Ion Trap Electrode Switching With Low-Pass Filtering for Noise Control

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Solution Overview

Problem

Ion traps in quantum computing and atomic clocks face challenges in controlling ions due to sensitivity to electric field noise, which causes heating and limits coherence times, especially with rapid handling and precise control requirements.

Innovation Solution

A system using digital-to-analog converters (DACs) with filtered switches to control ion movement, employing a filter leg and bypass leg configuration that slows voltage transients and minimizes discontinuities in the electric field, reducing noise and heating effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If rapid voltage switching is used to quickly reposition ions, then ion handling speed is improved, but electric field noise and ion heating increase

Engineering Contradiction:
Improveion handling speedVSAvoidelectric field noise
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by pre-charging capacitors to the target voltage level before switching. The capacitors are charged in advance through current-limited paths, so when the switch closes, the voltage transition is already minimized because the capacitor is pre-conditioned to the desired state, reducing the abruptness of the voltage change and associated noise

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses capacitors as intermediary energy storage elements between the voltage source and the ion trap electrode. These capacitors act as buffers that smooth out voltage transitions by charging/discharging through controlled current paths, thereby mediating the interaction between the switching circuit and the sensitive ion trap to reduce noise

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If current-limited switching is used to reduce voltage transients, then ion heating is reduced, but switching speed decreases

Engineering Contradiction:
Improveion heatingVSAvoidswitching speed
Core Design Contradiction:
Object-affected harmful factorsVSSpeed

Solution Approach 1:

The current-limited path is prepared in advance with the capacitor charged to the target voltage. This preliminary charging action allows the system to achieve both current limitation (reducing heating) and relatively fast switching, because the energy is already stored and ready to be transferred without requiring a slow charge-up process at the moment of switching

Inventive Principle:
Principle #10Preliminary action

3Duration of action of stationary object

If voltage transients are slowed to reduce noise, then ion coherence time is extended, but ion repositioning precision may be affected

Engineering Contradiction:
Improvecoherence timeVSAvoidion positioning precision
Core Design Contradiction:
Duration of action of stationary objectVSManufacturing precision

Solution Approach 1:

The patent changes the parameter of voltage transition characteristics by controlling the current limit and capacitor charging time constant. By adjusting these parameters, the system optimizes the balance between transition smoothness (extending coherence time) and transition accuracy (maintaining positioning precision), allowing the voltage to reach the correct value through a controlled, noise-minimized path

Inventive Principle:
Principle #35Parameter changes

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 filtered switching system effectively reduces ion heating and enhances control precision, allowing for smoother voltage transitions and improved ion handling in ion traps, thereby extending coherence times and maintaining precise ion control.

Implementation Method 1

the filter portion and the capacitor form a filter between the DAC and the electrode

Methodology Applied
Scientific EffectRC filtering: Filter (electronic)

Implementation Method 2

the electrode element configured to provide, according to a supplied DAC voltage, an electrical field for controlling movement of an ion

Methodology Applied
Scientific EffectElectrical field generation: Electric Field

Implementation Method 3

the filter leg switch is configured to selectively couple the first DAC through the first filter leg to the electrode

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4351001A1Ion movement control system with low pass filter in analog switch
Publication Date: 2024.04.10 INFINEON TECH AUSTRIA AG
  • EP4351001A1 patent drawingFigure 1
  • EP4351001A1 patent drawingFigure 2
  • EP4351001A1 patent drawingFigure 3A

AI summary

An ion trap system with low pass filter switch, including a digital to analog converter (DAC) connected to a first port and enabled to provide a DAC voltage, an electrode element connected to a second port, the electrode element configured to provide an electrical field for controlling a position of an ion, and a filter switch between the first port and the second port and having a filter leg and a bypass leg in parallel, the filter leg having a filter leg switch and a filter portion between the first port and the second port and selectively coupling the first port through the filter leg to the second port to slow a voltage transient of the DAC voltage to the electrode element, and where the bypass leg has a bypass leg switch that selectively couples the first port directly to the second port.