Dual-Layer Optical Fiber Coating for Thin-Fiber Pressure Resistance
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Solution Overview
Problem
Reducing the diameter of optical fibers while maintaining lateral pressure resistance and low-temperature characteristics is challenging, as thinner coating layers increase transmission loss due to micro-bending and deteriorate resistance characteristics.
Innovation Solution
The optical fiber design includes a glass fiber with a core and cladding, coated by a primary resin layer with a thickness of 5 μm or more and an elastic modulus of 0.1 to 0.4 MPa, and a secondary resin layer with a thickness of 5 μm or more and an elastic modulus of 1200 to 2800 MPa, along with controlled eccentricity to prevent breakage and maintain structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the coating resin layer thickness is reduced to decrease fiber outer diameter, then the fiber diameter is reduced, but lateral pressure resistance deteriorates and transmission loss increases due to micro-bending
Solution Approach 1:
The coating resin layer is divided into two distinct layers: a primary resin layer (5-20 μm) with low elastic modulus (0.1-0.4 MPa) that provides lateral pressure resistance and micro-bending suppression, and a secondary resin layer (5-30 μm) with high elastic modulus (1200-2800 MPa) that provides mechanical strength. This segmentation allows each layer to perform its specific function optimally while maintaining a reduced total outer diameter of 120-170 μm.
Solution Approach 2:
Different regions of the coating structure are assigned different material properties: the inner primary resin layer has soft, compliant characteristics to cushion against lateral pressure and prevent micro-bending, while the outer secondary resin layer has rigid, strong characteristics to provide overall structural support. This local differentiation of material qualities resolves the contradiction between thin coating and adequate protection.
2Length of stationary object
If the coating resin layer thickness is reduced to decrease fiber outer diameter, then the fiber diameter is reduced, but transmission loss increases due to micro-bending
Solution Approach 1:
The segmented coating structure with a primary resin layer specifically designed to suppress micro-bending through its low elastic modulus and appropriate thickness (5-20 μm) prevents energy loss from micro-bending, while the total coating thickness is optimized to maintain a reduced outer diameter of 120-170 μm.
Solution Approach 2:
The primary resin layer's soft, compliant local quality provides micro-bending suppression to minimize transmission loss, while the overall reduced coating thickness maintains a compact fiber diameter suitable for high-density applications.
3Length of stationary object
If the glass fiber outer diameter is reduced to 99-101 μm, then the fiber becomes more compact, but structural integrity and resistance to breakage may deteriorate
Solution Approach 1:
The secondary resin layer's rigid, high-strength local quality (elastic modulus 1200-2800 MPa) compensates for the reduced glass fiber diameter by providing external mechanical support and protection against breakage, allowing the glass fiber to maintain a compact 99-101 μm diameter while the overall fiber structure retains adequate strength through the protective coating layers.
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 allows for a reduced fiber diameter with improved lateral pressure resistance and low-temperature characteristics, minimizing transmission loss and breakage frequency, while maintaining compatibility with existing tools and instruments.
Implementation Method 1
The primary resin layer has an in situ elastic modulus of from 0.1 MPa to 0.4 MPa
Implementation Method 2
The secondary resin layer has an in situ elastic modulus of from 1200 MPa to 2800 MPa
Implementation Method 3
A maximum value of amplitude of an amount of eccentricity is 6 μm or less in a spectrum obtained by measuring, at a plurality of measurement points set at predetermined intervals in an axial direction of the glass fiber, the amount of eccentricity of the glass fiber from a central axis relative to the outer periphery of the secondary resin layer
Data Source
AI summary
The optical fiber includes a glass fiber and a coating resin layer. The coating resin layer includes a primary resin layer and a secondary resin layer. The glass fiber has an outer diameter of from 99 μm to 101 μm. The secondary resin layer has an outer diameter of from 120 μm to 170 μm. The primary resin layer has an in situ elastic modulus of from 0.1 MPa to 0.4 MPa. The secondary resin layer has an in situ elastic modulus of from 1200 MPa to 2800 MPa. A maximum value of amplitude of an amount of eccentricity is 6 μm or less in a spectrum obtained by measuring the amount of eccentricity of the glass fiber and by applying Fourier transform to a waveform representing the amount of eccentricity.