Nonlinear Resonant Element Embedded in Laser Cavity for Photon Pair Generation

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Solution Overview

Problem

Current methods for exciting narrow resonances in nonlinear media for photon pair generation are inefficient and unstable, particularly when using continuous wave lasers, leading to non-separable photon states and power loss due to spectral mismatch, and require complex active locking schemes.

Innovation Solution

Embedding a nonlinear resonant element directly into an external laser cavity and using mode-locking techniques to achieve stable pulsed excitation, allowing for bandwidth-matched pulses that match the resonance, thereby enhancing power coupling and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a continuous wave laser is used to excite a narrow resonance in a nonlinear medium, then power coupling efficiency is improved, but the generated photon pairs are not single-frequency mode and thus not pure

Engineering Contradiction:

Improvepower coupling efficiencyVSAvoidphoton pair purity

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The patent applies periodic pulsed excitation instead of continuous wave excitation. The pulsed laser provides time-gated excitation that allows the resonance to be excited efficiently while the pulse duration and timing control ensure that only photons generated during the pulse window are collected, thereby achieving both high power coupling efficiency and high photon pair purity through temporal gating

Inventive Principle:

Principle #19Periodic action

2Manufacturing precision

If a pulsed laser is used to excite a narrow resonance, then photon pair purity is improved, but power coupling efficiency deteriorates due to spectral bandwidth mismatch

Engineering Contradiction:

Improvephoton pair purityVSAvoidpower coupling efficiency

Core Design Contradiction:

Manufacturing precisionVSLoss of energy

Solution Approach 1:

The patent uses periodic pulsed excitation where the pulse repetition rate and duration are optimized to match the resonance characteristics. This allows the pulsed laser to achieve both high photon pair purity through temporal gating and high power coupling efficiency by synchronizing the pulse timing with the resonance response, eliminating the spectral bandwidth mismatch problem

Inventive Principle:

Principle #19Periodic action

3Loss of energy

If a continuous wave laser is used for excitation, then power coupling efficiency is improved, but synchronization with electronic systems becomes impossible

Engineering Contradiction:

Improvepower coupling efficiencyVSAvoidsynchronization capability

Core Design Contradiction:

Loss of energyVSEase of operation

Solution Approach 1:

The patent employs periodic pulsed excitation with a well-defined repetition rate that can be synchronized with electronic systems. The pulsed nature provides clear temporal markers for triggering electronic detectors and modulators, while the periodic structure maintains efficient power coupling through resonant enhancement at each pulse, thereby achieving both synchronization capability and power efficiency

Inventive Principle:

Principle #19Periodic action

4Stability of the object's composition

If external laser locking schemes are implemented to stabilize resonance excitation, then stability is improved, but device complexity increases

Engineering Contradiction:

Improveresonance excitation stabilityVSAvoidactive locking scheme complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent merges the laser cavity with the nonlinear resonant element to form an integrated system. This combination eliminates the need for external locking schemes because the laser modes are inherently locked to the resonance through the integrated structure, achieving stable resonance excitation while dramatically reducing device complexity by removing separate locking control systems

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 efficient and stable generation of high-purity, frequency-multiplexed photon pairs with reduced complexity and power consumption, allowing synchronization with electronic systems and compatibility with quantum devices.

Implementation Method 1

the generation of quantum correlated and entangled photon pairs through spontaneous four wave-mixing resonant nonlinear elements such as nonlinear microring resonators

Methodology Applied

Scientific EffectSpontaneous four wave-mixing:

Implementation Method 2

embedding a nonlinear resonant element directly into an external laser cavity and locking the cavity modes

Methodology Applied

Scientific EffectMode-locking:

Implementation Method 3

The use of nonlinear micro cavities with narrow resonances and high Q-factors, i.e. below threshold pumped high-Q optical parametric oscillators

Methodology Applied

Scientific EffectResonance: Resonance

Data Source

PatentUS10505335B2Method and a system for pulsed excitation of a nonlinear medium for photon pair generation

Publication Date: 2019.12.10 INSTITUT NATIONAL DE LA RECHERCHE SCIENTIFIQUE

AI summary

A method and a system for pulsed excitation of a nonlinear medium for photon pair generation, he method comprising exciting a single narrow resonance of a nonlinear resonant element with a pulsed laser field, comprising embedding a nonlinear resonant element directly into an external laser cavity and locking the cavity modes.