Optical Waveguide Device Asymmetric Angles Reflection Loss

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Solution Overview

Problem

Existing optical waveguide devices face issues with high reflection at the end face and require a prism to convert beams into collimated parallel beams, leading to increased size and complexity.

Innovation Solution

The optical waveguide device features inclined output waveguides with respect to the substrate end face and a cylindrical lens to ensure parallel beams, eliminating the need for a prism and reducing reflection by adjusting the angles of the waveguides and lens configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If output waveguides are installed perpendicular to the end face, then the structure is simple, but the reflection at the end face is large and reflected light returns to the output waveguides

Engineering Contradiction:
Improvewaveguide structureVSAvoidreflected light
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The output waveguides are configured at asymmetric angles (first angle and second angle) relative to the normal of the end face, rather than being perpendicular. This asymmetric arrangement causes reflected light to diverge at different angles, preventing it from returning to the waveguides while maintaining structural simplicity.

Inventive Principle:
Principle #4Asymmetry

2Ease of operation

If a prism is used to convert beams into collimated parallel beams, then the beams are properly aligned, but the size of the optical waveguide device increases

Engineering Contradiction:
Improvebeam alignmentVSAvoiddevice size
Core Design Contradiction:
Ease of operationVSVolume of stationary object

Solution Approach 1:

The prism component is completely removed from the optical system. Instead of using a prism to convert beams into collimated parallel beams, the patent employs a lens combined with the asymmetrically angled waveguides to achieve the same beam alignment function, thereby reducing device size while maintaining proper beam alignment.

Inventive Principle:
Principle #2Taking out (Extraction)

3Object-generated harmful factors

If output waveguides are inclined with respect to the end face, then reflected light is reduced, but the waveguide configuration becomes more complex

Engineering Contradiction:
Improvereflected lightVSAvoidwaveguide configuration
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The waveguides are configured at different asymmetric angles (first angle and second angle) relative to the normal of the end face. This asymmetric configuration effectively reduces reflected light by causing it to diverge, while the angles are designed to be symmetrical with respect to the normal line, maintaining a degree of structural regularity that limits complexity.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent optimizes specific parameters including the first angle, second angle, and the distance between waveguides to achieve the desired reflection reduction. By carefully selecting these parameters, the patent balances reflection reduction with structural simplicity.

Inventive Principle:
Principle #35Parameter changes

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 configuration results in a compact optical waveguide device with reduced reflected light and minimized size, achieving a reflection loss of up to 55 dB by optimizing the angles of the output waveguides and using a polarization beam combining unit to align polarized beams.

Implementation Method 1

a lens that allows the beams respectively output from the first and second output waveguides to be parallel to each other

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

since the output waveguides 108 and 109 are installed so as to be perpendicular to the end face, there are problems in that the reflection at the end face is large and the reflected light return to the output waveguides 108 and 109 is large

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

Two beams of which the polarization planes are inclined with respect to each other by 90° are output to the same optical path by the element to combine polarization beam 40

Methodology Applied
Scientific EffectPolarisation: Polarisation

Data Source

PatentEP2485076B1Optical waveguide device
Publication Date: 2020.06.17 SUMITOMO OSAKA CEMENT CO LTD
  • EP2485076B1 patent drawingFigure 1
  • EP2485076B1 patent drawingFigure 2
  • EP2485076B1 patent drawingFigure 3

AI summary

Provided is a small optical waveguide device with little reflected light, the optical waveguide device including: an optical waveguide element of which a first output waveguide is inclined with respect to an output end face and a second output waveguide is inclined with respect to both the first output waveguide and the output end face; and a lens that allows beams respectively output from the first and second output waveguides to be parallel to each other.