Non-Circular Multicore Fiber Alignment via Asymmetric Drawing
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Solution Overview
Problem
The alignment of individual cores in multicore fibers with circular cross-sections poses challenges in connecting devices due to the difficulty in aligning the cores with signal paths, limiting the efficiency of space division multiplexing and signal carrying capacity.
Innovation Solution
A method of forming multicore fibers with non-circular cross-sectional shapes, such as rectangular or square shapes, having sharp corners and flat surfaces, which allows for accurate alignment with connecting devices by maintaining the shape during the drawing process using a preform with a non-circular cross-section and a draw furnace with a circular inside diameter ratio greater than 0.60.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a circular cross-section multicore fiber is used, then the fiber can be easily manufactured using conventional draw furnaces, but the alignment of individual cores with connecting devices becomes difficult
Solution Approach 1:
The patent applies asymmetry by changing the fiber cross-section from a circular shape to a non-circular shape (such as rectangular or triangular). This asymmetric geometry provides distinct reference features that enable precise alignment with connecting devices, directly resolving the alignment precision problem while maintaining manufacturability through the preform-based drawing process
2Shape
If a non-circular cross-section preform is drawn with a large ratio to furnace diameter, then the non-circular shape and corners are maintained during drawing, but the preform size must be carefully controlled
Solution Approach 1:
The patent applies parameter changes by optimizing the ratio of the preform's maximum dimension to the draw furnace inside diameter to be greater than 0.60. This specific parameter range ensures that the non-circular cross-sectional shape and corners are maintained during the drawing process, preventing excessive rounding while enabling successful fiber formation
Solution Approach 2:
The patent applies preliminary action by pre-forming the non-circular cross-section with defined corners in the preform structure before the drawing process. This preliminary shaping ensures that the desired geometric features are already in place and can be maintained during drawing, rather than attempting to create them during the forming process
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 non-circular cross-sectional shape enables easy and reliable alignment and connection of the multicore fibers, enhancing signal carrying capacity and multiplexing capabilities by maintaining the shape and sharpness of corners during the drawing process.
Implementation Method 1
inserting the preform in a draw furnace having a substantially circular cross section
Implementation Method 2
drawing a multicore fiber from the preform to achieve a reduction in cross-sectional size as the fiber is drawn
Data Source
AI summary
A multicore fiber is provided. The multicore fiber includes a plurality of cores spaced apart from one another, and a cladding surrounding the plurality of cores and defining a substantially rectangular or cross-sectional shape having four corners. Each corner has a radius of curvature of less than 1000 microns. The multicore fiber may be drawn from a preform in a circular draw furnace in which a ratio of a maximum cross-sectional dimension of the preform to an inside diameter of the preform to an inside diameter of the draw furnace is greater than 0.60. The multicore fiber may have maxima reference surface.