Passive Alignment System Using Meltable Elements for Optical Modules
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Solution Overview
Problem
Active alignment techniques for optical communications modules are costly, time-consuming, and difficult to perform in the field, especially for aligning multi-mode optical fibers with photodiodes due to the decreasing aperture size of photodiodes, making it challenging to achieve precise passive alignment without using a vision system or precision alignment stage.
Innovation Solution
A passive alignment system using meltable elements and standoff devices that transition from pre-molten to molten states at specific temperatures to precisely align optical fibers with optoelectronic elements in three dimensions, allowing for precise alignment of optical waveguides and fibers with light sources or light detectors without activating the optoelectronic elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If passive alignment techniques are used to align multi-mode fibers with photodiodes, then alignment cost and time are reduced, but alignment precision deteriorates due to decreasing photodiode aperture size
Solution Approach 1:
The patent introduces alignment marks as intermediary features that mediate between the photodiode and fiber positioning. These marks serve as reference points that enable passive alignment systems to achieve precise alignment without requiring complex active alignment equipment, thus resolving the contradiction between reduced alignment time and maintained alignment precision.
Solution Approach 2:
The patent changes the parameter of alignment reference from direct optical signal detection to physical mark-based positioning. By transitioning from active optical alignment to passive mark-based alignment, the system achieves both time efficiency and precision for multi-mode fiber connections.
2Manufacturing precision
If active alignment techniques are used with vision systems and precision alignment stages, then alignment precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses alignment marks as intermediary reference features that eliminate the need for complex vision systems and precision alignment stages. These marks provide a simple yet effective reference system that maintains alignment precision while dramatically reducing device complexity and cost.
Solution Approach 2:
The alignment marks function as simple, inexpensive reference features that replace expensive active alignment equipment. The marks are integrated into the package structure and provide sufficient alignment precision without requiring costly vision systems or precision stages.
3Speed
If photodiode aperture size is reduced for higher speed operation, then operational speed is improved, but alignment difficulty increases for passive alignment systems
Solution Approach 1:
The alignment marks serve as intermediary reference features that decouple the alignment process from the photodiode aperture size. By providing external reference points, the marks enable passive alignment systems to accurately position fibers even when photodiode apertures are reduced for higher speed operation.
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
Enables precise passive alignment of multiple optical fibers or waveguides with sub-micron accuracy to respective optical axes of light sources or light detectors, reducing costs and complexity compared to active alignment methods, and accommodating the alignment of both single-mode and multi-mode fibers with smaller photodiode apertures.
Implementation Method 1
one or more first meltable elements disposed on a first surface, one or more second meltable elements disposed on the first surface or on a second surface... The first and second meltable elements transition from first and second pre-molten states, respectively, to first and second molten states, respectively, when subjected to first and second temperatures, respectively
Data Source
AI summary
A passive alignment system is provided that comprises one or more first meltable elements disposed on a surface, one or more second meltable elements disposed on a surface and one or more first standoff devices. The first and second meltable elements transition from first and second pre-molten states, respectively, to first and second molten states, respectively, when subjected to first and second temperatures, respectively. In the first molten state, the first meltable elements control relative alignment between the surfaces in first and second dimensions. In the second molten state, the second meltable elements and the first standoff devices control relative alignment between the surfaces in a third dimension. The passive alignment system is suitable for use in a parallel optical communications module to precisely passively align ends of a plurality of optical fibers or waveguides with respective light sources or light detectors of the module.