Fiber Alignment Structure for Optical Die Coupling
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Solution Overview
Problem
Existing optical input/output (I/O) packaging techniques fail to precisely align optical fibers with optical dies due to factors like core position, epoxy shrinkage, and mechanical stress, leading to suboptimal alignment and increased insertion loss.
Innovation Solution
The optical device incorporates a fiber alignment structure with a first portion on the optical fiber and a second portion on the optical die, featuring alignment projections and holes for precise alignment, allowing for passive alignment with high accuracy and stability, even at cryogenic temperatures, using 3D printing or etching techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If V-grooves or fiber array units attached to an optical die with adhesives are used, then the optical fiber can be connected to the optical die, but the alignment precision deteriorates due to epoxy shrinkage and manufacturing tolerances
Solution Approach 1:
The patent introduces a fiber alignment structure as an intermediary component between the optical fiber and the optical die. This alignment structure includes alignment features (such as alignment holes or protrusions) that mechanically couple the fiber to the die while providing precise positional reference, thereby achieving accurate alignment without relying on adhesive stability alone
Solution Approach 2:
The alignment structure is pre-formed on either the fiber or the die with precise geometric features before the bonding process. This preliminary alignment structure ensures that when the components are joined, the core and waveguide are already positioned with high precision, eliminating the need for post-bonding alignment adjustments
2Ease of manufacture
If passive alignment process is used relying on manufacturing tolerances, then the alignment can be achieved without active adjustment, but the alignment precision deteriorates due to tolerance accumulation
Solution Approach 1:
Instead of relying on overall component tolerances, the patent introduces localized alignment features (such as precision-machined holes or protrusions) at specific critical locations. These local features provide high-precision reference points that define the relative position between fiber and die, concentrating the precision requirement in specific areas rather than across the entire assembly
3Measurement precision
If active alignment process is used relying on epoxy stability, then the alignment can be optimized during bonding, but the alignment precision deteriorates due to epoxy shrinkage and mechanical stress
Solution Approach 1:
The alignment structure is pre-formed with precise geometric features before the bonding process occurs. This preliminary structure establishes the alignment reference in advance, so that when epoxy is applied and cured, the alignment is already determined by the rigid mechanical features rather than being dependent on epoxy stability during the curing process
Data Source
AI summary
An optical device includes an optical fiber and an optical die connected to the optical fiber. The optical fiber includes a core layer, a cladding layer formed on the core layer, and a first portion of a fiber alignment structure formed on the cladding layer. The optical die includes a die main body, an optical waveguide located in the die main body, and a second portion of the fiber alignment structure formed on the die main body and mated to the first portion of the fiber alignment structure so as to align the core layer of the optical fiber with the optical waveguide.