Grating Coupler Segments with Inverted Curvature
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Solution Overview
Problem
Conventional grating couplers in photonics chips suffer from low efficiency, lack of compactness, and are not robust to fabrication variability, limiting their performance in applications such as LIDAR systems and silicon photonics phased arrays.
Innovation Solution
A grating coupler structure comprising multiple inclined segments with alternating curved sections, where each segment includes a first curved section and a second curved section with inverted curvature, optimized for improved coupling efficiency and robustness through precise material selection and patterning processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional grating coupler structures are used, then the device complexity is low, but the coupling efficiency is low and the footprint is large
Solution Approach 1:
The grating coupler is divided into multiple segments along its length, with each segment containing alternating curved and inverted curved sections. This segmentation allows independent optimization of each section's curvature to enhance coupling efficiency while maintaining overall structural manageability
Solution Approach 2:
The grating coupler incorporates sections with alternating curvatures (first curvature and inverted curvature) rather than straight or uniformly curved designs. This alternating curvature pattern optimizes light coupling by creating favorable phase matching conditions across different segments
2Reliability
If conventional grating coupler structures are used, then the manufacturing process is simple, but the tolerance to fabrication variations is poor
Solution Approach 1:
Different segments of the grating coupler have locally optimized curvature characteristics - some sections have first curvature while others have inverted curvature. This local variation in geometric properties allows the structure to compensate for fabrication variations in different regions, improving overall robustness
Solution Approach 2:
The design employs alternating curvature parameters (first curvature and inverted curvature) across different segments. By varying the curvature parameter sign and magnitude in different locations, the structure becomes less sensitive to absolute dimensional variations during fabrication
3Area of stationary object
If conventional grating coupler structures are used, then the layout area is large, but the structural simplicity is maintained
Solution Approach 1:
The alternating curved and inverted curved sections enable the grating coupler to achieve compact folding or bending configurations. This allows the optical path to be contained within a smaller footprint area while maintaining the necessary interaction length for efficient coupling
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
The proposed structure enhances coupling efficiency, reduces footprint, and increases tolerance to fabrication variations, resulting in improved performance and reliability for photonics chips.
Implementation Method 1
Grating couplers can direct laser pulses off-chip at a given emission angle or receive laser pulses
Data Source
AI summary
Structures including a grating coupler and methods of forming a structure that includes a grating coupler. The grating coupler includes segments that are spaced along a longitudinal axis. Each segment is inclined relative to the longitudinal axis. Each segment includes a first curved section having a first curvature and a second curved section having a second curvature that is inverted relative to the first curvature.