Ferrule Inner Diameter Control for Optical Connector Alignment
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Solution Overview
Problem
Manufacturing variations can cause gaps between optical fibers and ferrule holes, leading to positional deviations in optical connectors, as existing methods often result in an inner diameter equal to the outer diameter of the fiber, making it difficult to insert the fiber and maintain accurate alignment.
Innovation Solution
A ferrule with a fiber hole inner diameter smaller than the optical fiber's outer diameter, made from materials with a specific coefficient of linear expansion (1.7×10−5 to 3.0×10−5), allowing the inner diameter to expand and accommodate the fiber when heated, ensuring accurate alignment and fixing the fiber through thermal shrinkage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the inner diameter of the fiber hole is made equal to the outer diameter of the optical fiber, then the optical fiber can be easily inserted, but manufacturing variations cause gaps between the fiber hole and optical fiber leading to positional deviation
Solution Approach 1:
The patent applies parameter changes by modifying the inner diameter of the fiber hole to be smaller than the outer diameter of the optical fiber (specifically 0.004mm to 0.020mm smaller). This parameter adjustment ensures that the optical fiber is tightly fitted within the fiber hole, eliminating gaps caused by manufacturing variations and preventing positional deviation, while still allowing for reliable insertion and fixation.
2Manufacturing precision
If the inner diameter of the fiber hole is made smaller than the outer diameter of the optical fiber to suppress positional deviation, then alignment accuracy improves, but the optical fiber cannot be inserted through the fiber hole
Solution Approach 1:
The patent resolves this contradiction by precisely controlling the inner diameter parameter of the fiber hole to be slightly smaller than the optical fiber outer diameter (0.004mm to 0.020mm smaller). This optimized parameter enables both tight fitting for high alignment accuracy and successful insertion, as the small difference allows the fiber to be inserted while maintaining close contact to prevent positional deviation.
3Ease of operation
If heating is applied to expand the fiber hole for insertion, then the optical fiber can be inserted, but the material must have specific thermal expansion properties to maintain precision after cooling
Solution Approach 1:
The patent applies thermal expansion by heating the ferrule to expand the fiber hole, allowing the optical fiber to be inserted. The material is selected with a coefficient of linear expansion of 1.7×10−5 to 3.0×10−5 to ensure that after cooling, the fiber hole contracts to tightly fit the optical fiber, maintaining high alignment accuracy without positional deviation.
Solution Approach 2:
The patent changes the physical state parameter of the ferrule material through heating and cooling cycles. During heating, the inner diameter of the fiber hole increases to allow insertion; during cooling, it contracts to achieve tight fitting. This parameter change enables both easy insertion and high precision alignment.
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
This solution reliably suppresses positional deviations and ensures high accuracy in matching the central axes of the fiber hole and optical fiber, allowing for precise insertion and assembly of optical connectors.
Implementation Method 1
the material of the main body part has a coefficient of linear expansion within a range of 1.7×10−5 to 3.0×10−5... it is possible to make the inner diameter of the fiber hole larger than the outer diameter of the cladding by heating to a predetermined temperature
Implementation Method 2
a cooling step of fixing the optical fiber in the fiber hole by cooling the main body part
Data Source
AI summary
A ferrule, for an optical connector, includes: a main body part formed with a fiber hole configured to accommodate insertion of an optical fiber. The main body part is formed of a material having a coefficient of linear expansion within a range of 1.7×10−5 to 3.0×10−5. A ratio of an inner diameter dh of the fiber hole to an outer diameter df of a cladding of the optical fiber is within a range of 99.632 [%]≤dh/df≤99.880 [%].