Squeezed Light Generator Using Nested Optical Cavity

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Solution Overview

Problem

Existing squeezed light generators are bulky, unstable, and have limited squeezing capabilities, making them unsuitable for real-life and laboratory applications, and there is a need for improved noise reduction in light states for applications like extreme sensing and quantum communication.

Innovation Solution

A compact squeezed light generator is designed using a waveguide with a second harmonic generator and a parametric down converter inside an optical cavity resonant for both fundamental and second harmonic light, allowing for efficient generation of squeezed light with high squeezing levels without requiring high-power input, and maintaining long-term stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional squeezed light generation systems are used, then squeezing capability is achieved, but the system becomes bulky and unstable

Engineering Contradiction:
Improvesystem stabilityVSAvoidsystem bulkiness
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent embeds the second harmonic generator inside the optical cavity, creating a nested structure where one optical component is placed within another. This nesting approach consolidates multiple functions into a single integrated system, reducing the overall footprint and improving stability while maintaining squeezing capability.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent combines the second harmonic generator and parametric down converter into a single integrated optical cavity system. By merging these components and making them resonate at the same frequency, the system achieves compactness and improved stability without sacrificing the quantum optical functions needed for squeezed light generation.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If higher squeezing levels are achieved, then noise reduction improves, but system complexity and size increase

Engineering Contradiction:
Improvenoise reduction levelVSAvoidsystem size
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

By nesting the second harmonic generator within the optical cavity, the system achieves efficient frequency conversion in a compact volume. This allows high squeezing levels to be obtained without proportionally increasing system size, as the nested structure maximizes the use of available space.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent utilizes resonant frequency matching between the optical cavity and both the second harmonic generator and parametric down converter. By carefully controlling the resonant parameters and phase matching conditions, the system achieves enhanced squeezing efficiency in a compact configuration without requiring proportional increases in system size.

Inventive Principle:
Principle #35Parameter changes

3Volume of moving object

If compact design is implemented, then system size reduces, but conversion efficiency may decrease

Engineering Contradiction:
Improvesystem sizeVSAvoidconversion efficiency
Core Design Contradiction:
Volume of moving objectVSProductivity

Solution Approach 1:

The nested configuration allows the second harmonic generator to be positioned within the optical cavity, maximizing the interaction length and conversion efficiency within a compact volume. The nesting ensures that the conversion process occurs in close proximity to the resonant cavity, enhancing efficiency without requiring additional space.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

By optimizing the resonant frequency and phase matching parameters of the optical cavity, the system achieves high conversion efficiency in a compact design. The resonant enhancement effect allows efficient energy transfer and conversion without requiring large physical dimensions, thereby maintaining productivity while reducing volume.

Inventive Principle:
Principle #35Parameter changes

4Volume of moving object

If single-pass second harmonic generation is used, then compactness is achieved, but conversion efficiency is limited

Engineering Contradiction:
Improvesystem compactnessVSAvoidsecond harmonic conversion efficiency
Core Design Contradiction:
Volume of moving objectVSProductivity

Solution Approach 1:

The second harmonic generator is nested within the optical cavity, allowing the conversion process to occur in a single pass through the nonlinear material while benefiting from the resonant enhancement of the cavity. This nested arrangement maintains compactness while the cavity resonance compensates for the single-pass limitation, preserving conversion efficiency.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The system utilizes resonant frequency matching and phase matching parameter optimization to enhance the single-pass conversion efficiency. By carefully controlling the optical parameters and resonant conditions, the system achieves efficient second harmonic generation without requiring multiple passes or increasing system complexity.

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 solution achieves a noise level more than 10dB below shot noise, enabling superior squeezing capabilities in a compact and stable setup, suitable for various applications, including quantum communication and sensing.

Implementation Method 1

a waveguide being arranged to receive fundamental wavelength laser light, the waveguide comprising a second harmonic generator for generating second harmonic light from the fundamental wavelength light

Methodology Applied
Scientific EffectSecond harmonic generation: Second Harmonic Generation

Implementation Method 2

a parametric down converter arranged inside said optical cavity, the parametric down converter being adapted for generating said squeezed light using said second harmonic light

Methodology Applied
Scientific EffectParametric down conversion:

Implementation Method 3

an optical cavity resonant for both fundamental wavelength light and the second harmonic light, the optical cavity being arranged to receive the second harmonic light

Methodology Applied
Scientific EffectOptical resonance: Resonance

Data Source

PatentEP3729192B1Squeezed light generator and method for generating squeezed light
Publication Date: 2023.06.07 DANMARKS TEKNISKE UNIV
  • EP3729192B1 patent drawingFigure 1~2B
  • EP3729192B1 patent drawingFigure 3A~4C
  • EP3729192B1 patent drawingFigure 5~7

AI summary

A squeezed light generator (SLG) for generating squeezed light (SQL) is disclosed, said squeezed light generator (SLG) comprising: -a waveguide (WG) being arranged to receive fundamental wavelength laser light (FWL), the waveguide(WG) comprising a second harmonic generator (SHG) for generating second harmonic light (SHL) from the fundamental wavelength light (FWL), -an optical cavity (OC) resonant for both fundamental wavelength light (FWL) and the second harmonic light (SHL), the optical cavity (OC) being arranged to receive the second harmonic light (SHL), and -a parametric down converter (PDC) arranged inside said optical cavity (OC), the parametric down converter (PDC) being adapted for generating said squeezed light (SQL) using said second harmonic light (SHL). Also, a method for generating squeezed light (SQL) is disclosed.