Triplex Waveguide Coupler Using Vertical Kerr Coupling

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Solution Overview

Problem

TriPlex waveguides exhibit low χ (3) optical nonlinearities, making it difficult to perform single photon or squeezed light generation, which hinders their use in quantum computing and optical communications.

Innovation Solution

A coupler is designed with a second silicon nitride waveguide having a greater thickness and depth than the first waveguide, acting as a platform for stronger χ (3) Kerr effect, enabling single photons or squeezed light generation in the second waveguide and coupling it into the first waveguide, which is a low-loss TriPlex waveguide.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If TriPlex waveguides are used for low loss transmission, then loss is reduced, but χ (3) optical nonlinearity is insufficient

Engineering Contradiction:

Improvetransmission lossVSAvoidχ (3) optical nonlinearity

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The system is divided into two separate waveguides: a first TriPlex waveguide optimized for low-loss transmission and a second waveguide with enhanced χ (3) nonlinearity. This segmentation allows each waveguide to be independently optimized for its specific function, resolving the contradiction between low loss and sufficient nonlinearity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A coupler acts as an intermediary component to transfer light between the second waveguide (where nonlinearity occurs) and the first waveguide (where low-loss transmission occurs). This mediator enables the system to benefit from both low loss and sufficient nonlinearity without requiring a single waveguide to simultaneously optimize both conflicting properties.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If a single waveguide is used for both nonlinearity and low loss, then device complexity is reduced, but performance is compromised

Engineering Contradiction:

Improvewaveguide structureVSAvoidquantum computing performance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The overall coupler system performs multiple functions: the second waveguide generates nonlinear optical effects, the coupler transfers light, and the first waveguide transmits light with minimal loss. This multi-functional design achieves superior quantum computing performance despite increased structural complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If the second waveguide is positioned deeper in the substrate, then χ (3) nonlinearity is enhanced, but coupling distance increases

Engineering Contradiction:

Improveχ (3) nonlinearityVSAvoidcoupling distance

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The solution transitions from horizontal coupling to vertical coupling by positioning the waveguides at different depths in the substrate. This dimensional change allows the second waveguide to be placed deeper for enhanced nonlinearity while maintaining effective coupling through vertical proximity rather than horizontal distance.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The coupler acts as an intermediary that enables efficient energy transfer between waveguides separated in the vertical dimension. This mediator facilitates coupling despite the depth difference, allowing the second waveguide to be positioned deeper for enhanced nonlinearity without excessively increasing coupling distance.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 coupler facilitates the use of low-loss TriPlex waveguides in quantum computing and optical communications by providing a mechanism for single photon and squeezed light generation, enhancing χ (3) Kerr non-linearity and improving light coupling efficiency.

Implementation Method 1

these waveguides do not exhibit a strong χ (3) nonlinearity, which is required for single photon or squeezed light generation

Methodology Applied

Scientific Effectχ (3) Kerr effect: Kerr Effect

Implementation Method 2

A distal portion of the second silicon nitride waveguide is adjacent to a proximal portion of the first silicon nitride waveguide to cause light to couple from the second silicon nitride waveguide into the first silicon nitride waveguide

Methodology Applied

Scientific EffectEvanescent field coupling:

Data Source

PatentEP4711840A1Coupler for a triplex waveguide

Publication Date: 2026.03.18 QUIX QUANTUM BV

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Figure 3A~3B
Figure 4A~4B

AI summary

A coupler for coupling single photons or squeezed light into a first silicon nitride waveguide of an optical circuit is described. The coupler comprises a silicon dioxide substrate; the first silicon nitride waveguide formed in the silicon dioxide substrate, wherein the first silicon nitride waveguide is formed in a distal end of the silicon dioxide substate, and a second silicon nitride waveguide formed in the silicon dioxide substate, wherein: the second silicon nitride waveguide is formed in a proximal end of the silicon dioxide substrate wherein a distal portion of the second silicon nitride waveguide is adjacent to a proximal portion of the first silicon nitride waveguide to cause light to couple from the second silicon nitride waveguide into the first silicon nitride waveguide.