Back-to-Back Tapered Sections for Photonics Chip Stitching
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Solution Overview
Problem
Positional mismatches during reticle stitching in photonics chip fabrication lead to misalignment of waveguide cores at boundaries, resulting in performance degradation such as elevated insertion loss and increased back reflection.
Innovation Solution
The implementation of tapered waveguide cores with increasing width dimensions across boundaries, allowing for efficient light transmission and improved tolerance to misalignment due to back-to-back tapered sections that align and transfer light across the boundary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If reticle stitching is used to pattern large photonics chips, then manufacturing area and productivity are improved, but manufacturing precision deteriorates due to positional mismatches at boundaries
Solution Approach 1:
The waveguide core width parameter is changed dynamically across the boundary region. The tapered sections create a gradual width transition from the first waveguide core to the second waveguide core, allowing the structure to adapt to positional mismatches while maintaining optical performance. This parameter change enables the system to tolerate manufacturing variations introduced during reticle stitching.
2Reliability
If waveguide cores are aligned precisely across reticle boundaries, then performance is improved, but device complexity increases due to additional alignment mechanisms
Solution Approach 1:
The tapered waveguide core structure is applied locally only at the boundary regions where reticle stitching occurs, rather than throughout the entire chip. This localized approach addresses the specific problem of misalignment at boundaries while maintaining simple, standard waveguide structures in the bulk areas, thereby avoiding unnecessary complexity.
Solution Approach 2:
The tapered sections act as an intermediary structure between the first and second waveguide cores. These tapered regions serve as a transition zone that mediates the optical coupling between misaligned waveguide cores, enabling efficient light transmission without requiring complex active alignment mechanisms.
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 configuration reduces the impact of reticle stitching mismatches, enhances light transfer across boundaries, and increases tolerance to misalignment, thereby improving the performance and reliability of photonics chips.
Implementation Method 1
The first tapered section has a first width dimension that increases with increasing distance from the boundary, and the second tapered section has a second width dimension that increases with increasing distance from the boundary
Data Source
AI summary
Structures including a waveguide core and methods of fabricating a structure including a waveguide core. The structure comprises a photonics chip including a first chip region, a second chip region, a first waveguide core in the first chip region, and a second waveguide core in the second chip region. The first chip region adjoins the second chip region along a boundary. The first waveguide core includes a first tapered section, and the second waveguide core includes a second tapered section positioned across the boundary from the first tapered section. The first tapered section has a first width dimension that increases with increasing distance from the boundary, and the second tapered section has a second width dimension that increases with increasing distance from the boundary.