Wavelength Converter Overcladding for Dust and Optical Loss Control

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Solution Overview

Problem

Ridge-type optical waveguides suffer from issues such as dust attachment, light absorption, damage, decreased thermal conductivity, and TE-TM polarization conversion, leading to increased optical loss and reduced wavelength conversion efficiency.

Innovation Solution

A wavelength converter with an optical waveguide core covered by an overcladding layer having a lower refractive index than the core, combined with a temperature control element to manage environmental influences and reduce TE-TM conversion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a ridge-type optical waveguide is used, then light confinement is improved, but the optical waveguide core surface is exposed causing dust attachment and increased optical loss

Engineering Contradiction:

Improvelight confinementVSAvoiddust attachment

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

A protective film is formed to cover the optical waveguide core surface, preventing dust attachment while maintaining optical performance. The film acts as a barrier between the environment and the waveguide core, solving the dust contamination issue without compromising light confinement.

Inventive Principle:

Principle #30Flexible shells and thin films

2Ease of manufacture

If the optical waveguide core surface is exposed, then manufacturing is simpler, but thermal conductivity decreases and temperature control becomes difficult

Engineering Contradiction:

Improvewaveguide fabricationVSAvoidtemperature control

Core Design Contradiction:

Ease of manufactureVSTemperature

Solution Approach 1:

The protective film covers the waveguide core surface and provides a thermally conductive path to the substrate, improving heat dissipation and temperature control while maintaining manufacturing simplicity.

Inventive Principle:

Principle #30Flexible shells and thin films

3Productivity

If control light with high light intensity propagates through the waveguide core, then wavelength conversion efficiency is improved, but heat generation increases causing optical loss and potential damage

Engineering Contradiction:

Improvewavelength conversion efficiencyVSAvoidoptical loss

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The protective film acts as a thermal management layer that dissipates heat generated by high-intensity control light, preventing excessive heat accumulation and associated optical losses while maintaining high wavelength conversion efficiency.

Inventive Principle:

Principle #30Flexible shells and thin films

4Device complexity

If the optical waveguide core is exposed, then device complexity is reduced, but the core is easily damaged during mounting and operation

Engineering Contradiction:

Improvestructure simplicityVSAvoidcore durability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The protective film provides a hard protective layer over the fragile optical waveguide core, preventing mechanical damage during mounting and operation while adding minimal structural complexity.

Inventive Principle:

Principle #30Flexible shells and thin films

5Ease of manufacture

If air is present above the waveguide core, then manufacturing is easier, but TE-TM polarization conversion occurs and optical loss increases

Engineering Contradiction:

Improvefabrication simplicityVSAvoidoptical loss

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The protective film creates a controlled environment over the waveguide core that prevents TE-TM polarization conversion and reduces optical loss while maintaining manufacturing ease.

Inventive Principle:

Principle #30Flexible shells and thin films

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

Prevents surface contamination, improves temperature control, and expands the usable optical wavelength band while reducing optical loss and enhancing conversion efficiency.

Implementation Method 1

an overcladding layer formed on at least a part of a surface of the optical waveguide core and having a refractive index lower than the optical waveguide core

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

The wavelength converter is produced by using an optical crystal or the like having a second-order non-linear effect

Methodology Applied

Scientific EffectSecond harmonic generation: Second Harmonic Generation

Implementation Method 3

a temperature control element that controls a temperature of the wavelength conversion element

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS20250314943A1Wavelength Converter

Publication Date: 2025.10.09 NT T INC

AI summary

Provided is a wavelength converter that receives signal light and generates difference frequency light having a wavelength different from the signal light, the wavelength converter including: an optical waveguide core; a substrate having a refractive index lower than the optical waveguide core with respect to the signal light; a wavelength conversion element that converts the wavelength of the signal light; an overcladding formed on at least a part of a surface of the optical waveguide core and having a refractive index lower than the optical waveguide core with respect to optical wavelengths of the signal light and control light multiplexed with the signal light; and a temperature control element that controls a temperature of the wavelength conversion element.