Optical Waveguide Electrode Material Zoning

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Solution Overview

Problem

Existing optical waveguide devices struggle to effectively remove unnecessary light propagating in the substrate while minimizing light absorption loss caused by the working electrode.

Innovation Solution

The optical waveguide device incorporates a working electrode with a first base layer made of a material with a low light absorption coefficient, such as niobium, and a conductor pattern with a second base layer made of a material with a higher light absorption coefficient, such as titanium, formed in regions where unnecessary light propagates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If a metal base layer with high light absorption coefficient is used for the working electrode, then unnecessary light propagating in the substrate can be absorbed and removed, but light absorption loss increases for the optical waveguide

Engineering Contradiction:

Improveunnecessary light removalVSAvoidlight absorption loss

Core Design Contradiction:

Object-generated harmful factorsVSLoss of energy

Solution Approach 1:

The base layer is designed with spatially varying light absorption coefficients: the first base layer has low light absorption in the optical waveguide region to minimize loss, while the second base layer has high light absorption in the conductor pattern region to remove unnecessary light. This local differentiation resolves the contradiction by assigning different material properties to different functional zones.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The base layer is segmented into two distinct parts: a first base layer underlying the optical waveguide and a second base layer forming the conductor pattern. This segmentation allows each part to be optimized independently for its specific function, with the first base layer minimizing optical loss and the second base layer maximizing unnecessary light absorption.

Inventive Principle:

Principle #1Segmentation

2Power

If the working electrode is positioned close to the optical waveguide to strengthen electric field interaction, then modulation efficiency improves, but light absorption loss by the metal base layer increases

Engineering Contradiction:

Improvemodulation efficiencyVSAvoidlight absorption loss

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The first base layer is specifically designed with low light absorption coefficient in the region where the working electrode interacts with the optical waveguide. This allows the electrode to be positioned close to the waveguide for high modulation efficiency while the base layer material selection ensures minimal light absorption loss in this critical interaction zone.

Inventive Principle:

Principle #3Local quality

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 enables effective removal of unnecessary light while suppressing light absorption loss, allowing for a modulation operation driven at a lower voltage with appropriate optical characteristics.

Implementation Method 1

a first base layer made of a first material, and a first conductive layer on the first base layer... the first material may have a light absorption coefficient at a wavelength of light propagating through the optical waveguide, which is smaller than a light absorption coefficient of the second material

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

a conductor pattern including a second base layer made of a second material different from the first material... the second material may have a light absorption coefficient at a wavelength of light propagating through the optical waveguide, which is larger than a light absorption coefficient of the first material at the wavelength of the light

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 3

an optical modulation element using LiNbO3 (hereinafter, also referred to as LN) having an electro-optic effect for a substrate can achieve high-frequency optical modulation characteristics

Methodology Applied

Scientific EffectElectro-optic effect: Electro-Optic Effects

Data Source

PatentUS12332534B2Optical waveguide device, optical modulator, optical modulation module, and optical transmission apparatus

Publication Date: 2025.06.17 SUMITOMO OSAKA CEMENT CO LTD

AI summary

There is provided an optical waveguide device including a substrate, an optical waveguide formed on the substrate, and a working electrode that controls a light wave propagating through the optical waveguide, in which the working electrode includes a first base layer made of a first material, and a first conductive layer on the first base layer, and a conductor pattern including a second base layer made of a second material different from the first material and a second conductive layer on the second base layer is formed in a region other than a path from an input end to an output end of the optical waveguide, in a region on the substrate.