Inclined Axis Ferrule Reducing Return Light
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Solution Overview
Problem
Ferrules used in optical components can suffer from reflected return light at the boundary face between the ferrule and air, which can interfere with optical output, particularly when the optical axes of the ferrules and lenses coincide, leading to light being concentrated back into the optical fibers.
Innovation Solution
The ferrule design incorporates an inclined second optical axis relative to the first optical axis, with guide portions and lenses arranged asymmetrically to reduce reflection, allowing for stable and reliable connection even when the second optical axis is inclined, thereby minimizing reflected return light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the optical axes of the ferrules and lenses coincide, then the optical connection efficiency is improved, but the reflected return light increases
Solution Approach 1:
The patent applies asymmetry by inclining the second optical axis relative to the first optical axis. The lens is positioned such that its optical axis is inclined at an angle θ (0 < θ < 45 degrees) relative to the optical axis of the optical waveguide member. This asymmetric arrangement causes reflected light to diverge away from the optical fiber core, reducing return loss while maintaining effective optical coupling through the inclined second optical axis between opposing ferrules.
Solution Approach 2:
The patent introduces a dimensional change by tilting the optical axis in a angular dimension rather than maintaining strict axial alignment. The second optical axis is inclined relative to the first optical axis, creating a three-dimensional optical path that separates the reflection direction from the incident light path, thereby reducing reflected return light while preserving optical connection efficiency.
2Object-generated harmful factors
If the second optical axis is inclined relative to the first optical axis, then the reflected return light is reduced, but the alignment precision requirement increases
Solution Approach 1:
The patent incorporates guide portions (guide pins and guide holes) that preliminarily establish the relative position and orientation of opposing ferrules before final optical coupling. These guide portions constrain the ferrules to a predetermined spatial relationship, pre-aligning the inclined optical axes and reducing the precision burden on final assembly operations.
Solution Approach 2:
The guide portions act as intermediary elements that mediate the alignment between opposing ferrules. By providing mechanical guidance through pins and holes with predetermined geometry, the system translates the complex requirement of inclined optical axis alignment into simpler mechanical constraint operations, making high-precision alignment achievable through sequential assembly steps.
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 design effectively reduces reflected return light, enabling more efficient optical connections by ensuring that the ferrules can be connected with coinciding center axes while maintaining a stable and reliable fitting structure, even when the optical axes are inclined.
Implementation Method 1
a second optical axis L2 between the light incidence/emission plane 18b and the ferrule on the other side is inclined relative to a first optical axis L1 provided by a holding hole 16
Data Source
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AI summary
A ferrule 10 includes a plurality of holding holes 16, a light incidence/emission plane 21 to pass light entering or emitted from optical fibers F2 respectively held at the plurality of holding holes 16, a plurality of lenses 31 disposed on an optical axes between the respective plural holding holes 16 and the light incidence/emission plane 21, and two or more guide portions to determine a relative position with a ferrule 10 on the other side. A second optical axis L2 between the light incidence/emission plane 21 and the ferrule 10 on the other side is inclined relative to a Z direction. A positional relation between the two or more guide portions is 180-degree rotationally symmetric around a reference axial line extending in the Z direction. A plurality of lenses 31 is disposed disproportionately in a direction opposite to an inclination direction of the second optical axis L2 from a position line-symmetric relative to a straight line crossing with the reference axial line and parallel to an X direction.