Ridge-Type LN Waveguide Modulator with Coplanar RF and Microstrip DC Electrodes

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Solution Overview

Problem

Conventional optical modulators require high drive voltages due to insufficient light confinement and suffer from increased light propagation loss and insertion loss, especially with titanium-diffused waveguides, which limits their efficiency and size.

Innovation Solution

An optical device with an RF electrode in coplanar configuration and a DC electrode in microstrip configuration is used, employing a ridge-type LN thin film waveguide for improved light confinement and reduced drive voltage, while maintaining low insertion loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If titanium-diffused waveguides are used to improve light confinement, then light propagation loss increases and insertion loss increases

Engineering Contradiction:

Improvelight confinementVSAvoidlight propagation loss

Core Design Contradiction:

Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The patent changes the waveguide structure from titanium-diffused to ridge-type, and modifies the electrode configurations (RF electrode to coplanar, DC electrode to microstrip) to alter electrical field distribution parameters, thereby reducing light propagation loss while maintaining light confinement

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure combining ridge-type waveguide with specific electrode materials and configurations, integrating multiple functional elements (waveguide ridges, coplanar RF electrodes, microstrip DC electrodes) to achieve both light confinement and low loss

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If conventional optical modulators are used, then light confinement is insufficient, but drive voltage must be increased to compensate

Engineering Contradiction:

Improvelight confinementVSAvoiddrive voltage

Core Design Contradiction:

Stability of the object's compositionVSPower

Solution Approach 1:

The patent introduces ridge-type waveguide structure that changes the geometric parameters of light confinement, and adopts coplanar/microstrip electrode configurations that change electrical field distribution parameters, achieving improved light confinement without increasing drive voltage

Inventive Principle:

Principle #35Parameter changes

3Volume of moving object

If chip size is reduced, then integration is improved, but light propagation loss may increase

Engineering Contradiction:

Improvechip sizeVSAvoidlight propagation loss

Core Design Contradiction:

Volume of moving objectVSLoss of energy

Solution Approach 1:

The patent optimizes the parameters of ridge-type waveguide and electrode configurations to achieve efficient light confinement within a compact area, allowing chip size reduction without compromising light propagation efficiency

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

The solution enables operation at low RF drive voltage with reduced insertion loss and smaller chip size, enhancing electric-field application efficiency and minimizing light propagation loss.

Implementation Method 1

an optical waveguide formed of a crystal thin film having an electro-optic effect

Methodology Applied

Scientific EffectElectro-optic effect: Electro-Optic Effects

Data Source

PatentUS12019349B2Optical device and optical transceiver using the same

Publication Date: 2024.06.25 FUJITSU OPTICAL COMPONENTS LTD

AI summary

An optical device includes an optical waveguide formed of a crystal thin film having an electro-optic effect, an RF electrode configured to apply a high-frequency voltage to the optical waveguide, and a DC electrode configured to apply a DC voltage to the optical waveguide, wherein the RF electrode has a coplanar electrode configuration, and the DC electrode has a microstrip electrode configuration.