Tunable Photonic Couplers for Manufacturing Error Correction

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Solution Overview

Problem

Existing photonic couplers in silicon photonics suffer from manufacturing imperfections that lead to errors in the mixing ratio of electromagnetic energy transfer, despite being designed as 50/50 beam splitters.

Innovation Solution

Incorporation of an electro-optic device with a voltage-dependent index of refraction to tune the effective coupling length, allowing adjustment of the mixing ratio by applying a bias voltage to correct performance errors and achieve desired splitting ratios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If photonic couplers are designed as 50/50 beam splitters using standard semiconductor processing, then manufacturing is simplified and production efficiency is improved, but manufacturing imperfections cause errors in the mixing ratio of electromagnetic energy transfer

Engineering Contradiction:

Improveproduction efficiencyVSAvoidmixing ratio accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent changes the physical parameter of the coupling region by introducing an electro-optic material whose refractive index can be dynamically adjusted via applied voltage. This allows the mixing ratio to be tuned after manufacturing, compensating for fabrication imperfections while maintaining standard semiconductor processing benefits

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent transforms a static photonic coupler into a dynamic device by incorporating voltage-controlled electro-optic elements. The mixing ratio can be adjusted in real-time through applied bias voltages, enabling post-manufacturing calibration to correct for manufacturing variations

Inventive Principle:

Principle #15Dynamics

2Manufacturing precision

If the physical length of the coupling region is increased to improve mixing ratio accuracy, then manufacturing precision is improved, but device length increases leading to larger device footprint and reduced integration density

Engineering Contradiction:

Improvemixing ratio accuracyVSAvoiddevice length

Core Design Contradiction:

Manufacturing precisionVSLength of moving object

Solution Approach 1:

Instead of increasing physical length to improve accuracy, the patent changes the refractive index parameter of the coupling region using electro-optic materials. This allows precise control of the mixing ratio without extending the physical device length, maintaining compact integration

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite structures combining standard silicon waveguides with electro-optic materials (such as lithium niobate or polymer electro-optic layers). This composite approach enables precise mixing ratio control through the electro-optic material's voltage-dependent refractive index while keeping the overall device compact

Inventive Principle:

Principle #40Composite materials

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 solution enables precise control over the mixing ratio of electromagnetic energy transfer, correcting manufacturing-induced errors and enabling tunable performance of photonic couplers.

Implementation Method 1

an electro-optic device in the coupling region that includes an index of refraction that is a first function of an applied voltage

Methodology Applied

Scientific EffectElectro-optic effect: Electro-Optic Effects

Data Source

PatentUS20250237810A1Tunable photonic couplers for electronic/photonic systems and methods of forming the same

Publication Date: 2025.07.24 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

An embodiment photonic coupler may include a first input waveguide, a second input waveguide, a first output waveguide, a second output waveguide, a coupling region in which electromagnetic fields associated with two or more of the first input waveguide, the second input waveguide, the first output waveguide, and the second output waveguide are overlapping with one another, and an electro-optic device in the coupling region that includes an index of refraction that is a first function of an applied voltage. The coupling region may have an effective coupling length, along an optical propagation direction, which is a second function of a product of a physical length of the coupling region multiplied by the index of refraction of the electro-optic device. A mixing ratio of electromagnetic energy transferred between the input and output waveguides, due to evanescent coupling, may be controlled by adjusting the voltage applied to the photonic coupler.