Dual-Layer Optical Fiber Coating for Micro-Bending Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Reducing the diameter of optical fibers while maintaining the glass fiber diameter leads to thinner coating resin layers, increasing transmission loss due to micro-bending and deteriorating lateral pressure resistance characteristics, and low-temperature characteristics.
Innovation Solution
A glass fiber with a core and cladding, coated by a primary resin layer and a secondary resin layer, where the primary resin layer has a thickness of 5 μm or more and an elastic modulus of 0.1 MPa to 0.5 MPa, and the secondary resin layer has a thickness of 5 μm or more and an elastic modulus of 1200 MPa to 2800 MPa, with a maximum eccentricity amplitude of 6 μm or less, to maintain structural integrity and resistance to pressure and temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the glass fiber diameter is reduced to 125 μm or less, then the outer diameter of the optical fiber is reduced, but the coating resin layer becomes thinner causing increased transmission loss due to micro-bending and deteriorated lateral pressure resistance characteristics
Solution Approach 1:
The coating resin layer is divided into two distinct layers: a primary resin layer (5-20 μm) with low elastic modulus (0.1-0.5 MPa) that provides buffering against micro-bending, and a secondary resin layer (5-50 μm) with high elastic modulus (1200-2800 MPa) that provides lateral pressure resistance. This segmentation allows each layer to perform its specific function optimally, resolving the contradiction between thin coating and adequate protection.
Solution Approach 2:
The patent uses a composite structure combining two resin materials with vastly different elastic moduli. The primary resin layer uses a soft, compliant material to absorb micro-bending stresses, while the secondary resin layer uses a rigid material to resist lateral pressure. This composite approach enables the coating to simultaneously protect against both micro-bending and lateral pressure, maintaining reliability even with reduced overall diameter.
2Volume of moving object
If the coating resin layer is made thinner to reduce fiber diameter, then the outer diameter is reduced, but low-temperature characteristics deteriorate
Solution Approach 1:
The segmented coating structure addresses low-temperature characteristics by assigning different thermal protection functions to each layer. The primary resin layer's low elastic modulus allows it to remain flexible at low temperatures, preventing brittleness and maintaining protection against micro-bending in cold environments, while the secondary layer provides structural integrity.
Solution Approach 2:
By controlling the elastic modulus parameter of the primary resin layer to be very low (0.1-0.5 MPa), the material maintains its viscoelastic properties across a wide temperature range including low temperatures. This parameter optimization ensures the coating remains effective for temperature compensation without requiring excessive thickness.
3Strength
If the primary resin layer elastic modulus is reduced to improve lateral pressure resistance, then lateral pressure resistance characteristics improve, but the layer becomes more compliant and may increase micro-bending
Solution Approach 1:
The segmentation of the coating into two layers with different elastic moduli resolves this contradiction by separating the functions: the primary resin layer (0.1-0.5 MPa) is optimized for micro-bending protection through high compliance, while the secondary resin layer (1200-2800 MPa) is optimized for lateral pressure resistance through rigidity. Together, they achieve both protection goals simultaneously.
Solution Approach 2:
Each layer is designed with local quality optimized for its specific function. The primary resin layer has locally optimized low elastic modulus properties specifically at the glass fiber interface where micro-bending occurs, while the secondary resin layer has locally optimized high elastic modulus properties for lateral pressure resistance at the outer coating surface.
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 124 μm to 126 μm. The secondary resin layer has an outer diameter of from 145 μm to 170 μm. The primary resin layer has an in situ elastic modulus of from 0.1 MPa to 0.5 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.