Multilevel Back-Propagation Device for Compact Photonic Architectures

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Solution Overview

Problem

Current integrated photonic architectures for projectors, such as retinal projectors, face challenges in reducing bulk to increase component density and integrate more components due to significant surface area occupation by addressing and projection parts.

Innovation Solution

A multilevel feedback device is introduced, allowing for the superimposition of waveguides on different levels with a coupling portion and reflector to change the direction of light radiation, effectively 'folding' the architecture and reducing bulk, enabling compactness and efficient light propagation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If conventional photonic architecture with separate addressing and projection parts is used, then functional requirements are met, but chip area is significantly large

Engineering Contradiction:
Improvechip areaVSAvoidfunctional integration
Core Design Contradiction:
Area of stationary objectVSAdaptability or versatility

Solution Approach 1:

The patent transitions from a planar layout to a three-dimensional stacked architecture by introducing vertical coupling between addressing waveguides and projection waveguides through evanescent coupling regions. This allows the addressing part and projection part to occupy different vertical levels (z-dimension) while maintaining horizontal integration, thereby significantly reducing the chip area footprint while preserving full functional capability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Quantity of substance

If waveguides are brought closer together to increase component density, then component density increases, but parasitic coupling increases

Engineering Contradiction:
Improvecomponent densityVSAvoidparasitic coupling
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent implements nested waveguide structures where addressing waveguides and projection waveguides are vertically stacked within the same horizontal footprint. The evanescent coupling regions are precisely positioned between adjacent waveguide levels, allowing strong coupling for signal transfer while maintaining spatial separation that prevents unwanted parasitic coupling between waveguides on the same level.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Volume of moving object

If multi-level superimposition is implemented, then compactness is achieved, but coupling precision requirements increase

Engineering Contradiction:
Improvedevice bulkVSAvoidcoupling precision
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The patent introduces evanescent coupling regions as intermediary structures that mediate the interaction between addressing waveguides and projection waveguides. These coupling regions act as transition zones that gradually transfer optical energy between waveguide levels, providing a controlled and predictable coupling mechanism that is less sensitive to manufacturing variations compared to direct waveguide contacts, thereby reducing precision requirements while maintaining compact multi-level integration.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution significantly reduces the bulk of photonic architectures, allowing for increased component density and efficient light extraction with reduced optical losses, while maintaining energy efficiency and compactness.

Implementation Method 1

a coupling portion in which the first and second waveguides are coupled by proximity such that the electromagnetic radiation propagates from the first level to the second level

Methodology Applied
Scientific EffectEvanescent coupling:

Implementation Method 2

at least one reflector at one end of the coupling portion, configured to reflect the electromagnetic radiation

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP4390480A1Multilevel back propagation device
Publication Date: 2024.06.26 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP4390480A1 patent drawingFigure 1~2
  • EP4390480A1 patent drawingFigure 3A~3B
  • EP4390480A1 patent drawingFigure 4A~4C

AI summary

The invention relates to a multilevel backcoupling device for electromagnetic radiation, comprising at least a first level (n1) and a second level (n2) at least partially superimposed, the first level comprising a first waveguide (11) intended to guide the propagation of the light radiation in a first direction (s1) and the second level comprising a second waveguide (21) intended to guide the propagation of the light radiation in a second direction (s2) opposite to the first direction, the device comprising: • a coupling portion (3) in which the first and second waveguides are coupled by approaching each other so that the electromagnetic radiation propagates from the first level (n1) to the second level (n2), and • at least one reflector (4) at one end (30) of the coupling portion (3), configured to reflect the electromagnetic radiation.