Cascaded Josephson Directional Amplifiers for Frequency-Multiplexed Signals

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Solution Overview

Problem

Current multi-path Josephson interferometric directional amplifiers are limited in amplifying frequency-multiplexed microwave signals, as they primarily operate within a narrow bandwidth and fail to effectively amplify signals outside this range, leading to inefficient signal processing in quantum computing applications.

Innovation Solution

The implementation of cascading multi-path interferometric Josephson directional amplifiers with nonoverlapping bandwidths, utilizing nondegenerate three-wave-mixing Josephson devices, allows for selective amplification of specific frequency components within a frequency-multiplexed signal by configuring each amplifier to operate within its unique bandwidth, thereby expanding the overall amplification bandwidth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single multi-path Josephson interferometric directional amplifier is used, then the device complexity is low, but the amplification bandwidth is narrow and cannot handle frequency-multiplexed signals across multiple bands

Engineering Contradiction:
Improveamplification bandwidthVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The amplifier system is segmented into multiple independent multi-path Josephson interferometric directional amplifiers, each tuned to a specific frequency band. Each amplifier handles a distinct portion of the frequency-multiplexed signal, allowing the system to achieve broad bandwidth coverage while maintaining the simplicity of individual amplifier units. The segmented architecture enables parallel processing of different frequency components without requiring complex cross-band interference management.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If multiple amplifiers with overlapping bandwidths are cascaded, then the overall amplification bandwidth increases, but signals experience unintended amplification in multiple bands and increased device complexity

Engineering Contradiction:
Improveamplification bandwidthVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Each amplifier in the cascade is designed with local quality optimization, being tuned to amplify signals within its specific nonoverlapping frequency band while maintaining high selectivity. This localized tuning ensures that each amplifier contributes to only one frequency band, preventing unintended amplification in other bands. The local quality approach allows the cascade to achieve broad overall bandwidth without the complexity of managing overlapping frequency responses.

Inventive Principle:
Principle #3Local quality

3Productivity

If frequency-multiplexed signals are processed through a single amplifier, then the device complexity is low, but signal processing efficiency decreases due to inability to selectively amplify specific frequency components

Engineering Contradiction:
Improvesignal processing efficiencyVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The signal processing function is segmented across multiple amplifiers, each responsible for a specific frequency component of the multiplexed signal. This segmentation enables parallel processing of different frequency channels, significantly improving overall signal processing efficiency. Each amplifier operates independently on its designated frequency band, eliminating the need for complex frequency switching or sequential processing that would be required with a single amplifier.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cascade of amplifiers collectively provides universal frequency coverage, with each amplifier contributing its specialized frequency band to the overall system capability. The multi-functionality is achieved through the combination of specialized units, where each amplifier is optimized for its specific band but together they handle the complete frequency-multiplexed signal spectrum, improving processing efficiency across all channels.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

This approach enables broader bandwidth amplification and selective amplification of specific frequencies, enhancing the efficiency of microwave signal processing in quantum computing by ensuring that only signals within the operational range of each amplifier are amplified, while out-of-band signals are passed without significant gain, thus improving the reliability and precision of quantum computations.

Implementation Method 1

nondegenerate three-wave-mixing Josephson parametric devices

Methodology Applied
Scientific EffectThree-wave-mixing:

Implementation Method 2

Josephson directional amplifiers based on nondegenerate three-wave-mixing Josephson devices

Methodology Applied
Scientific EffectJosephson effect: Josephson Effect

Implementation Method 3

frequency multiplexed microwave signals

Methodology Applied
Scientific EffectFrequency multiplexing:

Implementation Method 4

multi-path interferometric Josephson directional amplifiers

Methodology Applied
Scientific EffectInterference: Interference

Data Source

PatentEP3718207B1Selective amplification of frequency multiplexed microwave signals using cascading multi-path interferometric josephson directional amplifiers with nonoverlapping bandwidths
Publication Date: 2021.08.25 INTERNATIONAL BUSINESS MACHINE CORPORATION
  • EP3718207B1 patent drawingFigure 1
  • EP3718207B1 patent drawingFigure 2
  • EP3718207B1 patent drawingFigure 3

AI summary

A cascading selective microwave directional amplifier (cascade) includes a set of Josephson devices, each Josephson device in the set having a corresponding operating bandwidth of microwave frequencies. Different operating bandwidths have different corresponding center frequencies. A series coupling is formed between first Josephson device from the set and an nth Josephson device from the set. The series coupling causes the first Josephson device to amplify a signal of a first frequency from a frequency multiplexed microwave signal (multiplexed signal) in a first signal flow direction through the series coupling and the nth Josephson device to amplify a signal of an nth frequency in a second signal flow direction through the series, where the second signal flow direction is opposite of the first signal flow direction.