Optical Waveguide Asymmetric Core for Coupling Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical waveguide devices face challenges in achieving high optical coupling efficiency between silicon and polymer waveguides, particularly due to positional shifts of the polymer waveguide core, which can lead to reduced coupling efficiency.
Innovation Solution
The optical waveguide device incorporates a substrate with a first waveguide and a second waveguide, where the second waveguide features a core with a bottom surface in contact with the substrate and a convex surface connected to it. The core's thickness gradually decreases from the center to the edges in a transverse cross-sectional view, enhancing optical coupling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a substantially circular core is used in the polymer waveguide, then the optical coupling with the silicon waveguide can be achieved, but the coupling efficiency is highly sensitive to positional shifts of the core
Solution Approach 1:
The patent changes the core shape from a substantially circular symmetric shape to an asymmetric shape where the thickness gradually decreases from the center toward one end. This asymmetric configuration creates a distinct thickness gradient that reduces sensitivity to positional misalignment, as the optical coupling is optimized across a broader range of positions rather than requiring precise centering.
Solution Approach 2:
The patent applies local quality by creating a thickness gradient within the core, where different regions have different thicknesses. The thicker central region provides strong optical confinement, while the gradually thinning edges create an adiabatic transition that enhances coupling robustness to positional variations.
2Reliability
If the core width is reduced to improve coupling, then the coupling efficiency increases, but the position shift tolerance decreases
Solution Approach 1:
The patent introduces a dynamic thickness profile that gradually changes from the center to the edge, creating an adaptive structure. This gradual thickness variation allows the optical mode to adaptively transition across the interface, providing both high coupling efficiency and tolerance to position shifts through the extended interaction length created by the tapered geometry.
3Ease of manufacture
If a conventional circular core is used, then the manufacturing process is simple, but the coupling efficiency varies significantly with manufacturing tolerances
Solution Approach 1:
The patent changes the geometric parameters of the core from a uniform circular cross-section to a shape with gradually varying thickness. This parameter change transforms the coupling characteristics, making the system less sensitive to manufacturing tolerances while maintaining compatibility with existing fabrication techniques such as spin coating and UV curing.
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 configuration allows for improved optical coupling efficiency between the waveguides, reducing variations in coupling efficiency among manufactured devices and facilitating easier alignment, even with slight positional deviations of the core.
Implementation Method 1
realizes low-loss optical coupling between the silicon waveguide and the polymer waveguide by adiabatic coupling
Implementation Method 2
realizes low-loss optical coupling between the silicon waveguide and the polymer waveguide by adiabatic coupling
Data Source
AI summary
An optical waveguide device includes a substrate, a first waveguide disposed on or in the substrate, and a second waveguide disposed on a first surface of the substrate, wherein the second waveguide includes a core and a cladding covering the core, wherein throughout an entirety of a predetermined region, a portion of the core overlaps the first waveguide when viewed from a direction normal to the first surface, in wherein the predetermined region, the core has a bottom surface in contact with the first surface and a convex surface connected to the bottom surface, and wherein the core includes a portion whose thickness gradually decreases from a widthwise center to widthwise ends in a transverse cross-sectional view.