Holographic Diffraction Structure for Optical Coupling

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Solution Overview

Problem

Current optical coupling methods between photonic circuits from different technologies, such as silicon nitride and III-V materials, face challenges in alignment precision and incur significant optical losses due to mode size differences and misalignment, especially when integrating disparate photonic circuits or connecting them to optical fibers.

Innovation Solution

An optical coupling device employing a holographic diffraction structure that guides and adapts light beams between photonic circuits, allowing for alignment flexibility and reduced losses by compensating for mode differences without the need for intermediate elements, and can couple light beams from non-parallel and spaced-apart optical guiding devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional optical coupling methods are used between photonic circuits from different technologies, then alignment precision is improved, but optical losses increase due to mode size differences and misalignment

Engineering Contradiction:
Improvealignment precisionVSAvoidoptical losses
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The patent introduces a holographic diffraction structure as an intermediary element between the first and second photonic circuits. This holographic element acts as a mediator that receives light from the first circuit and redirects it to the second circuit, compensating for mode size differences and misalignment. The holographic structure is configured with specific diffraction angles and positions to match the optical modes between disparate photonic circuits, thereby reducing optical losses while maintaining alignment flexibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If intermediate elements are used to match mode sizes, then optical coupling efficiency is improved, but device complexity increases

Engineering Contradiction:
Improveoptical coupling efficiencyVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into a single holographic diffraction structure. This single element simultaneously performs mode size matching, angular redirection, and spatial positioning that would traditionally require separate components such as telescopic lenses, prisms, and alignment mechanisms. By combining these functions into one integrated holographic element, the device complexity is reduced while maintaining high optical coupling efficiency between photonic circuits with different mode characteristics.

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If active alignment procedures are performed to achieve precise alignment, then coupling precision is improved, but assembly time and cost increase

Engineering Contradiction:
Improvecoupling precisionVSAvoidassembly time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The holographic diffraction structure is designed and manufactured with pre-configured geometric parameters that encode the desired optical coupling characteristics. The hologram is recorded with specific object and reference beams positioned at predetermined angles and locations, so that when the structure is illuminated, it automatically redirects light to the correct destination without requiring active alignment adjustments. This preliminary configuration of the holographic parameters eliminates the need for time-consuming active alignment procedures while maintaining high coupling precision.

Inventive Principle:
Principle #10Preliminary 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 holographic diffraction structure enables efficient optical coupling with improved alignment precision, reduced costs, and lower complexity, effectively minimizing optical losses even when dealing with photonic circuits of varying sizes and orientations.

Implementation Method 1

at least one holographic diffraction structure configured to guide and adapt the first light beam between the first and second optical inputs-outputs of the optical coupling device

Methodology Applied
Scientific EffectHolographic diffraction: Diffraction

Data Source

PatentEP4390483A1Optical coupling device with holographic diffraction structure
Publication Date: 2024.06.26 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP4390483A1 patent drawingFigure 1~3
  • EP4390483A1 patent drawingFigure 4~5
  • EP4390483A1 patent drawingFigure 6~7

AI summary

Optical coupling device (100) configured to optically couple a first optical guiding device (102) to a second optical guiding device (104), comprising at least a first optical input-output through which the first optical guiding device is intended to emit and/or receive a first light beam (103), and a second optical input-output through which the second optical guiding device is intended to receive and/or emit the first light beam, further comprising at least one holographic diffraction structure (108) configured to guide and adapt the first light beam between the first and second optical input-outputs of the optical coupling device.