Grating Coupler Offset Inlets Disambiguate Beam Motion
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Solution Overview
Problem
Existing grating couplers face ambiguities in determining the motion of an optical beam and changes in its incident angle, which complicates maintaining high coupling efficiency and alignment.
Innovation Solution
The use of offset inlets and varied grating periodicity in grating couplers allows for disambiguation of beam motion and incident angle changes, enhancing sensitivity to alignment by monitoring radiation signals from multiple waveguides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single inlet is used in a grating coupler, then the structure is simple, but the ability to distinguish beam motion from incident angle changes is lost
Solution Approach 1:
The patent divides the single inlet into multiple inlets (first inlet and second inlet) with different offsets relative to the grating. This segmentation allows the system to receive radiation from multiple spatial positions, enabling differentiation between beam motion and angle changes through comparative signal analysis from each inlet.
Solution Approach 2:
The patent introduces a spatial offset dimension by positioning inlets at different locations relative to the grating structure. The first inlet is offset in a first direction while the second inlet is offset in a second direction, creating a multi-dimensional spatial arrangement that provides additional information for beam alignment detection.
2Measurement precision
If inlets are offset in multiple directions, then beam alignment sensitivity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies different offset configurations to different inlets, where each inlet has a specific offset direction and distance tailored to its function. The first inlet has a first offset and the second inlet has a second offset, creating localized quality variations that optimize each inlet's contribution to beam alignment detection while managing manufacturing complexity.
3Measurement precision
If grating periodicity is varied across regions, then incident angle detection capability is enhanced, but device complexity increases
Solution Approach 1:
The patent implements a grating structure where different regions have different periodicities. A first region has a first periodicity and a second region has a second periodicity, allowing each region to be optimized for detecting specific incident angle characteristics. This local variation in grating properties enhances the overall incident angle detection capability while maintaining a systematic structure.
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 improves the grating coupler's sensitivity to beam alignment, enabling more precise coupling of optical radiation into multiple waveguides and maintaining high coupling efficiency by distinguishing between beam motion and angle changes.
Implementation Method 1
one or more gratings... arranged to couple radiation incident on the grating into a plurality of optical waveguides
Data Source
Figure 1-1~1-2
Figure 1-3~2-1
Figure 2-2~2-3
AI summary
Apparatus and methods relating to coupling radiation from an incident beam (1-122) into a plurality of waveguides (1-, 2-, 3-212a...e) with a grating coupler (1-, 2-, 3-210) are described. A grating coupler (1-, 2-, 3-210) can have offset receiving regions and grating portions with offset periodicity to improve sensitivity of the grating coupler (1-, 2-, 3-210) to misalignment of the incident beam (1-122).