Photonic Chip Etching Layout for Lens-Free Multispectral Imaging

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Solution Overview

Problem

Existing photonic chips are limited to attenuated total internal reflection and face integration and manufacturing challenges due to overlapping waveguide arrangements, and require specific wavelength configurations and dual-sample setups for analysis.

Innovation Solution

A photonic chip design that illuminates scenes with light beams of different wavelengths, utilizing waveguides distributed in the same plane with isotropic or anisotropic etching patterns, allowing for efficient fabrication and integration, and enables reflection and analysis of light beams without additional optical devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If waveguides are stacked in parallel planes for multispectral imaging, then wavelength-specific transmission is improved, but manufacturing complexity and integration difficulty increase

Engineering Contradiction:
Improvewavelength-specific transmissionVSAvoidintegration difficulty
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transitions from a planar waveguide arrangement to a three-dimensional configuration where waveguides are stacked in parallel planes at different heights above the substrate. This vertical dimensionality allows multiple wavelength-specific waveguides to be integrated without overlapping in the horizontal plane, thereby maintaining wavelength discrimination while reducing manufacturing complexity and integration difficulty.

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

2Measurement precision

If waveguides are arranged in overlapping configurations, then spectral resolution is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvespectral resolutionVSAvoidalignment precision
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent resolves the alignment precision challenge by stacking waveguides in vertical layers rather than arranging them in overlapping horizontal configurations. Each waveguide layer is positioned at a different height above the substrate, eliminating horizontal overlap and the associated alignment precision requirements while maintaining spectral resolution through wavelength-specific propagation in each layer.

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

3Measurement precision

If the system is designed for attenuated total internal reflection only, then measurement specificity is improved, but application versatility decreases

Engineering Contradiction:
Improvemeasurement specificityVSAvoidmeasurement method flexibility
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent designs the photonic chip with a substrate that can support multiple measurement methods. The substrate serves as both the reflection surface for attenuated total internal reflection and as a platform for positioning samples in various configurations (reflection, transmission, transflection). The stacked waveguide architecture enables flexible light routing to accommodate different measurement geometries, making the system versatile for multiple analytical techniques.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Measurement precision

If multiple samples are required for interferometric analysis, then measurement accuracy is improved, but device complexity increases

Engineering Contradiction:
Improveinterferometric accuracyVSAvoidsample configuration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent creates a unified measurement platform where a single sample can be analyzed using multiple measurement methods (attenuated total internal reflection, reflection, transmission, transflection) by configuring the light paths through the stacked waveguides. The substrate serves multiple functions as both the optical interface and sample positioning platform, eliminating the need for separate sample configurations for different measurement techniques.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Facilitates homogeneous illumination and compact, efficient multispectral imaging without the need for lenses, supporting a wide range of wavelengths and reducing manufacturing complexities.

Implementation Method 1

Each waveguide includes an associated diffraction grating that extracts light from the waveguide to illuminate a scene positioned on the top surface of the substrate

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

The light extracted from the waveguide is directed onto the substrate surface at the sample. The light is totally reflected at the interface between the substrate surface and the sample

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP4372435B1Photonic chip and infrared imaging system using such a photonic chip
Publication Date: 2025.12.31 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP4372435B1 patent drawingFigure 1A~1B
  • EP4372435B1 patent drawingFigure 2A~2B
  • EP4372435B1 patent drawingFigure 3~4

AI summary

A photonic chip for lighting a scene, the photonic chip comprises: - a substrate (10) including a face with an etching (100), - waveguides extending parallel to a plane formed by the etched face of the substrate (10), configured to guide a light beam, - diffraction gratings (12), respectively formed in one of the waveguides (11) and configured to extract, out of the waveguide (11) in which it is formed and towards the etching (100) of the substrate (10), the light beam, at least two waveguides being configured to receive light beams of different wavelengths, and in which the etching (100) of the substrate (10) is configured to extract the light beams out of the substrate (10), towards the scene to be illuminated, said scene being against the etched face of the substrate (10) and at the level of the etching (100) of the substrate (10).