Optical Filter Waveguide Design for Temperature Stability

Solution Overview

Problem

Existing optical filters in silicon photonics face challenges in reducing temperature dependency of characteristics due to errors in waveguide width, which affect the propagation of light modes and spectral shifts.

Innovation Solution

The method involves designing optical filters with multiple waveguides having sections of specific lengths based on differentiations of propagation constants with respect to temperature and width, using equations to optimize section lengths and improve tolerance, thereby reducing temperature-dependent changes in characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If waveguide widths are adjusted to optimize light mode propagation, then spectral characteristics improve, but temperature dependency increases due to manufacturing errors

Engineering Contradiction:

Improvespectral characteristicsVSAvoidtemperature dependency

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The waveguide is divided into multiple sections with different width values along the propagation direction. Each section has a specific width designed to compensate for temperature-induced spectral shifts. This segmentation allows the filter to maintain spectral characteristics across a wide temperature range by distributing the compensation function across multiple segments rather than relying on a single critical dimension.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the width parameter of the waveguide sections to optimize both spectral characteristics and temperature stability. By carefully selecting different width values for different sections, the design achieves a balance between achieving the desired spectral response and reducing sensitivity to temperature variations and manufacturing tolerances.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If multiple modes of light are propagated through waveguide sections, then filtering functionality improves, but sensitivity to width errors increases

Engineering Contradiction:

Improvefiltering functionalityVSAvoidwidth error sensitivity

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The waveguide is divided into multiple sections with different width values along the propagation direction. Each section has a specific width designed to compensate for temperature-induced spectral shifts. This segmentation allows the filter to maintain spectral characteristics across a wide temperature range by distributing the compensation function across multiple segments rather than relying on a single critical dimension.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the width parameter of the waveguide sections to optimize both spectral characteristics and temperature stability. By carefully selecting different width values for different sections, the design achieves a balance between achieving the desired spectral response and reducing sensitivity to temperature variations and manufacturing tolerances.

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 approach effectively suppresses temperature-dependent changes in optical filter characteristics, even when waveguide widths deviate from design values, maintaining spectral stability and reducing shift amounts to several picometers per Kelvin.

Implementation Method 1

two or more waveguides having four or more sections in which there are two or more modes of light propagating through the four or more sections

Methodology Applied

Scientific EffectOptical waveguide: Waveguide (optics)

Implementation Method 2

designing the lengths of the four or more sections based on differentiations of propagation constants of the sections with respect to a temperature and widths of the sections

Methodology Applied

Scientific EffectPropagation constant differentiation:

Data Source

PatentUS20250085462A1Optical filter, method of manufacturing optical filter, method of designing, design apparatus, and non-transitory computer-readable recording medium

Publication Date: 2025.03.13 SUMITOMO ELECTRIC INDUSTRIES LTD

AI summary

A method of manufacturing an optical filter is a method of manufacturing an optical filter including two or more waveguides having four or more sections in which a number of modes of light propagating through the four or more sections is two or more. The method includes designing lengths of the four or more sections, and forming the two or more waveguides based on the lengths of the four or more sections. The designing includes designing the lengths of the four or more sections based on differentiation of propagation constants of the sections with respect to a temperature and widths of the sections.