Grating-Based Laser Coupling in III-V to SOI Waveguides

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Solution Overview

Problem

The manufacturing process of hybrid lasers with III-V group chips and SOI chips is inefficient due to the need for bonding processes, which complicates the coupling of laser light between the active layer and the silicon waveguide, leading to increased time and complexity.

Innovation Solution

The use of first and second gratings between the active layer and the optical waveguide layer allows for the redirection of laser light, enabling direct formation of the optical waveguide layer and gratings without bonding, simplifying the manufacturing process and improving efficiency by coupling the laser light into the waveguide through propagation direction changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If bonding process is used to laminate III-V group chip and SOI chip, then coupling between active layer and silicon waveguide is achieved, but manufacturing complexity and time increase

Engineering Contradiction:
Improvecoupling efficiencyVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the bonding process from the manufacturing workflow by using a suspended substrate structure that allows the III-V group chip to be positioned and coupled to the silicon waveguide without requiring thermal bonding or other complex joining processes. The active layer is directly coupled to the waveguide through precise positioning on the suspended substrate, eliminating the need for bonding while maintaining coupling efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The manufacturing process is segmented into independent steps: first forming the silicon waveguide on the suspended substrate, then separately preparing the III-V group chip, and finally coupling them together without bonding. This segmentation allows each component to be optimized and manufactured independently, reducing overall manufacturing complexity while maintaining high coupling efficiency.

Inventive Principle:
Principle #1Segmentation

2Reliability

If bonding process is used to laminate III-V group chip and SOI chip, then coupling between active layer and silicon waveguide is achieved, but manufacturing time increases

Engineering Contradiction:
Improvecoupling efficiencyVSAvoidmanufacturing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The bonding process is extracted and replaced with a direct coupling method using the suspended substrate. The III-V group chip is positioned and coupled to the silicon waveguide through mechanical support and optical alignment without requiring time-consuming thermal bonding processes, significantly reducing manufacturing time while maintaining coupling efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The suspended substrate structure is prepared in advance with the silicon waveguide already formed and positioned. This preliminary preparation allows the III-V group chip to be directly coupled without requiring time-consuming alignment and bonding steps during the final assembly, reducing overall manufacturing time while ensuring high coupling efficiency.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If direct formation of optical waveguide layer and gratings is used, then manufacturing process is simplified, but light coupling efficiency may be affected

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidlight coupling efficiency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent uses diffraction gratings that redirect light in the vertical dimension (perpendicular to the waveguide plane) to achieve coupling. The gratings convert light propagating parallel to the active layer into light that couples vertically into the silicon waveguide, enabling efficient coupling without complex lateral alignment while maintaining manufacturing simplicity.

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

Solution Approach 2:

The diffraction gratings act as intermediaries between the active layer and the silicon waveguide. They receive light from the active layer, modify its propagation direction through diffraction, and couple it into the waveguide, thereby simplifying the overall coupling structure while maintaining high coupling efficiency without requiring complex bonding processes.

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 simplifies the manufacturing process, reduces time, and enhances the coupling efficiency of the III-V group chip and SOI chip, resulting in improved single mode yield and reduced energy loss, while maintaining high output power and efficiency.

Implementation Method 1

a first grating, configured to change a propagation direction of the laser light in a way that the laser light emitted from the active layer propagates in a direction substantially orthogonal to a length direction of the first grating and toward the second grating

Methodology Applied
Scientific EffectDiffraction: Diffraction Grating

Implementation Method 2

a second grating, configured to change a propagation direction of the laser light in a way that the laser light injecting into the second grating propagates in a direction substantially parallel to a length direction of the optical waveguide layer and can inject into the optical waveguide layer

Methodology Applied
Scientific EffectDiffraction: Diffraction Grating

Data Source

PatentEP3296778B1Light emitting device, optical module and manufacturing method thereof
Publication Date: 2023.06.21 HISENSE BROADBAND MULTIMEDIA TECH LTD
  • EP3296778B1 patent drawingFigure 1A~1B
  • EP3296778B1 patent drawingFigure 2~3
  • EP3296778B1 patent drawingFigure 4~5

AI summary

A light emitting device, an optical module and a manufacturing method thereof are disclosed. According to an example of the disclosure, the light emitting device may comprise an optical waveguide chip, a light emitting chip and a grating between the light emitting chip and the optical waveguide chip. The light emitting chip may emit laser light. The grating may couple the laser light emitted from the active layer into the optical waveguide chip in a way that the laser light is output along a length direction of the optical waveguide chip.