Quantum Oscillator Groups With Circulators to Limit Crosstalk

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In quantum devices with oscillators having frequency variability connected to a common transmission line, crosstalk between oscillators is a significant issue that affects the performance and fidelity of signal readout, particularly in Josephson parametric oscillators.

Innovation Solution

The implementation of a quantum device configuration that includes multiple oscillator groups and circulators on a common transmission path, where each circulator is configured to transmit signals from one end to the oscillator groups while blocking signals from the other end, allowing for the setting of oscillation frequencies to minimize crosstalk by ensuring frequency differences between oscillators exceed the susceptibility range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple oscillators are connected to a common transmission line, then signal transmission capability is improved, but crosstalk between oscillators increases

Engineering Contradiction:

Improvesignal transmission capabilityVSAvoidcrosstalk between oscillators

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system divides oscillators into multiple groups (first oscillator group, second oscillator group, etc.), with each group connected to a separate circulator. This segmentation allows independent control and frequency management of each group, reducing mutual interference and crosstalk while maintaining common transmission line connectivity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Circulators are introduced as intermediary devices between the oscillators and the common transmission line. Each circulator manages the signal flow for its connected oscillator group, enabling bidirectional communication while preventing reverse signal propagation that causes crosstalk. The circulator acts as a mediator that maintains signal integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If oscillators with frequency variability are used, then adaptability is improved, but frequency management complexity increases

Engineering Contradiction:

Improvefrequency variability utilizationVSAvoidfrequency management complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system exploits the inherent frequency variability of oscillators by assigning different frequency ranges to different oscillator groups. The first oscillator group operates in a first frequency range while the second oscillator group operates in a second frequency range. This parameter-based differentiation simplifies frequency management by naturally separating the operational bands of different oscillator groups.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system dynamically assigns oscillators to different groups based on their frequency characteristics. Oscillators are not statically fixed but are dynamically categorized into appropriate groups according to their operating frequencies, allowing the system to adaptively manage frequency resources and simplify control complexity.

Inventive Principle:

Principle #15Dynamics

3Object-affected harmful factors

If band-pass filters are added to reduce crosstalk, then signal isolation is improved, but device complexity and loss increase

Engineering Contradiction:

Improvesignal isolationVSAvoiddevice complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The invention extracts the signal isolation function from traditional band-pass filters and transfers it to the circulator-based frequency management system. By separating oscillators into different frequency ranges and using circulators to manage signal flow, the system achieves signal isolation without requiring additional band-pass filters, thereby reducing device complexity and associated losses.

Inventive Principle:

Principle #2Taking out (Extraction)

4Area of stationary object

If oscillators are placed closer together on the transmission line, then space utilization is improved, but crosstalk increases

Engineering Contradiction:

Improvespace utilizationVSAvoidcrosstalk between oscillators

Core Design Contradiction:

Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

Instead of separating oscillators in the spatial dimension (which would reduce space utilization), the system separates them in the frequency dimension. By assigning different frequency ranges to different oscillator groups and using circulators to manage frequency-based signal routing, the system achieves effective isolation while maintaining compact spatial arrangement.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS20250023517A1Quantum device, oscillation frequency setting method, and recording medium

Publication Date: 2025.01.16 NEC CORP

AI summary

A quantum device includes: oscillator groups; circulators; and a transmission path common to the circulators. Each of the oscillator groups includes one or more oscillators having frequency variability. The one or more oscillators are connected to one port of one circulator of the circulators. The one circulator is common to the one or more oscillators. Each of the circulators is arranged on the transmission path. Each of the circulators is configured to: transmit a signal from a first end of the transmission path to the oscillator groups; transmit a signal from any of the oscillator groups to a second end of the transmission path; block a signal from the second end so as not to transmit the signal to the oscillator group; and block a signal from any of the oscillator groups so as not to transmit the signal to the first end.