Optical Circuit Alignment Using Intensity Spot Detection
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Solution Overview
Problem
The alignment between multiple grating couplers and optical fibers in a fiber array is challenging when the fiber array is rotated, leading to suboptimal optical connections and increased coupling loss.
Innovation Solution
An alignment optical circuit with multiple grating couplers arranged on a line and optical sensors measuring optical intensity at specific spots along the grating couplers' arrangement direction, allowing for precise adjustment of the fiber array's orientation to align with the grating couplers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fiber array is used to align multiple SMFs and grating couplers simultaneously, then alignment efficiency is improved, but alignment precision deteriorates when the fiber array is rotated or deviated
Solution Approach 1:
The patent divides the alignment task into two stages: first align the fiber array to the substrate using the marker pattern, then individually adjust each fiber's position relative to its corresponding grating coupler. This segmentation allows the system to maintain both high productivity through batch alignment and high precision through individual adjustment capability
Solution Approach 2:
The patent introduces a marker pattern as an intermediary element between the fiber array and the grating couplers. This marker serves as a reference for initial alignment, enabling the fiber array to be positioned accurately before final individual fiber adjustments, thus resolving the contradiction between efficient bulk alignment and precise individual positioning
2Ease of operation
If multiple grating couplers are arranged at fiber array pitch, then simultaneous alignment is enabled, but coupling loss increases due to rotation and deviation
Solution Approach 1:
The patent employs optical sensors to detect the actual positions and orientations of the grating couplers, providing feedback information that is used to adjust the fiber array positioning. This closed-loop feedback mechanism ensures that fibers are aligned precisely with their corresponding grating couplers, minimizing coupling loss while maintaining ease of operation through automated adjustment
Solution Approach 2:
The patent implements adjustable and reconfigurable fiber array positioning mechanisms that can dynamically adapt to the actual positions of grating couplers. This dynamic adjustment capability allows the system to compensate for rotations and deviations, maintaining optimal coupling efficiency while preserving the ease of simultaneous alignment operation
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
Facilitates easy and precise alignment of multiple optical fibers with corresponding grating couplers, reducing coupling loss and ensuring optimal optical connections.
Implementation Method 1
a grating including grooves having a width of several hundred nanometers, caused to function as a grating coupler that radiates light upward and downward from an optical waveguide onto a substrate surface
Implementation Method 2
an optical sensor that is formed on the substrate and measures optical intensity at two light-receiving spots on a line along an arrangement direction of the plurality of grating couplers
Data Source
AI summary
An alignment optical circuit includes: a plurality of grating couplers that are formed on a substrate and arranged on a line; a plurality of optical waveguides that are connected to the plurality of grating couplers, respectively. Further, the alignment optical circuit includes an optical sensor that is formed on the substrate and measures optical intensity at a first light-receiving spot and a second light-receiving spot on a line along an arrangement direction of the plurality of grating couplers.