Waveguide Cladding Bevels for Thicker, Crack-Resistant Cores
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Solution Overview
Problem
Existing waveguide manufacturing processes face challenges in reducing the risk of cracking in cladding layers, which limits the thickness and optical performance of waveguide cores.
Innovation Solution
A reshaping process is applied to form bevel profiles at the edges of the cladding layer to reduce stress, allowing for a larger thickness of the waveguide core, which improves optical performance and manufacturing yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cladding layer is formed with large thickness to improve waveguide core thickness and optical performance, then the optical performance is improved, but the risk of cracking in the cladding layer increases
Solution Approach 1:
A bevel profile is formed at the edge of the cladding layer before depositing the waveguide core layer. This preliminary shaping action creates a stress-relief geometry that prevents cracking during subsequent core layer deposition, enabling the use of thicker cladding layers for improved optical performance without suffering from cracking issues.
2Reliability
If the waveguide core thickness is increased to improve optical confinement and reduce losses, then the optical performance is enhanced, but the manufacturing process becomes more complex due to cracking risks
Solution Approach 1:
The bevel profile is created in advance during cladding layer formation, before the waveguide core deposition process. This preliminary action eliminates the need for complex crack-prevention measures during core layer manufacturing, allowing thick core layers to be deposited using standard processes while achieving improved optical confinement and reduced losses.
Data Source
AI summary
In an embodiment, a method includes: depositing a waveguide cladding layer over a substrate, the substrate having a center portion in a cross-sectional view and an edge portion adjacent the center portion in the cross-sectional view; reshaping the waveguide cladding layer to form a bevel profile in the waveguide cladding layer over the edge portion of the substrate; forming a recess in the waveguide cladding layer; depositing a waveguide core layer in the recess and over the waveguide cladding layer, the waveguide core layer extending along the bevel profile of the waveguide cladding layer; and planarizing the waveguide core layer and the waveguide cladding layer to form a waveguide core, the waveguide core including a portion of the waveguide core layer in the recess.