Superconducting Transmission Driver With SFQ Pulse Filtering

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Solution Overview

Problem

Existing superconducting inter-chip communication systems face degradation in bandwidth and pulse integrity due to dispersion on long transmission lines, particularly at frequencies over 100 GHz, leading to reliability issues in data transmission.

Innovation Solution

A superconducting transmission driver system incorporating a latching gate stage with Josephson junctions and a low-pass filter stage to convert single flux quantum (SFQ) pulses into pulse signals for transmission, along with a self-reset stage to manage oscillating voltages and reset the latching gate, thereby reducing bandwidth and improving pulse integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If SFQ pulses are transmitted over long superconducting transmission lines at high frequencies (over 100 GHz), then bandwidth is maintained for high-speed communication, but pulse integrity and reliability degrade due to dispersion

Engineering Contradiction:
Improvecommunication speedVSAvoidpulse integrity
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent introduces a low-pass filter as an intermediary component between the SFQ pulse source and the transmission line. This filter mediates the signal by removing high-frequency components that cause dispersion, allowing the signal to travel longer distances without degradation while maintaining acceptable transmission speeds

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the frequency parameters of the signal by using a low-pass filter to remove high-frequency components above a threshold frequency. This parameter transformation converts the high-frequency SFQ pulses into lower-frequency signals that are less susceptible to dispersion effects on long transmission lines

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the bandwidth is reduced to improve pulse integrity, then dispersion effects are minimized, but communication speed decreases

Engineering Contradiction:
Improvepulse integrityVSAvoidcommunication speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent segments the frequency spectrum by using a low-pass filter to separate useful signal components from harmful high-frequency components. This segmentation allows the system to transmit at optimized speeds while filtering out frequencies that would cause dispersion, achieving a balance between speed and reliability

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If inter-chip communication uses multiple transition stages (chip vias, bump bonds, board vias), then chip-to-chip communication is enabled, but bandwidth degradation increases

Engineering Contradiction:
Improveinter-chip communication capabilityVSAvoidbandwidth
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent places low-pass filters at strategic intermediary points in the inter-chip communication path, particularly at the output of the SFQ pulse generator and at receiver inputs. These intermediary filters protect the signal from bandwidth degradation through multiple transition stages by removing high-frequency components before they encounter dispersion in bump bonds and board vias

Inventive Principle:
Principle #24Intermediary (Mediator)

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 system significantly reduces bandwidth degradation, enhancing pulse integrity and reliability of data transmission across inter-chip communication systems, allowing for longer transmission line lengths with improved manufacturing efficiency and reduced dispersion effects.

Implementation Method 1

a latching gate stage comprising at least one Josephson junction configured to switch from an off state to an oscillating voltage state to provide an oscillating voltage at a control node in response to a single flux quantum (SFQ) pulse

Methodology Applied
Scientific EffectJosephson effect: Josephson Effect

Implementation Method 2

a low-pass filter stage coupled to the control node and configured to convert the oscillating voltage to a pulse signal to be transmitted over a transmission line

Methodology Applied
Scientific EffectLow-pass filtering: Filter (electronic)

Data Source

PatentEP3542463B1Superconducting transmission driver system
Publication Date: 2021.01.27 NORTHROP GRUMMAN SYSTEMS CORP
  • EP3542463B1 patent drawingFigure 1
  • EP3542463B1 patent drawingFigure 2
  • EP3542463B1 patent drawingFigure 3

AI summary

One example includes a superconducting transmission driver system (12). The system includes a latching gate stage (18) comprising at least one Josephson junction configured to switch from an off state to an oscillating voltage state to provide an oscillating voltage (Vosc) at a control node in response to a single flux quantum, SFQ, pulse received at an input (RQLIN). The system further includes a low-pass filter stage (20) coupled to the control node and configured to convert the oscillating voltage (Vosc) to a pulse signal (PLS) to be transmitted over a transmission line(16).