Optical Waveguide Recess for Reduced Coupling Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical systems experience significant optical loss due to the distance between light sources and waveguide facets in planar optical devices, as the facet shelf limits the proximity of light sources to the waveguide facets, necessitating a reduction in facet shelf width to minimize this loss.
Innovation Solution
A method involving the formation of waveguide and facet masks on a device precursor to create a recess or shelf, allowing for the reduction or elimination of the facet shelf width, enabling closer alignment of light sources with waveguide facets by etching techniques, and using protective masks to maintain facet and waveguide integrity during processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a traditional planar optical device structure with facet shelf is used, then the waveguide facet is protected during fabrication, but the light source must be positioned at a greater distance from the waveguide facet, resulting in increased optical loss
Solution Approach 1:
The patent introduces a recess structure that extends vertically downward from the facet shelf into the substrate, creating a three-dimensional configuration. This allows the light source to be positioned in the recess at a horizontal distance of less than 10 micrometers from the waveguide facet while maintaining proper optical alignment, thereby reducing optical loss without compromising fabrication protection
Solution Approach 2:
The recess structure nests within the substrate beneath the facet shelf, creating a hierarchical arrangement where the light source is embedded in the recess. This nested configuration allows the light source to be positioned close to the waveguide facet horizontally while the facet shelf remains above to provide fabrication protection, effectively resolving the contradiction between proximity and protection
2Length of moving object
If the facet shelf width is reduced to allow closer light source positioning, then optical loss is reduced, but the waveguide facet becomes more vulnerable to damage during fabrication processes
Solution Approach 1:
The invention separates the protection function from the positioning function by creating a recess structure. The facet shelf maintains its full width for fabrication protection, while the recess extends vertically downward to enable close light source positioning. This dimensional separation allows both contradictory requirements to be satisfied simultaneously
Solution Approach 2:
The structure is segmented into distinct functional zones: the facet shelf provides protection during fabrication, the recess accommodates the light source at close horizontal distance, and the vertical walls of the recess provide structural support. This segmentation allows each component to optimize its specific function without compromising the other
3Length of moving object
If a recess structure is created to position the light source closer to the waveguide facet, then optical alignment is improved, but the fabrication process becomes more complex
Solution Approach 1:
The recess structure is formed as an integral part of the substrate during the initial fabrication stages, before the waveguide and facet shelf are created. This preliminary formation of the recess simplifies subsequent processing steps and allows the light source to be positioned accurately without requiring complex alignment procedures in later stages
Data Source
AI summary
A method of forming an optical device includes forming a waveguide mask on a device precursor. The device precursor includes a waveguide positioned on a base. The method also includes forming a facet mask on the device precursor such that at least a portion of the waveguide mask is between the facet mask and the base. The method also includes removing a portion of the base while the facet mask protects a facet of the waveguide. The portion of the base that is removed can be removed such that a recess is defined in the base and/or a shelf is defined on the device precursor. A light source such as an optical fiber or laser can be received in the recess and/or positioned over the shelf such that the light source is optically aligned with the facet of the waveguide.