Multi-Core Fiber Junction with Slanted End Faces
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Solution Overview
Problem
Conventional technologies face challenges in reducing reflection during interconnections of multi-core optical fibers, as the cores are not centered at the end faces, making it difficult to apply physical contact coupling effectively.
Innovation Solution
A multi-core optical fiber interconnection structure is developed with slanted end faces for each fiber, aligned to minimize core connection losses, using markers to specify core positions and ferrules for precise alignment, achieving optical return loss of at least 30 dB and connection losses of no more than 0.4 dB.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If PC coupling with convex-shaped end faces is used for single-core optical fibers, then reflection at the interconnection is reduced, but this method cannot be applied to multi-core optical fibers because the cores are not located at the center of the end face
Solution Approach 1:
The invention applies different end face configurations to different regions: the central region has a convex shape for reflection reduction, while the peripheral region contains the off-center core. This local differentiation allows the end face to simultaneously achieve low reflection properties and proper core alignment for multi-core fibers.
Solution Approach 2:
The end face is designed with an asymmetric structure where the convex region and the core position are not coincident. The core is intentionally positioned at an off-center location while the convex shape remains centered, creating an asymmetric configuration that accommodates multi-core fiber requirements while maintaining reflection reduction capabilities.
2Ease of manufacture
If conventional polishing methods are used for multi-core optical fibers, then manufacturing is simple, but core position alignment and connection precision deteriorate due to the inability to apply PC coupling
Solution Approach 1:
The core positions are predetermined and marked on the end face before the polishing process. This preliminary marking guides the polishing operation to create convex shapes at the correct locations, ensuring that the final polished end face achieves both the desired shape and proper core alignment without requiring complex post-processing adjustments.
3Ease of operation
If the end faces of multi-core optical fibers are connected without specific alignment features, then the connection process is simple, but core pitch variation and connection loss increase
Solution Approach 1:
Visual markers or indicators are incorporated on the end faces to provide visual feedback during the connection process. These markers change appearance or position based on alignment status, allowing operators to quickly identify when cores are properly aligned, thereby maintaining operational simplicity while ensuring connection reliability through reduced core pitch variation.
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 structure effectively reduces reflection at interconnections between multi-core optical fibers by minimizing core pitch variations and ensuring low back reflection, enabling low-loss coupling.
Implementation Method 1
capable of reducing reflection at an interconnection where respective end faces of first and second multi-core optical fibers are connected to each other
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3A~3B
AI summary
A multi-core optical fiber interconnection structure has a first multi-core optical fiber with a slanted end face and a second multi-core optical fiber with a slanted end face. In a state in which the slanted end faces face each other, each of cores of the first multi-core optical fiber is optically coupled to a corresponding one of cores of the second multi-core optical fiber in a one-to-one correspondence relation. The facing condition between the slanted end faces is adjusted so as to minimize variation in core pitches of pairs of the cores each in the one-to-one correspondence relation.