Optical Alignment Structure for Silicon Photonics Packaging
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Solution Overview
Problem
The challenge in silicon photonics device packaging lies in the large mode size mismatch between optical fibers and high-index contrast silicon sub-micron waveguides, requiring extremely accurate alignment and precise placement, which is difficult to achieve due to the tight tolerance and high fabrication costs associated with existing methods.
Innovation Solution
An optical alignment structure with a light redirection mechanism that redirects input optical light back to a detector for alignment, allowing for precise alignment of optical fibers to silicon waveguides using a microring resonator or Bragg grating, enabling standardization and high repeatability in the packaging process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional alignment methods are used to couple optical fibers to silicon waveguides, then alignment accuracy can be achieved, but the process complexity and fabrication cost increase significantly
Solution Approach 1:
The patent introduces an optical alignment structure as an intermediary component that mediates between the optical fiber and the silicon waveguide. This structure includes alignment marks and optical paths that facilitate precise alignment without requiring complex direct coupling methods, thereby reducing process complexity while maintaining alignment accuracy.
Solution Approach 2:
The patent replaces complex mechanical alignment systems with an optical-based alignment approach. By using optical paths, mirrors, and detectors to establish alignment marks and verify positioning, the system eliminates the need for intricate mechanical adjustment mechanisms, thus reducing device complexity while preserving measurement precision.
2Reliability
If tight alignment tolerance is enforced to compensate for mode size mismatch, then coupling efficiency improves, but manufacturing precision requirements and costs increase
Solution Approach 1:
The patent implements preliminary alignment actions by pre-defining alignment marks and optical paths during the fabrication process. The optical alignment structure is prepared in advance with specific geometric features that guide the alignment process, allowing for relaxed real-time tolerance requirements while maintaining high coupling efficiency through pre-established reference frameworks.
3Measurement precision
If complex alignment instruments are used to achieve precise fiber placement, then alignment accuracy improves, but the packaging cost and process time increase
Solution Approach 1:
The optical alignment structure enables self-alignment capabilities where the alignment marks and optical paths automatically guide the positioning process. The system uses inherent optical feedback through the alignment structure itself, eliminating the need for external complex alignment instruments and reducing both process time and cost while maintaining accuracy.
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 solution simplifies the alignment process, improves accuracy, and increases the yield of silicon photonics packaging by using the redirected light intensity to determine proper alignment, reducing the need for complex instruments and allowing for standardization of the packaging process.
Implementation Method 1
using a microring resonator or Bragg grating
Implementation Method 2
The light redirection mechanism may include a microring resonator coupled to the light carrying structure
Implementation Method 3
using a microring resonator or Bragg grating
Data Source
AI summary
In various embodiments, an optical alignment structure may be provided. The optical alignment structure may include a light carrying structure configured to receive an input optical light from an external light source. The optical alignment structure may further include a light redirection mechanism coupled to the light carrying structure. The light redirection mechanism may be configured to receive the input optical light from the light carrying structure. The light redirection mechanism may be further configured to redirect the input optical light back to the light carrying structure, the redirected input optical light configured to be detected by a detector for alignment of the optical alignment structure with the external optical source.