Photonics Chip Light-Source Structures with Edge-Coupler Alignment Detection
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Solution Overview
Problem
Misalignment between the edge coupler and the core of the optical fiber in photonics chips leads to light loss, degrading the efficiency of light transfer.
Innovation Solution
A photonics chip structure with a semiconductor substrate and a back-end-of-line stack featuring non-overlapping metal features and a cavity for the light source, which uses metal features to redirect light for alignment detection and a machine learning model to analyze the light signature for precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional non-destructive testing techniques are used to image the optical fiber and edge coupler, then misalignment can be diagnosed, but light loss from misalignment degrades light transfer efficiency
Solution Approach 1:
The patent implements preliminary alignment detection by capturing images of the optical fiber and edge coupler before final assembly using X-ray tomography. This allows misalignment to be diagnosed and corrected in advance, preventing light loss during operation while maintaining high light transfer efficiency.
2Difficulty of detecting and measuring
If the edge coupler is positioned adjacent to metal features for light redirection, then alignment detection is enabled, but the non-overlapping relationship constrains structural design
Solution Approach 1:
The metal features in the back-end-of-line stack serve multiple functions: they provide structural support for the photonic integrated circuit and simultaneously act as light redirection elements for alignment detection. This multi-functionality enables alignment measurement capability while avoiding additional structural complexity.
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
Enhances light transfer efficiency by ensuring optimal alignment of the light source with the edge coupler, reducing light loss and enabling accurate, automated diagnosis of misalignment.
Implementation Method 1
redirecting a second portion of the light from a plurality of metal features adjacent to the edge coupler
Data Source
AI summary
Structures including a light source and an edge coupler, and methods of forming and using such structures. The structure comprises a semiconductor substrate and a back-end-of-line stack on the semiconductor substrate. The back-end-of-line stack includes a first dielectric layer, a first plurality of metal features in the first dielectric layer, a second dielectric layer on the first dielectric layer, and a second plurality of metal features in the second dielectric layer. The second plurality of metal features have a non-overlapping relationship with the first plurality of metal features. The structure further comprises an edge coupler adjacent to the first plurality of metal features and the second plurality of metal features.