Aspherical Lens Structure for Si Waveguide Coupling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The coupling efficiency between Si waveguides and optical fibers is compromised due to variations in manufacturing of mode field conversion structures, leading to incomplete mode field coupling and radiation modes that deteriorate the coupling efficiency.
Innovation Solution
A lens structure body with a double-sided asymmetric aspherical shape is introduced, featuring specific refraction surface parameters and a support member to improve coupling efficiency, reduce spherical aberration, and minimize the optical system size by compensating for incomplete mode-field converters and reducing reflectance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mode field conversion structure such as a taper structure or grating structure is formed in the Si waveguide, then the coupling between Si waveguide and optical fiber is improved, but manufacturing variations cause incomplete mode field coupling and radiation modes that deteriorate coupling efficiency
Solution Approach 1:
A lens structure is introduced as an intermediary component between the Si waveguide and optical fiber to achieve mode field conversion. The lens structure includes a first lens portion with a first refractive surface and a second lens portion with a second refractive surface, which together transform the mode field from the Si waveguide to match the optical fiber mode field, thereby improving coupling efficiency while being less sensitive to manufacturing variations in the waveguide itself
Solution Approach 2:
The invention changes the approach from modifying the Si waveguide geometry (taper/grating structures) to using a separate lens structure with controllable refractive index and curvature parameters. By adjusting the lens structure parameters (refractive surfaces, radii of curvature), optimal mode field conversion can be achieved regardless of waveguide manufacturing variations
2Reliability
If multiple lenses are used to achieve effective mode field coupling, then coupling efficiency is improved, but the optical system size increases
Solution Approach 1:
The invention merges the mode field conversion function and focusing function into a single integrated lens structure. The first lens portion and second lens portion work together as one unit to both transform the mode field and focus the light onto the optical fiber, eliminating the need for separate conversion structures and reducing the overall optical system size while maintaining high coupling efficiency
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
The proposed lens structure enhances coupling efficiency between optical waveguides with different mode field diameters, improves spherical aberration, and reduces the number of lenses required, thereby downsizing the optical system while maintaining effective light transmission.
Implementation Method 1
a lens portion (105) having a first refraction surface (101) on an illuminant side and a second refraction surface (102) on an emission side
Data Source
AI summary
An embodiment lens structure body includes a microlens portion of double-sided asymmetric aspherical shape having a refraction surface on an illuminant side and a refraction surface on an emission side so as to be opposed to the refraction surface, and marker portions formed so as to be joined to both ends of the microlens portion in a direction perpendicular to an optical axis.