Elliptical Optical Waveguide for Low-Loss Light Circulation

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Solution Overview

Problem

Existing optical waveguides face challenges in efficiently propagating light with minimal loss, particularly in devices requiring multiple light circulations, such as optical concentration measuring instruments, due to structural limitations and material interactions.

Innovation Solution

The optical waveguide design incorporates an elliptical light circulation portion with floating waveguides connected at specific angles to the circulation portion, supported by a cladding layer and substrate, enhancing light propagation efficiency and reducing losses through multiple circulations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If light circulates multiple times in a conventional waveguide, then optical path length increases, but propagation loss increases

Engineering Contradiction:

Improveoptical path lengthVSAvoidpropagation loss

Core Design Contradiction:

Length of moving objectVSLoss of energy

Solution Approach 1:

The patent employs an elliptical waveguide structure instead of a conventional rectangular or circular waveguide. The elliptical geometry enables light to follow a curved path that naturally guides light circulation while reducing scattering losses at corners and interfaces. This curved optical path allows multiple circulations without significant energy loss, resolving the contradiction between increasing optical path length and maintaining low propagation loss.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent introduces an asymmetric design where the waveguide cross-section and arrangement are non-uniform. This asymmetry creates specific optical modes that are confined more effectively within the waveguide, reducing leakage losses. The asymmetric structure allows light to circulate multiple times while maintaining better confinement and reducing the impact of material absorption and scattering, thus extending optical path length without proportionally increasing propagation loss.

Inventive Principle:

Principle #4Asymmetry

2Ease of manufacture

If waveguide structure is simplified, then manufacturing ease increases, but optical coupling efficiency decreases

Engineering Contradiction:

Improvemanufacturing easeVSAvoidoptical coupling efficiency

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The elliptical waveguide structure serves multiple functions simultaneously: it guides light propagation, provides optical circulation path, and enables efficient coupling between different waveguide sections. The unified elliptical geometry eliminates the need for complex corner reflections or additional coupling components, maintaining manufacturing simplicity while achieving high optical coupling efficiency through the inherent optical properties of the elliptical shape.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Length of moving object

If light circulation portion size is increased, then optical path length per unit area increases, but device area increases

Engineering Contradiction:

Improveoptical path length per unit areaVSAvoiddevice area

Core Design Contradiction:

Length of moving objectVSArea of stationary object

Solution Approach 1:

The elliptical waveguide utilizes its curved geometry to maximize the optical path length within a compact footprint. The curved walls of the elliptical structure enable light to traverse longer paths through refraction and total internal reflection without requiring a proportionally larger device area. This curved optical path efficiently packs the circulation length into a compact spatial envelope, resolving the contradiction between optical path length per unit area and overall device area.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 design increases the optical path length per unit area, improving sensitivity in optical concentration measuring instruments by minimizing propagation losses and enhancing optical coupling efficiency.

Implementation Method 1

light introduced from the light introduction portion propagates through the first waveguide, the light circulation portion, and the second waveguide, in order

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentUS20250298205A1Optical waveguide and optical concentration measuring instrument

Publication Date: 2025.09.25 ASAHI KASEI MICRODEVICES CORP

AI summary

There is provided an optical waveguide including: light introduction portion; a light extraction portion; a light circulation portion of an elliptical shape; a first waveguide which is connected to the light introduction portion at a starting end of the first waveguide in a propagation direction of light, and which is connected to the light circulation portion at a terminal end of the first waveguide; a second waveguide which is connected to the light circulation portion at a starting end of the second waveguide in a propagation direction of light, and which is connected to the light extraction portion at a terminal end of the second waveguide; and a support layer which supports the light circulation portion, in which a center of gravity of the light circulation portion is arranged at a position deviated from an extension direction of the first waveguide and the second waveguide, in a top plan view.