Temperature-Controlled Planar Optical Waveguide Refractive Index

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Solution Overview

Problem

Optical polymer waveguides face significant challenges in manufacturing complex and varying refractive indices, leading to high optical losses due to bend transition losses when geometry changes, such as tight bends or crossings, which restricts their design and functionality in densely populated optical PCBs.

Innovation Solution

The method involves changing the temperature of uncured waveguide material before, during, or after curing to create density and refractive index variations, applying asymmetric refractive index perturbations to both the core and cladding of the waveguide, particularly in curved sections, to compensate for changes in waveguide geometry and maintain consistent boundary conditions, thereby reducing bend transition losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If waveguide geometry changes (tight bends or crossings) are implemented to enable complex routing on optical PCBs, then routing flexibility and design complexity are improved, but bend transition losses increase causing signal expulsion and optical losses

Engineering Contradiction:

Improverouting flexibilityVSAvoidoptical losses

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent applies asymmetric refractive index perturbations specifically in curved sections of the waveguide, creating local variations in the core and cladding refractive indices. This local modification of optical properties compensates for geometry changes and reduces bend transition losses, allowing tight bends and complex routing without significant optical losses

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the temperature of uncured waveguide material before, during, or after curing to create density and refractive index variations. By controlling temperature parameters, the patent achieves arbitrary cross-sectional refractive index profiles that compensate for bend-induced mode redistribution and reduce optical losses in curved sections

Inventive Principle:

Principle #35Parameter changes

2Reliability

If arbitrary cross-sectional refractive index profiles are fabricated using temperature control methods, then optical losses are reduced and signal integrity is improved, but manufacturing process complexity increases

Engineering Contradiction:

Improvesignal integrityVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses temperature as an intermediary parameter to control the density and refractive index of uncured waveguide material. By manipulating temperature during the curing process, the patent achieves precise control over refractive index profiles without requiring complex post-fabrication processing steps

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent exploits the phase transition of uncured waveguide material during curing, where temperature changes induce density variations that translate to refractive index variations. This phase transition mechanism enables arbitrary refractive index profiling through controlled thermal processing

Inventive Principle:

Principle #36Phase transitions

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 allows for the fabrication of waveguides with arbitrary cross-sectional refractive index profiles, reducing optical losses and enabling more complex routing geometries on optical PCBs by minimizing signal expulsion during transitions between straight and curved sections, thus enhancing signal integrity and flexibility in waveguide design.

Implementation Method 1

the uncured waveguide material having a density dependent on the temperature thereof; changing the temperature of at least a portion of the uncured waveguide material to a second temperature

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

the planar optical waveguide having at least a portion of the cross-sectional refractive index profile controlled by heat conduction properties of the polymeric material when in the uncured state

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 3

curing the uncured waveguide material to form the planar optical waveguide

Methodology Applied

Scientific EffectCuring: Photopolymerisation

Data Source

PatentUS10698157B2Methods of forming waveguides utilizing temperature control

Publication Date: 2020.06.30 SEAGATE TECH LLC

AI summary

Disclosed are methods of making a planar optical waveguide, the method including depositing an uncured waveguide material on a substrate, the uncured waveguide material having a first temperature when deposited and the uncured waveguide material having a density dependent on the temperature thereof; changing the temperature of at least a portion of the uncured waveguide material to a second temperature before curing, after curing, during curing or any combination thereof; and curing the uncured waveguide material to form the planar optical waveguide.