Bichromatic Laser System for Quantum Gate Precision

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Solution Overview

Problem

Existing technologies face challenges in precisely and accurately delivering laser beams in terms of position, frequency, and phase to atomic systems, particularly in trapped ion quantum computing, where precise control is crucial for quantum gate operations.

Innovation Solution

A bichromatic laser system with a master oscillator, arm splitter, modulator, filter, and acousto-optical modulators is used to generate and stabilize primary and sideband mode beams with controlled frequency and phase differences, coupled with a servo system for real-time phase and frequency adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional laser systems are used to deliver laser beams to atomic systems, then the system structure is simple, but the precision and accuracy of frequency and phase delivery are insufficient for quantum gate operations

Engineering Contradiction:
Improvefrequency and phase delivery precisionVSAvoidlaser system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The laser system is divided into separate arms (first arm and second arm) that independently generate and control primary mode and sideband mode beams. Each arm can be independently optimized for its specific function, allowing precise frequency and phase control while maintaining modular complexity management.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A servo system continuously monitors the frequency and phase of laser beams and provides real-time feedback control. The servo system adjusts modulation parameters to maintain precise frequency separation and phase relationships between beams, compensating for drift and ensuring quantum gate operation accuracy.

Inventive Principle:
Principle #23Feedback

2Reliability

If multiple laser beams with precise frequency and phase control are generated, then quantum gate operations achieve high fidelity, but the system requires complex modulation and control mechanisms

Engineering Contradiction:
Improvequantum gate operation fidelityVSAvoidmodulation and control mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system pre-establishes precise frequency separation between primary mode and sideband mode beams through controlled modulation before the beams interact with atomic objects. Phase relationships are predetermined and stabilized in advance, ensuring that when beams are delivered for quantum gate operations, the required coherence and interference conditions are already optimized.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Acousto-optical modulators serve as intermediary devices that precisely control the frequency and phase characteristics of laser beams. These modulators translate electrical control signals into precise optical frequency and phase adjustments, acting as mediators between the control system and the laser beams to achieve high-fidelity quantum operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If the laser system uses independent arms for primary mode and sideband mode generation, then frequency and phase control is improved, but the system structure becomes more complex

Engineering Contradiction:
Improverelative frequency and phase control precisionVSAvoidarm splitter and optical path complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system combines the primary mode beam and sideband mode beam from separate arms into a unified optical path using a beam combiner. This merging allows the beams to propagate together and interact with atomic objects in a coordinated manner, maintaining the precision benefits of independent arm control while reducing overall system complexity through integrated beam delivery.

Inventive Principle:
Principle #5Merging (Combining)

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 high-fidelity quantum gate operations by ensuring stable relative frequency and phase differences between laser beams, improving the precision and accuracy of quantum computations in trapped atomic object quantum computers.

Implementation Method 1

a master oscillator configured to generate a master beam

Methodology Applied
Scientific EffectStimulated emission: Laser

Implementation Method 2

a modulator configured to modulate the second beam to generate a beam comprising sidebands

Methodology Applied
Scientific EffectFrequency modulation: Phase Modulation

Implementation Method 3

an acousto-optical modulator configured to shift the frequency of each mode of an amplified selected sideband beam to generate a sideband mode beam

Methodology Applied
Scientific EffectAcousto-optic effect: Acousto-optic Effect

Implementation Method 4

an amplifier cavity configured to amplify the particular sideband mode and suppress other residual modes of the selected sideband mode

Methodology Applied
Scientific EffectStimulated emission amplification: Laser

Data Source

PatentEP3832813A1Bichromatic laser for quantum computing applications
Publication Date: 2021.06.09 QUANTINUUM LLC
  • EP3832813A1 patent drawingFigure 1
  • EP3832813A1 patent drawingFigure 2
  • EP3832813A1 patent drawingFigure 3A

AI summary

A multi-frequency laser system comprises a master oscillator to generate a master beam and an arm splitter to split the master beam into a first beam and a second beam. The first beam is provided to a primary mode arm for generation of a primary mode beam and the second beam is provided to a sideband mode arm for generation of a sideband mode beam. The sideband beam arm comprises a modulator to modulate the second beam to generate a beam comprising sidebands; a filter to select a particular sideband mode from the beam comprising sidebands; an amplifier cavity to amplify the particular sideband mode and suppress other residual modes; and an acousto-optical modulator to shift the frequency of each mode of an amplified selected sideband beam to generate a sideband mode beam. The primary and sideband mode beams are provided in a coordinated manner to enact a quantum gate.