Trench Reflector Structure for Photonics Chip Coupling Efficiency
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Solution Overview
Problem
The process flow for forming a distributed Bragg reflector in photonics chips is complex, necessitating improved structures and methods for reflectors in photonics chips.
Innovation Solution
A structure for a photonics chip comprising a dielectric layer with trenches and a reflector layer on sidewalls, enhanced by a metamaterial structure, which includes a reflector layer inside the trenches and sections on the sidewalls, improving coupling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a distributed Bragg reflector is used to enhance coupling efficiency, then the coupling efficiency is improved, but the process flow complexity increases
Solution Approach 1:
The reflector is segmented into multiple discrete layers including a first dielectric layer, a reflector layer with trenches, and a second dielectric layer. This segmentation allows each layer to be formed using separate process steps, simplifying the overall fabrication process while maintaining the optical reflection functionality of a distributed Bragg reflector.
Solution Approach 2:
The reflector layer is selectively positioned only in specific regions where trenches are formed in the first dielectric layer, rather than forming a continuous uniform layer. This local quality approach reduces material usage and simplifies the deposition process while maintaining reflection efficiency at the required locations.
2Reliability
If a distributed Bragg reflector with vertical stack of multiple layers is formed, then the coupling efficiency is enhanced, but the manufacturing complexity increases
Solution Approach 1:
Trenches are pre-formed in the first dielectric layer before depositing the reflector layer. This preliminary action defines the exact regions where reflective material is needed, allowing the reflector layer to be deposited conformally only in those areas, thereby simplifying subsequent manufacturing steps.
Solution Approach 2:
The reflector layer is nested within the trenches of the first dielectric layer, with portions of the reflector layer positioned inside the trenches and portions on the sidewalls. This nested structure achieves the complex optical functionality of a distributed Bragg reflector through a simplified layered approach.
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 the performance of grating couplers by improving coupling efficiency and absorption in photodetectors, suitable for applications in data communication and LiDAR systems.
Implementation Method 1
a reflector including a dielectric layer on a semiconductor substrate, a plurality of trenches in the dielectric layer, and a reflector layer. Each trench includes a plurality of sidewalls, and the reflector layer includes a portion on the sidewalls of each trench
Data Source
AI summary
Structures for a photonics chip that include a reflector and methods of forming such structures. The structure comprises a reflector including a dielectric layer on a semiconductor substrate, a plurality of trenches in the dielectric layer, and a reflector layer. Each trench includes a plurality of sidewalls, and the reflector layer includes a portion on the sidewalls of each trench. The structure further comprises a photonic component over the reflector.