Optical Josephson Waveform Generation for High-Bandwidth Voltage Pulses

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Solution Overview

Problem

Conventional Josephson arbitrary waveform synthesizers (JAWS) face limitations in generating high-frequency, high-voltage arbitrary waveforms due to bandwidth constraints and electrical transmission line losses, making it difficult to drive a large number of Josephson junctions efficiently.

Innovation Solution

An optical-based method using optical-to-electrical converters and Josephson junctions, where optical pulses are distributed via waveguides to convert into driving current pulses, generating quantized voltage pulses with reduced transmission line lengths, allowing for high integration density and reduced electrical losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional electrical transmission lines are used to drive Josephson junctions, then the system can operate with electrical signals, but bandwidth is limited and transmission losses increase

Engineering Contradiction:

ImprovebandwidthVSAvoidtransmission line losses

Core Design Contradiction:

SpeedVSLoss of energy

Solution Approach 1:

The patent replaces electrical transmission lines with optical waveguides to transmit signals to Josephson junctions. Optical signals have inherently higher bandwidth and lower loss characteristics compared to electrical signals, directly resolving the contradiction between achieving high bandwidth and minimizing transmission losses.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces optical-to-electrical converter units as intermediary components that convert optical pulses into electrical current pulses to drive the Josephson junctions. This intermediary conversion enables the system to leverage the advantages of optical transmission (high bandwidth, low loss) while still utilizing Josephson junctions that respond to electrical signals.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If the number of Josephson junctions is increased to drive more qubits, then system capacity increases, but transmission line bandwidth limitations and losses worsen

Engineering Contradiction:

Improvesystem capacityVSAvoidtransmission line losses

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent segments the system into multiple independent optical channels, each with its own optical-to-electrical converter unit driving a subset of Josephson junctions. This segmentation allows each channel to operate independently with optimized transmission characteristics, enabling the system to scale to drive more qubits without suffering from cumulative transmission losses.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from electrical signal transmission to optical signal transmission, representing a dimensional change in the signal carrier. This transition enables the system to achieve higher bandwidth and lower losses, facilitating the driving of a larger number of Josephson junctions and qubits.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Device complexity

If electrical transmission lines are used, then the system structure is simpler, but electrical losses increase and bandwidth is constrained

Engineering Contradiction:

Improvesystem structureVSAvoidbandwidth

Core Design Contradiction:

Device complexityVSSpeed

Solution Approach 1:

The patent introduces optical-to-electrical converter units as intermediary components that bridge the optical transmission domain and the electrical Josephson junction domain. While this adds some structural complexity, it enables the system to achieve significantly higher bandwidth and lower losses, representing a worthwhile trade-off for advancing quantum computing capabilities.

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

Enables the generation of high-frequency, high-voltage arbitrary waveforms with reduced noise and increased bandwidth, suitable for quantum computing and metrological applications, with voltage levels traceable to international standards.

Implementation Method 1

using the optical-to-electrical converter units (OEU1, OEU2) to convert the optical pulses (OPAT1, OPAT2) into electric driving current pulses (EPAT1)

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 2

generating voltage pulses (V1(t), V2(t)) by driving Josephson junctions (JJ1) with the electric driving current pulses (EPAT1)

Methodology Applied

Scientific EffectJosephson Effect: Josephson Effect

Data Source

PatentUS12368514B2Method and apparatus for providing a voltage

Publication Date: 2025.07.22 TEKNOLOGIAN TUTKIMUSKESKUS VTT OY

AI summary

A method for generating a voltage waveform includesproviding an optical signal, which comprises one or more sequences of optical pulses,distributing the optical pulses via optical waveguides to a plurality of optical-to-electrical converter units,using the optical-to-electrical converter units to convert the optical pulses into electric driving current pulses,generating voltage pulses by driving Josephson junctions with the electric driving current pulses.