Optoelectronic Device Frequency Comb Generation Mode Filtering

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Solution Overview

Problem

Existing optoelectronic devices for generating frequency combs face challenges in achieving efficient and coherent frequency comb generation due to optical disturbances that degrade the formation of dissipative temporal Kerr solitons, particularly in multimode resonant rings which can interfere with abnormal dispersion regimes.

Innovation Solution

An optoelectronic device comprising a laser source and a ring optical micro-resonator with a filtering guide optically coupled to the resonant ring, where the filtering guide has an effective index matching a higher order optical mode, allowing for the filtering of higher order modes and maintaining abnormal dispersion, thus reducing optical losses and disturbances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the resonant ring is sized to obtain an anomalous dispersion regime, then coherent frequency comb generation is enabled, but the resonant ring becomes multimode causing mode interference and degrading the abnormal dispersion regime

Engineering Contradiction:
Improvecoherent frequency comb generationVSAvoidmode interference
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes the harmful higher-order modes from the resonant ring by introducing a filtering waveguide that selectively couples to and extracts these modes, thereby eliminating mode interference while preserving the fundamental mode and abnormal dispersion regime necessary for coherent frequency comb generation

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The filtering waveguide acts as an intermediary element between the resonant ring and the external environment, mediating the interaction by providing a controlled coupling path that selectively interacts with higher-order modes through evanescent field coupling while leaving the fundamental mode undisturbed

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-generated harmful factors

If a filtering structure is added to suppress higher order modes, then mode interference is reduced, but optical losses increase

Engineering Contradiction:
Improvemode interferenceVSAvoidoptical losses
Core Design Contradiction:
Object-generated harmful factorsVSLoss of energy

Solution Approach 1:

The filtering waveguide is positioned at a specific location on the resonant ring where it provides local mode filtering functionality. The filtering action is localized to specific regions where higher-order modes are extracted, while other regions maintain their original characteristics, thus achieving mode suppression with minimal impact on overall optical circulation

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The filtering waveguide provides partial filtering action by selectively coupling to only the harmful higher-order modes while leaving the fundamental mode unaffected. This partial action approach ensures that filtering is applied only where necessary, minimizing additional optical losses while effectively suppressing mode interference

Inventive Principle:
Principle #16Partial or excessive action

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 device generates a coherent frequency comb with reduced optical losses and increased robustness in maintaining abnormal dispersion, leading to improved coherence and reduced noise, enabling efficient generation of frequency combs with lower pump signal power requirements.

Implementation Method 1

a phenomenon known as four-wave cascading mixing appears which generates, from the fundamental mode supported by the resonant ring 20, a frequency comb

Methodology Applied
Scientific EffectFour-wave mixing:

Implementation Method 2

the resonant ring made of a material with third-order nonlinear optical properties, here silicon nitride

Methodology Applied
Scientific EffectThird-order nonlinear optical effect:

Implementation Method 3

The optical micro-resonator 3 forms an optical parametric oscillator

Methodology Applied
Scientific EffectOptical parametric oscillation:

Implementation Method 4

it is not necessary for the power of the pump signal to be large for the parametric gain to be greater than the optical losses present in the resonant ring

Methodology Applied
Scientific EffectParametric amplification:

Implementation Method 5

The filter guide is optically coupled to the resonant ring in order to extract a higher order mode

Methodology Applied
Scientific EffectEvanescent wave coupling:

Data Source

PatentEP3346328B1Optoelectronic device for generating a coherent frequency comb
Publication Date: 2019.08.28 THALES SA
  • EP3346328B1 patent drawingFigure 1A~1C
  • EP3346328B1 patent drawingFigure 2A~2B
  • EP3346328B1 patent drawingFigure 3A~4B

AI summary

The invention relates to an optoelectronic device for generating a frequency comb comprising: - a laser source (2); - an optical micro-resonator (3), comprising a resonant ring (20); - at least one waveguide (30) optically coupled to the resonant ring (20), having an effective index associated with a fundamental optical mode supported by the filter guide (30) equal to an effective index associated with a higher order optical mode supported by the resonant ring (20).