Multilayer Signal Routing with Magneto-Optical Isolation

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Solution Overview

Problem

Existing photonic components in data centers, such as switches, circulators, and isolators, face challenges with high insertion losses and unsatisfactory isolation ratios, making them unsuitable for efficient data flow and integration into photonic integrated circuits (PICs).

Innovation Solution

A multilayer signal routing structure comprising dielectric waveguide layers with a magneto-optical material, utilizing an external magnetic field to guide electromagnetic signals in a predetermined direction while suppressing others, achieving negligible energy loss and low power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional waveguiding solutions are used for signal routing, then the structure is simple and easy to manufacture, but the insertion loss is high and the isolation ratio is unsatisfactory

Engineering Contradiction:
Improveinsertion lossVSAvoidstructure complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent transitions from planar 2D waveguide routing to 3D multi-layer vertical routing. Multiple waveguide layers are stacked vertically with selective coupling between layers, enabling signals to route in three dimensions. This vertical dimension allows multiple signal paths to coexist without interfering with each other, reducing insertion loss while maintaining compact footprint.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The signal routing function is divided into multiple independent layers, each handling specific signal routes. Waveguides in different layers can be independently optimized for their respective functions. This segmentation allows each layer to be designed for minimal loss while the overall system achieves high isolation through vertical separation of signal paths.

Inventive Principle:
Principle #1Segmentation

2Reliability

If magneto-optical materials are integrated into the waveguide structure, then the isolation ratio improves and signal routing control enhances, but the manufacturing complexity increases

Engineering Contradiction:
Improveisolation ratioVSAvoidintegration complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Magneto-optical materials are integrated as intermediate layers positioned between waveguide layers, nested within the existing multi-layer waveguide structure. This nesting approach allows the magneto-optical functionality to be incorporated without fundamentally redesigning the waveguide system, maintaining compatibility with standard semiconductor manufacturing processes while achieving high isolation ratios.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

Magneto-optical materials are selectively placed only in specific intermediate layers where signal isolation and routing control are most needed, rather than throughout the entire structure. This localized integration minimizes the impact on manufacturing complexity while maximizing the isolation performance where it matters most for signal routing control.

Inventive Principle:
Principle #3Local quality

3Area of stationary object

If multiple waveguide layers are stacked vertically for 3D routing, then the footprint is reduced and routing efficiency improves, but the alignment precision requirements increase

Engineering Contradiction:
ImprovefootprintVSAvoidalignment precision
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

By moving routing operations to the vertical dimension through multi-layer stacking, the horizontal footprint is dramatically reduced. The vertical separation between layers provides inherent isolation that compensates for moderate alignment tolerances, allowing compact integration without requiring extremely precise lateral alignment while maintaining routing efficiency.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

The proposed structure enables efficient photonic switches, circulators, and isolators with minimal energy loss and easy integration into PICs, requiring no complex manufacturing steps and maintaining performance across various MO materials by adjusting geometric dimensions.

Implementation Method 1

The at least one intermediate layer (20) comprises a magneto-optical material, MO, and/or the at least two cover layers (30) comprise a magneto-optical material, MO

Methodology Applied
Scientific EffectMagneto-optical effect: Magneto-Optic Effects

Implementation Method 2

An external magnetic field is applied to the multilayer signal guide structure (100), whereby a transverse magnetic mode, TM mode, and/or a transverse electric mode, TE mode, of an electromagnetic signal introduced into the multilayer signal guide structure (100) experiences a change in its electromagnetic field profile

Methodology Applied
Scientific EffectFaraday effect: Faraday Effect

Data Source

PatentEP4592741A1Multi-layer signal routing structure and method for operating a multi-layer signal routing structure
Publication Date: 2025.07.30 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP4592741A1 patent drawingFigure 1~2
  • EP4592741A1 patent drawingFigure 3A~3B
  • EP4592741A1 patent drawingFigure 4~5

AI summary

Described is a multilayer signal-guiding structure comprising: a plurality of layers, wherein the plurality of layers comprises at least two waveguide layers which extend along an extension direction and which serve to couple in an electromagnetic signal, and at least one intermediate layer arranged between the at least two waveguide layers; at least two covering layers, wherein the at least two waveguide layers are arranged partially or completely between the at least two covering layers, wherein the at least one intermediate layer comprises a magneto-optical material, MO, and/or the at least two covering layers comprise a magneto-optical material, MO. Furthermore, a method for operating a multilayer signal-guiding structure is described.