MEMS Steering Mirrors for Grating Coupler Angle Compensation

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Solution Overview

Problem

Existing optical communication systems face inefficiencies due to process variations in optical grating couplers, which affect center wavelength and angle of incidence, leading to suboptimal performance in devices employing wavelength-division multiplexing.

Innovation Solution

Incorporation of an adjustable microelectromechanical system (MEMS) mirror to compensate for variations in center wavelength and angle of incidence by dynamically adjusting the angle of light impinging on the grating coupler, using electrostatic actuators controlled by a feedback mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If process variations in optical grating couplers are present, then manufacturing precision is reduced, but device complexity increases when adding compensation mechanisms

Engineering Contradiction:
Improvegrating coupler fabrication precisionVSAvoidoptical assembly complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent employs a MEMS mirror that can dynamically adjust its tilt angle to compensate for angle of incidence variations caused by grating coupler fabrication tolerances. The mirror's position and orientation are adjustable to optimize coupling efficiency despite manufacturing variations in the grating coupler structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the angle of incidence parameter by tilting the MEMS mirror to compensate for deviations from the optimal coupling angle. This parameter adjustment allows the system to maintain efficient light coupling into the waveguide despite variations in grating coupler fabrication.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If fixed optical components are used, then device complexity is reduced, but adaptability to wavelength variations deteriorates

Engineering Contradiction:
Improvewavelength tuning capabilityVSAvoidoptical component adjustability
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The MEMS mirror provides dynamic adjustability in a compact form factor, enabling wavelength tuning and angle compensation without requiring complex mechanical positioning systems. The mirror can be electronically controlled to adapt to different wavelengths and coupling conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent replaces bulky mechanical positioning devices with a compact MEMS mirror that achieves similar adaptability through micro-electromechanical actuation. This substitution maintains wavelength tuning capability while significantly reducing device complexity and size.

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

3Volume of moving object

If traditional optical assemblies are used, then manufacturing simplicity is maintained, but miniaturization is limited

Engineering Contradiction:
Improveoptical assembly sizeVSAvoidassembly integration difficulty
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The patent merges the grating coupler, waveguide, and MEMS mirror into a single integrated photonic device structure. This consolidation achieves miniaturization by eliminating the need for separate mounting and alignment of traditional discrete optical components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The MEMS mirror serves as an intermediary element that enables compact integration by providing the necessary optical adjustment function within the miniaturized photonic device, bridging the gap between the light source and waveguide coupling requirements.

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

This approach allows for miniaturization and cost reduction of integrated optical assemblies while enhancing their operational efficiency and tolerance to fabrication variations, making them suitable for data communications transceivers.

Implementation Method 1

a microelectromechanical systems (MEMS) mirror configured to receive the beam of light from the lens and redirect it towards the grating coupler

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

using electrostatic actuators controlled by a feedback mechanism

Methodology Applied
Scientific EffectElectrostatic actuation: Electrostatics

Data Source

PatentEP3410166B1MEMS steering mirrors for applications in photonic integrated circuits
Publication Date: 2025.07.02 GOOGLE LLC
  • EP3410166B1 patent drawingFigure 1A~1B
  • EP3410166B1 patent drawingFigure 2
  • EP3410166B1 patent drawingFigure 3

AI summary

An integrated optical assembly includes an optics mount. The optics mount has disposed thereon a light source for providing a beam of light and a lens configured to focus the beam of light. The integrated optical assembly includes a photonic integrated circuit (PIC) mechanically coupled to the optics mount. The PIC has disposed thereon a grating coupler for receiving the beam of light and coupling the beam of light into a waveguide. The integrated optical assembly includes a microelectromechanical systems (MEMS) mirror configured to receive the beam of light from the lens and redirect it towards the grating coupler. A position of a reflective portion of the MEMS mirror is adjustable to affect an angle of incidence of the beam of light on the grating coupler.