Adiabatic Coupling Between Waveguide Arrays
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Solution Overview
Problem
Conventional optical waveguide coupling techniques, such as grating and edge coupling, face challenges in broadband applications due to high loss and require precise alignment, which is costly and affects adiabatic coupling performance, making them unsuitable for mass production and wafer-level testing.
Innovation Solution
The implementation of a semiconductor device with a recessed portion on its surface, featuring a first array of optical waveguide cores and a second array of optical waveguide cores in an adiabatic coupling relationship, covered with optical waveguide cladding material, allowing for efficient optical fiber coupling without the need for glue attachment and enabling wafer-level testing and standard edge coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If grating coupling is used to couple light into waveguides, then light can exit from wafer surface facilitating wafer level testing, but loss over large wavelength range increases away from center design wavelength
Solution Approach 1:
The patent introduces a vertical dimension by creating a recessed portion in the wafer surface and placing a second array of waveguide cores above the first array. This three-dimensional arrangement enables adiabatic coupling between the arrays while maintaining wafer-level testing capability through the recessed structure.
Solution Approach 2:
The patent embeds the first array of waveguide cores within the recessed portion of the wafer, and places the second array of waveguide cores above it, creating a nested configuration. This allows adiabatic coupling between the nested arrays while preserving the wafer surface for testing.
2Loss of energy
If edge coupling is used to couple light into waveguides, then optical coupling performance can be improved, but wafer level testing is not available and optical quality edge finish is required
Solution Approach 1:
Instead of coupling at the wafer edge (two-dimensional surface coupling), the patent creates a vertical arrangement with waveguide cores at different heights within a recessed portion. This enables adiabatic coupling in the vertical dimension while maintaining access to the wafer surface for testing.
Solution Approach 2:
The patent divides the waveguide structure into two separate arrays: first array waveguide cores at the bottom of the recessed portion and second array waveguide cores above them. This segmentation enables independent optimization of each array while achieving adiabatic coupling between them.
3Loss of energy
If precise alignment techniques are used to improve adiabatic coupling performance, then coupling efficiency increases, but manufacturing cost and complexity increase
Solution Approach 1:
The patent combines the alignment function into the wafer fabrication process itself by creating the recessed portion and positioning the first array of waveguide cores during wafer-level manufacturing. This eliminates the need for separate, complex alignment steps that would be required with conventional edge coupling methods.
Solution Approach 2:
The alignment structure is prepared in advance during wafer fabrication, with the recessed portion and first array of waveguide cores pre-positioned before the second array is added. This preliminary action simplifies subsequent assembly and reduces manufacturing complexity.
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 facilitates low-cost, high-throughput production with precise alignment, reduced loss, and the ability to perform final testing at the wafer level, avoiding expensive assembly techniques and tolerances associated with traditional methods.
Implementation Method 1
Each optical waveguide core in the second array of optical waveguide cores is in an adiabatic coupling relationship with a corresponding optical waveguide core in the first array of optical waveguide cores
Data Source
AI summary
A method includes providing a semiconductor body comprising a surface with a recessed portion therein. The recessed portion includes a bottom surface. Optical waveguide cores in a first array of optical waveguide cores extend side-by-side at the bottom surface. The method further includes providing a second array of optical waveguide cores over the first array of optical waveguide cores. Optical waveguide cores in the second array of optical waveguide cores extend side-by-side. Each optical waveguide core in the second array of optical waveguide cores is in an adiabatic coupling relationship with a corresponding optical waveguide core in the first array of optical waveguide cores. The method also includes applying an optical waveguide cladding material over the second array of optical waveguide cores.