Cascaded Josephson Amplifiers for Nonoverlapping Microwave Bands

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Solution Overview

Problem

Current microwave directional amplifiers in quantum computing are limited in amplifying signals across nonoverlapping bandwidths, as they either amplify or pass signals based on frequency alignment with their operational bandwidth, leading to inefficiencies in handling frequency-multiplexed microwave signals.

Innovation Solution

A cascading multi-path interferometric Josephson directional amplifier system using nondegenerate three-wave-mixing Josephson parametric devices, where each amplifier in the cascade has a distinct operating bandwidth, allowing for selective amplification or pass-through of signals based on frequency alignment with their respective bandwidths, thereby expanding the overall amplification bandwidth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single microwave directional amplifier is used, then it can amplify signals within its operational bandwidth, but it cannot amplify signals across nonoverlapping bandwidths

Engineering Contradiction:

Improveamplification bandwidth coverageVSAvoidamplifier system structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides the amplification task into multiple segments by using several directional amplifiers, each responsible for a specific nonoverlapping bandwidth. Each amplifier processes a distinct frequency range, and the combined system achieves broad bandwidth coverage without requiring a single complex wideband amplifier.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If multiple amplifiers with nonoverlapping bandwidths are cascaded, then the overall amplification bandwidth is expanded, but signal routing and frequency selection become more complex

Engineering Contradiction:

Improvetotal amplification bandwidthVSAvoidfrequency multiplexing management

Core Design Contradiction:

Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent employs dynamic frequency-selective routing where the signal path through the cascaded amplifiers is determined by the input signal's frequency. Each amplifier dynamically processes only the frequency components within its designated bandwidth, enabling automatic frequency-based signal routing without complex external control mechanisms.

Inventive Principle:

Principle #15Dynamics

3Productivity

If frequency-multiplexed microwave signals are processed, then signal processing efficiency is improved, but noise introduction increases

Engineering Contradiction:

Improvesignal processing efficiencyVSAvoidnoise in amplified signals

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

Each directional amplifier in the cascade is optimized for its specific frequency band, providing high-quality amplification with minimal noise for signals within its operational bandwidth. This localized optimization ensures that each amplifier contributes minimally to noise while maximizing signal processing efficiency for its designated frequency range.

Inventive Principle:

Principle #3Local quality

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 effectively amplifies or passes signals across a broader bandwidth than individual amplifiers, enhancing the capability to handle frequency-multiplexed microwave signals without introducing significant noise, thus improving signal processing efficiency in quantum computing applications.

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 parametric devices

Methodology Applied

Scientific EffectJosephson effect: Josephson Effect

Implementation Method 3

cascading multi-path interferometric Josephson directional amplifiers

Methodology Applied

Scientific EffectInterference: Interference

Data Source

PatentEP3718208B1Amplification of frequency multiplexed microwave signals using cascading multi-path interferometric josephson directional amplifiers with nonoverlapping bandwidths

Publication Date: 2021.12.15 INTERNATIONAL BUSINESS MACHINE CORPORATION

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AI summary

A cascading microwave directional amplifier (cascade) (302) includes a set of Josephson devices (302(1)-302(n)), each Josephson device in the set having a corresponding operating bandwidth (BW(1)-BW(n)) of microwave frequencies (f1-fn), wherein different operating bandwidths have different corresponding center frequencies. A series coupling is formed between first Josephson device (302(1)) from the set and an nthJosephson device (302(n)) from the set, such that the first Josephson device (302(1)) amplifies a signal of a first frequency (f1, BW(1)) from a frequency multiplexed microwave signal (multiplexed signal) (f1-fn) and propagate without amplification a signal of an nthfrequency (f2-fn), and the nthJosephson device (302(n)) to amplify the signal of the nthfrequency (fn, BW(n)) and propagate without amplification the signal of the first frequency (f1-f(n-1)) from the multiplexed signal in the first signal flow direction through the series.