Optical Connector Adhesive Refractive Index Matching
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Solution Overview
Problem
Conventional optical connectors require a refractive-index matching plate, which complicates installation and increases costs due to the need for precise alignment and surface smoothing to reduce optical coupling losses.
Innovation Solution
An optical connector design using an adhesive with a refractive index between that of the optical fiber core wire and the lens member, which reduces scattering and Fresnel losses by filling the gap between the end faces, eliminating the need for a separate refractive-index matching plate and simplifying installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a refractive-index matching plate is used to reduce optical coupling loss, then optical coupling loss is reduced, but device complexity and installation difficulty increase
Solution Approach 1:
The patent merges the refractive-index matching plate function directly into the lens member by forming a refractive-index matching layer on the lens surface. This integration eliminates the need for a separate matching plate component, reducing device complexity while maintaining the optical coupling loss reduction benefit. The matching layer is formed as an integral part of the lens member through coating or deposition processes.
Solution Approach 2:
The patent extracts the refractive-index matching function from the separate matching plate and transfers it to the lens member surface. By taking out this specific function and applying it directly to the lens, the system eliminates the need for the separate matching plate component, simplifying the overall device structure and installation process while preserving the optical performance improvement.
2Loss of energy
If a refractive-index matching plate is used to reduce scattering loss, then scattering loss is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent combines the scattering loss reduction function with the lens member by forming a refractive-index matching layer on its surface. This integration allows the scattering loss reduction benefit to be achieved without requiring separate precision processing of a matching plate, as the layer is applied directly to the lens surface during or after lens fabrication.
Solution Approach 2:
The patent changes the refractive index parameter of the lens member surface by applying a matching layer with refractive index intermediate between the optical fiber core and the lens material. This parameter change reduces the refractive index difference at the interface, thereby reducing scattering loss without requiring extreme surface smoothness, as the gradient index transition mitigates the scattering effect.
3Loss of energy
If a refractive-index matching plate is used to reduce Fresnel loss, then Fresnel loss is reduced, but device complexity increases
Solution Approach 1:
The patent merges the Fresnel loss reduction function into the lens member by forming a refractive-index matching layer on its surface. This integration eliminates the need for a separate matching plate component, reducing the total number of parts and simplifying the device structure, while maintaining the Fresnel loss reduction benefit through the intermediate refractive index layer.
Solution Approach 2:
The patent makes the lens member multi-functional by adding the refractive-index matching layer, which simultaneously serves as both the optical focusing element and the refractive-index matching interface. This universal design allows the lens member to perform both its primary optical function and the Fresnel loss reduction function, eliminating the need for a separate matching plate and reducing device complexity.
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 adhesive effectively reduces optical coupling losses, simplifies the installation process, and lowers costs by acting as a substitute for the refractive-index matching plate, ensuring high optical transmittance and alignment precision.
Implementation Method 1
the adhesive 10 has a refractive index N, which is between a refractive index N1 of the lens ferrule 8 and a refractive index N2 of the optical fiber core wire 3a
Implementation Method 2
the Fresnel loss (Fresnel reflection loss) can be reduced as compared with a case in which air is present between the end face of the optical fiber core wire 113 and the end face of the lens array 112
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
The optical connector includes an inner ferrule 7 having a fiber core-wire insertion hole 73, into which an optical fiber core wire 3a of an optical fiber 3 is inserted, with a front end face of the optical fiber core wire 3a inserted into the fiber core-wire insertion hole 73 being exposed, and a lens ferrule 8 having a lens unit 82 arranged on an axis of the optical fiber core wire 3a and made of a light transmitting material. An adhesive 10 having a refractive index N, which is between a refractive index N1 of the lens ferrule 8 and a refractive index N2 of the optical fiber core wire 3a, and having optical transparency is filled between a front end face of the optical fiber core wire 3a and an end face of the lens ferrule 8 opposite thereto.