Switchable Grating Couplers With Tunable Conformal Layer

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Solution Overview

Problem

Grating couplers in photonics chips are fixed optical elements with non-tunable performance, limiting their adaptability and efficiency in coupling optical signals between waveguides and optical fibers.

Innovation Solution

A grating coupler structure with a conformal layer made of a tunable material whose refractive index changes with applied voltage, allowing for adjustable and switchable coupling efficiency and reconfigurable transmission spectrum.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed grating coupler structure is used, then the device complexity is reduced, but the adaptability for different wavelengths is worsened

Engineering Contradiction:

Improvewavelength adaptabilityVSAvoidgrating coupler structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by making the grating coupler structure switchable between different configurations. The conformal layer can be selectively removed or modified to change the grating coupler's coupling characteristics, enabling the same physical structure to adapt to different wavelength requirements dynamically rather than being fixed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying the physical state or properties of the conformal layer through voltage application. The refractive index of the conformal layer changes in response to applied voltage, which directly alters the optical coupling parameters of the grating coupler, enabling wavelength adaptation without changing the underlying structure.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If multiple fixed grating couplers are used for different wavelengths, then the wavelength adaptability is improved, but the device complexity and area increase

Engineering Contradiction:

Improvemulti-wavelength operationVSAvoidchip area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent applies universality by designing a single grating coupler structure that can perform multiple wavelength-specific functions. By using a conformal layer with voltage-tunable properties, one grating coupler can be configured to operate at different wavelengths, replacing the need for multiple dedicated grating couplers for each wavelength.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the functionality of multiple wavelength-specific grating couplers into a single reconfigurable structure. The conformal layer acts as a unifying element that, when modified or switched, allows the same grating coupler to serve multiple wavelength functions that would otherwise require separate devices.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If a reconfigurable grating coupler with conformal layer is used, then the wavelength adaptability is improved, but the manufacturing precision requirements increase

Engineering Contradiction:

Improveswitchable coupling efficiencyVSAvoidconformal layer deposition

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by making the conformal layer's properties spatially or functionally differentiated through selective modification. Rather than requiring the entire conformal layer to have uniform precision, the ability to selectively remove or modify specific regions allows for more relaxed manufacturing tolerances in the deposition process, as long as the selective modification can be precisely controlled.

Inventive Principle:

Principle #3Local quality

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

Enables a single device to operate with optimal coupling efficiencies at different wavelengths and compensates for wavelength shifts, enhancing the adaptability and performance of photonics chips in handling multiple wavelengths.

Implementation Method 1

The conformal layer is composed of a tunable material having a refractive index that changes with an applied voltage

Methodology Applied

Scientific EffectElectro-optic effect: Electro-Optic Effects

Data Source

PatentUS10895689B2Switchable and reconfigurable grating couplers

Publication Date: 2021.01.19 GLOBALFOUNDRIES US INC

AI summary

Structures for a waveguide and methods of fabricating a structure for a waveguide. A grating coupler is formed that has an arrangement of grating structures. A conformal layer is arranged over the plurality of grating structures. The conformal layer is composed of a tunable material having a refractive index that changes with an applied voltage.