Grating Couplers with Perturbed Waveguides for Optical Signal Transmission

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Solution Overview

Problem

Conventional copper data channels face signal attenuation and crosstalk due to radiated electromagnetic energy, which are only modestly improved by existing techniques like equalization, coding, and shielding, and lack scalability.

Innovation Solution

The use of grating couplers with perturbed waveguides in semiconductor photonics, which vary in width along their length and include discrete scatterers, to enhance coupling efficiency and reduce mode-mismatch between optical fibers and grating couplers, enabling improved optical signal transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional copper data channels are used, then existing infrastructure can be maintained, but signal attenuation and crosstalk occur due to radiated electromagnetic energy

Engineering Contradiction:
Improvesignal qualityVSAvoidsignal attenuation
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent replaces copper electrical channels with optical waveguide channels, substituting electromagnetic signal transmission through conductors with optical signal transmission through dielectric waveguides. This fundamental substitution eliminates the radiated electromagnetic energy problems inherent in copper channels, achieving superior signal quality and reduced attenuation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the transmission medium parameter from electrical conductor to optical waveguide, and changes the signal type from electrical to optical. This parameter change enables transmission over longer distances with lower attenuation and without the crosstalk issues of copper channels.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If equalization, coding, and shielding techniques are applied to copper channels, then signal quality improves modestly, but power consumption and system complexity increase considerably

Engineering Contradiction:
Improvesignal qualityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent eliminates the need for complex equalization, coding, and shielding techniques by substituting copper channels with optical waveguides. The inherent properties of optical waveguides provide superior signal integrity without requiring additional complexity-mitigating technologies.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent converts the fundamental difference between electrical and optical transmission from a potential disadvantage into a benefit. The isolation properties of optical waveguides, which are physically distinct from electrical conductors, naturally prevent the radiated energy and crosstalk problems that would otherwise require complex mitigation techniques.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If equalization, coding, and shielding techniques are applied to copper channels, then signal quality improves modestly, but power consumption increases considerably

Engineering Contradiction:
Improvesignal qualityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces power-hungry electrical signal transmission through copper with optical signal transmission through waveguides. This substitution eliminates the need for power-intensive equalization, coding, and shielding techniques, achieving energy efficiency while maintaining superior signal quality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Productivity

If conventional grating couplers are used, then optical coupling can be achieved, but coupling efficiency is limited due to mode-mismatch between optical fibers and grating couplers

Engineering Contradiction:
Improvecoupling efficiencyVSAvoidoptical losses
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent applies local quality by introducing discrete scatterers at specific locations along the waveguide and varying the waveguide width locally. These localized modifications create controlled scattering that transforms the guided mode into a radiative mode better matched to the optical fiber, improving coupling efficiency and reducing optical losses.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the waveguide geometry parameter by varying the width along the length of the waveguide. This parameter change, combined with the introduction of discrete scatterers, transforms the mode profile to achieve better matching with the optical fiber mode, thereby improving coupling 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

This approach significantly improves coupling efficiency by matching the optical mode to the fiber mode, reducing optical losses and enhancing scalability beyond conventional copper links.

Implementation Method 1

grating couplers incorporating perturbed waveguides... vary in width along their length and include discrete scatterers, to enhance coupling efficiency

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

include discrete scatterers, to enhance coupling efficiency and reduce mode-mismatch between optical fibers and grating couplers

Methodology Applied
Scientific EffectScattering: Scattering

Data Source

PatentEP3351983B1Method and system for grating couplers incorporating perturbed waveguides
Publication Date: 2022.03.23 LUXTERA INC
  • EP3351983B1 patent drawingFigure 1A
  • EP3351983B1 patent drawingFigure 1B
  • EP3351983B1 patent drawingFigure 1C

AI summary

Methods and systems for grating couplers incorporating perturbed waveguides are disclosed and may include in a semiconductor photonics die, communicating optical signals into and/or out of the die utilizing a grating coupler on the die, where the grating coupler comprises perturbed waveguides. The perturbed waveguides may comprise a variable width along their length. The grating coupler may comprise a single polarization grating coupler comprising perturbed waveguides and a non-perturbed grating. The grating coupler may comprise a polarization splitting grating coupler (PSGC) that includes two sets of perturbed waveguides at a non-zero angle, or a plurality of non-linear rows of discrete shapes. The PSGC may comprise discrete scatterers at an intersection of the sets of perturbed waveguides. The grating couplers may be etched in a silicon layer on the semiconductor photonics die or deposited on the semiconductor photonics die. The grating coupler may comprise individual scatterers between the perturbed waveguides.