Passive Optical Alignment Using Fiber Stubs and Etched Trenches
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Solution Overview
Problem
The alignment of optical components to waveguides with high coupling efficiency remains a challenge in the photonics industry, requiring expensive active alignment equipment and slowing down the fabrication process due to the need for sub-micron resolution multi-stage axis systems.
Innovation Solution
The use of fiber stubs to passively align optical components to semiconductor substrates by etching trenches and grooves, allowing the fiber stubs to establish optical alignment between lenses and optical devices, thereby reducing the need for active alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If active alignment equipment with sub-micron resolution multi-stage axis system is used, then alignment precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces fiber stubs as intermediary elements that bridge the optical component and the semiconductor substrate. These stubs serve as alignment mediators that transmit the alignment information from the optical component to the substrate, enabling passive alignment without complex active alignment equipment. The fiber stubs act as a simple mediator that resolves the alignment problem through their geometric relationship with both components.
Solution Approach 2:
The patent replaces the complex mechanical active alignment system with a passive alignment mechanism based on fiber stubs. Instead of using multi-stage axis systems with cameras and adjustment mechanisms, the invention uses the inherent geometry and positioning of fiber stubs to achieve alignment. This substitution eliminates the need for complex mechanical equipment while maintaining alignment precision.
2Manufacturing precision
If active alignment process is used, then alignment precision is improved, but productivity deteriorates due to slower fabrication process
Solution Approach 1:
The patent implements preliminary action by pre-positioning the fiber stubs on the semiconductor substrate before mounting the optical component. The fiber stubs are arranged in advance to define the precise alignment positions, so that when the optical component is mounted, it automatically aligns with the substrate features. This eliminates the need for time-consuming active alignment adjustments during the fabrication process, thereby improving productivity while maintaining precision.
Solution Approach 2:
The fiber stub alignment system enables self-service alignment where the optical component automatically finds its correct position through the fiber stubs. The stubs serve as self-aligning features that guide the optical component into the correct orientation without requiring external alignment equipment or manual adjustment. This self-aligning mechanism significantly speeds up the fabrication process while ensuring consistent alignment precision.
3Productivity
If fiber stubs are used for passive alignment, then productivity is improved, but measurement precision requirements increase
Solution Approach 1:
The fiber stubs serve as intermediary alignment references that translate the positioning requirements into simple geometric relationships. Instead of requiring complex measurement systems, the stubs provide physical reference points that can be easily measured and positioned. The intermediary nature of the stubs simplifies the measurement process while enabling high-precision alignment through their well-defined geometric relationship with both the optical component and substrate.
Data Source
AI summary
Embodiments herein include an optical system that passively aligns an optical component (e.g., a fiber array connector, lens array, lens body, etc.) with a semiconductor substrate using trenches that mate with optical fiber stubs. In one embodiment, the trenches are etched into the semiconductor substrate which provides support to optical devices (e.g., lasers, lens arrays, photodetectors, etc.) that transmit optical signals to, or receive optical signals from, the optical component. An underside of the optical component is etched to include at least two grooves (e.g., V-grooves) for receiving optical fiber stubs. In one embodiment, the optical fiber stubs are a portion of optical fiber that includes the core and cladding but not the insulative jacket. Once the fiber stubs are attached to the grooves, the fiber stubs are disposed into the trenches in the semiconductor substrate thereby passively aligning the optical component to the optical device on the substrate.