Non-planar Grating Couplers for Expanded Emission Angles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional grating couplers in photonics chips have a restricted vertical field of view due to their planar construction, limiting the emission angle to +/-15 degrees, which restricts the application in LIDAR systems and silicon photonics phased arrays.
Innovation Solution
A structure comprising a waveguide core, a bend, and a grating coupler with grating structures positioned in a spaced relationship in a layer stack above the bend, allowing for a significant component of the emission angle to be parallel to the top surface, thereby enabling a substantially horizontal emission angle up to 30 degrees without mechanical rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a planar grating coupler structure is used, then the manufacturing is simple and compact, but the vertical field of view is restricted to +/-15 degrees
Solution Approach 1:
The patent transitions from a two-dimensional planar grating coupler to a three-dimensional non-planar structure by introducing vertical layering with multiple grating periods at different heights. This dimensional change enables the emission angle to extend beyond the conventional +/-15 degrees while maintaining a compact footprint, effectively resolving the contradiction between field of view and structural complexity.
2Adaptability or versatility
If the emission angle is increased beyond +/-15 degrees, then the field of view is improved, but the planar construction limitations are violated
Solution Approach 1:
The patent introduces curved or non-planar waveguide paths with controlled bending radii to redirect light at angles exceeding the planar limitation. The curved waveguide sections enable gradual angle transformation while maintaining optical confinement, allowing emission angles beyond +/-15 degrees without requiring a completely non-integrated approach.
3Adaptability or versatility
If a non-planar grating coupler is implemented, then the emission angle can be increased, but the manufacturing complexity increases
Solution Approach 1:
The patent divides the grating coupler into multiple discrete layers, each containing grating structures with specific periods and orientations. This segmentation allows independent optimization of each layer's function and simplifies the fabrication process by enabling standard semiconductor manufacturing techniques to be applied to each layer separately, then combining them through vertical stacking.
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 expands the emission angle range, enhancing the field of view for optical signals and enabling a more versatile antenna design for LIDAR systems and silicon photonics phased arrays without mechanical adjustments.
Implementation Method 1
Grating couplers are planar structures that direct laser pulses off-chip at a given emission angle
Data Source
AI summary
Structures including a grating coupler and methods of fabricating such structures. The structure includes a waveguide core, a bend, and a grating coupler coupled to the waveguide core by the bend. The grating coupler includes grating structures that are positioned with a spaced relationship in a layer stack above the bend.