Reverse Ribbed Optical Waveguides in Glass for Tight Bends

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Solution Overview

Problem

Legacy optical waveguides on semiconductor packages face challenges in achieving high coupling efficiency, fabricating optical waveguides with low signal loss, and routing optical signals through bends and turns efficiently.

Innovation Solution

The formation of a reverse ribbed waveguide structure in a glass layer, utilizing UV femtosecond laser patterning and masked UV exposure, allows for tighter bends with minimal optical losses, enabling efficient optical coupling with photonic integrated circuits (PICs) through evanescent or direct lateral coupling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional optical waveguide structures are used on semiconductor packages, then fabrication is simpler, but coupling efficiency is low and signal loss is high

Engineering Contradiction:

Improvecoupling efficiencyVSAvoidfabrication complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent inverts the traditional waveguide structure by etching trenches into the glass substrate and filling them with core material, rather than building up rib structures on the surface. This reverse approach creates better optical confinement and coupling interfaces, significantly improving coupling efficiency while maintaining manufacturability through standard semiconductor fabrication processes

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent employs composite material structures by combining glass substrate with high-refractive-index core materials (such as silicon nitride or silicon oxide) filled into etched trenches. This composite approach optimizes both optical confinement for high coupling efficiency and compatibility with existing semiconductor manufacturing processes

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If optical waveguides are routed through bends and turns, then connectivity flexibility increases, but signal loss increases

Engineering Contradiction:

Improverouting flexibilityVSAvoidsignal loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent implements local quality optimization by creating regions of higher refractive index within the waveguide path at bend locations. The trench-filling process allows precise control of core material distribution, enhancing optical confinement exactly where needed in curved sections to minimize radiation losses while maintaining overall routing flexibility

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes physical parameters of the waveguide structure by controlling trench depth, width, and filling material refractive index. These parameter optimizations enable tight bends with minimal signal loss, achieving both routing flexibility and low energy loss by carefully tuning the optical confinement properties at different locations along the waveguide path

Inventive Principle:

Principle #35Parameter changes

3Area of stationary object

If tighter routing is implemented, then substrate space requirements decrease, but manufacturing precision requirements increase

Engineering Contradiction:

Improvesubstrate spaceVSAvoidetching precision

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical drilling or complex lithography approaches with a trench-etching-and-filling process that leverages standard semiconductor fabrication capabilities. This substitution enables precise control of waveguide geometry for tight routing while utilizing well-established manufacturing processes, reducing the need for extreme manufacturing precision beyond current industrial capabilities

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 facilitates tighter routing, reduces substrate space requirements, and increases the number of optical input/output connections, achieving efficient optical connectivity within semiconductor packages.

Implementation Method 1

utilizing UV femtosecond laser patterning

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

a core material disposed within the first trench and the second trench

Methodology Applied

Scientific EffectOptical waveguide: Waveguide (optics)

Implementation Method 3

enabling efficient optical coupling with photonic integrated circuits (PICs) through evanescent or direct lateral coupling

Methodology Applied

Scientific EffectEvanescent coupling:

Data Source

PatentUS12442979B2Optical waveguide formed within in a glass layer

Publication Date: 2025.10.14 INTEL CORP

AI summary

Embodiments described herein may be related to apparatuses, processes, and techniques directed an optical waveguide formed in a glass layer. The optical waveguide may be formed by creating a first trench extending from a surface of the glass layer, and then creating a second trench extending from the bottom of the first trench, then subsequently filling the trenches with a core material which may then be topped with a cladding material. Other embodiments may be described and/or claimed.