve the necessary bandwidth-gain product for 10 Gb/S NRZ data transmission while maintaining signal integrity and low bit error rates.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution achieves higher bandwidth-gain product and supports 10 Gb/S NRZ data, improving efficiency and enabling reliable data links in high-speed superconducting systems.

Implementation Method 1

Each amplification stage comprises two Josephson junctions arranged in a superconducting-quantum-interference-device (SQUID)

Methodology Applied
Scientific EffectJosephson effect: Josephson Effect

Implementation Method 2

each stage includes a combination of inductors and capacitors forming a resonant circuit

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP2313972B1Method and apparatus for josephson distributed output amplifier
Publication Date: 2013.09.04 NORTHROP GRUMMAN SYSTEMS CORP
  • EP2313972B1 patent drawingFigure 1
  • EP2313972B1 patent drawingFigure 2
  • EP2313972B1 patent drawingFigure 3

AI summary

The disclosure generally relates to a method and apparatus for providing high-speed, low signal power amplification. In an exemplary embodiment, the disclosure relates to a method for providing a wideband amplification of a signal by forming a first transmission line in parallel with a second transmission line, each of the first transmission line and the second transmission line having a plurality of superconducting transmission elements, each transmission line having a transmission line delay; interposing a plurality of amplification stages between the first transmission line and the second transmission line, each amplification stage having an resonant circuit with a resonant circuit delay; and substantially matching the resonant circuit delay for at least one of the plurality of amplification stages with the transmission line delay of at least one of the superconducting transmission lines.