Microstructured Optical Coupling for Multimode Laser Diode Arrays

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Solution Overview

Problem

Current technologies face challenges in efficiently injecting high-power multi-mode laser radiation from semiconductor diode arrays into optical fibers, as the radiation's beam quality and divergence hinder effective coupling, leading to suboptimal power transfer.

Innovation Solution

A light source system featuring a semiconductor chip with a modal transformation device having a microstructured surface that intercepts and transforms the radiation through multiple reflections and transmissions, spatially modifying the phase to align with predefined modes, allowing for efficient coupling into a multimode fiber, achieving over 90% power injection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If conventional optical parts (cylindrical lenses, microlenses) are used to collimate and shape the radiation from laser diodes, then beam quality and symmetry are improved, but device complexity and alignment precision requirements increase

Engineering Contradiction:
Improvebeam qualityVSAvoidoptical system complexity
Core Design Contradiction:
ShapeVSDevice complexity

Solution Approach 1:

The patent combines multiple optical functions (collimation, beam shaping, mode transformation) into a single integrated photonic device structure. The waveguide array simultaneously performs spatial mode transformation and beam conditioning, eliminating the need for separate cylindrical lenses, microlens arrays, and alignment mechanisms, thus reducing overall device complexity while maintaining beam quality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces an intermediary waveguide array structure that acts as a mediator between the laser diode array and the optical fiber. This waveguide array transforms the complex multi-mode radiation from the diodes into predefined spatial modes that efficiently couple to the fiber, simplifying the interface between these two components while maintaining high coupling efficiency

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If multiple optical parts are arranged to transform radiation from side-by-side arrangement to stacked arrangement, then coupling efficiency into optical fiber improves, but alignment precision and manufacturing complexity increase

Engineering Contradiction:
Improvecoupling efficiencyVSAvoidalignment precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent segments the radiation transformation process into discrete waveguide channels, each handling a specific spatial mode transformation. This segmentation allows independent optimization of each waveguide path while maintaining overall system performance, reducing the interdependence and alignment sensitivity between components

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The waveguide array performs preliminary spatial mode transformation of the radiation before it reaches the optical fiber coupling interface. By pre-shaping the beams into the correct spatial modes within the waveguide structure, the system reduces the precision requirements at the final coupling stage, as the beams are already conditioned for efficient fiber coupling

Inventive Principle:
Principle #10Preliminary action

3Shape

If conventional optical assemblies (Southampton assembly, stepped mirrors, Fresnel elements) are used to shape the beam, then beam symmetry and quality improve, but device complexity and number of components increase

Engineering Contradiction:
Improvebeam symmetryVSAvoidnumber of optical components
Core Design Contradiction:
ShapeVSDevice complexity

Solution Approach 1:

The patent merges beam shaping and mode transformation functions into the waveguide array structure itself. The waveguides inherently provide the beam shaping through their geometric configuration and refractive index profile, eliminating the need for separate Southampton assemblies, stepped mirrors, or Fresnel elements, thus achieving beam symmetry with fewer components

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces mechanical optical components (mirrors, lenses, prisms) with a photonic waveguide system. The beam shaping and mode transformation are achieved through optical confinement and wave propagation in the waveguide structure rather than through mechanical reflection and refraction at discrete component interfaces, reducing the number of mechanical parts and assembly steps

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 system effectively transforms the radiation's modes to optimize coupling into the fiber, enhancing beam quality and power transfer efficiency, thereby maximizing the injected optical power.

Implementation Method 1

the modal transformation device being configured to intercept the incident radiation during a plurality of reflections and/or transmissions on the optical part

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

the modal transformation device comprising at least one optical part (5) having a microstructured main surface arranged opposite the semiconductor chip

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

the microstructured main surface configured to spatially modify the phase of the incident radiation

Methodology Applied
Scientific EffectPhase modulation: Phase Modulation

Data Source

PatentEP3987337B1Light source comprising at least one semiconductor chip bearing at least one diode
Publication Date: 2024.07.31 CAILABS
  • EP3987337B1 patent drawingFigure 1~2
  • EP3987337B1 patent drawingFigure 3a~3b
  • EP3987337B1 patent drawingFigure 4

AI summary

The invention relates to a light source (3) comprising: - at least one semiconductor chip (1) capable of emitting incident radiation (I); - an output stage (4) comprising at least one fiber or free space for propagating a plurality of predefined modes; - at least one optical component (5) having a microstructured main surface arranged facing the semiconductor chip (1) so as to intercept the incident radiation (I), spatially modify the phase of the incident radiation (I) and form, via a plurality of reflections and/or transmissions by the optical component, transformed light radiation comprising at least the predefined modes.