Fiber Optic Adapter Alignment Using Segmented Ferrule Holders
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Solution Overview
Problem
Existing fiber optic connector designs with ganged ferrules face challenges in scaling to large arrays due to tight tolerance requirements, leading to increased complexity and cost, especially in aligning ferrules within a single housing.
Innovation Solution
An adapter assembly with novel alignment features, including grooves and projections, allows ferrule holders to be aligned in the X and Y directions without relying on side walls, using a plug to engage with the adapter and maintain alignment within 100 microns, reducing the need for precise true position tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If tight tolerance requirements are used for aligning ferrules within a single housing, then alignment precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The invention divides the alignment system into separate components: the adapter housing and the ferrule holder are segmented such that the ferrule holder contains its own alignment features (projections) that mate with corresponding features in the adapter. This segmentation allows each component to be manufactured independently with relaxed tolerances, eliminating the need for tight true position tolerances on the housing while maintaining overall alignment precision.
Solution Approach 2:
The ferrule holder acts as an intermediary component between the adapter housing and the ferrules. It carries alignment projections that directly engage with grooves in the adapter, serving as a mediator that establishes precise ferrule positioning without requiring the housing itself to have tight tolerances. This intermediary approach decouples the alignment function from the housing structure.
2Manufacturing precision
If tight tolerance requirements are used for aligning ferrules within a single housing, then alignment precision is improved, but manufacturing cost increases
Solution Approach 1:
By segmenting the alignment function into the ferrule holder's projections and the adapter's grooves, the invention allows each part to be manufactured with standard tolerances using conventional processes. This eliminates the need for expensive tight tolerance machining or inspection of the housing, significantly reducing manufacturing cost while maintaining alignment precision through the mateable projection-groove interface.
Solution Approach 2:
The ferrule holder with its alignment projections serves as a relatively simple, easily manufactured component that can be produced cost-effectively. Rather than investing in expensive housing manufacturing processes to achieve tight tolerances, the design uses a simpler ferrule holder structure that can be manufactured at lower cost while achieving the same alignment function.
3Quantity of substance
If large arrays of ferrule holders are manufactured within one housing, then fiber optic ferrule count increases, but true position tolerance requirements become more difficult to maintain
Solution Approach 1:
The invention segments the alignment function to the individual ferrule holder level, where each holder has its own projections. This allows large arrays of ferrule holders to be manufactured independently and then assembled into the adapter, with each unit self-aligning through its projections. The segmentation eliminates the cumulative true position tolerance stack-up that would occur if all ferrules were positioned relative to a single housing reference.
Solution Approach 2:
The alignment approach shifts from two-dimensional positioning within the housing plane to three-dimensional mateable features (projections fitting into grooves). This dimensional change provides mechanical constraint in multiple directions simultaneously, ensuring precise positioning of each ferrule holder regardless of array size, and eliminating the need to maintain tight true position tolerances across the entire housing.
4Device complexity
If side walls are used to align ferrule holders, then alignment structure is simple, but alignment precision in X and Y directions is insufficient
Solution Approach 1:
The invention uses asymmetric projections on the ferrule holder that have different dimensions in different directions. The projections are designed with specific width and height relationships that provide differential constraint: the width controls X-direction alignment while the height controls Y-direction alignment. This asymmetric geometry enables precise alignment in both directions without requiring complex multi-feature alignment structures.
Data Source
AI summary
An adapter with novel alignment features engages alignment features on a plug, providing general alignment of the ferrule holders and ferrules in the plug. After the plug engages the adapter, the ferrule holders engage a second set of alignment features in the adapter to provide fine alignment for the ferrules.