Ge-Free Core Optical Fiber for Non-Linear Effect Reduction
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Solution Overview
Problem
High power optical fiber systems suffer from non-linear optical effects and attenuation issues due to large effective area fibers, which lead to signal degradation and increased macrobending losses over long distances.
Innovation Solution
An optical waveguide fiber with a Ge-free core and specific refractive index profiles, including a central core region, a fluorine-doped annular region, and a cladding, optimized to provide an effective area of 90 μm2 to 160 μm2 and attenuation less than 0.175 dB/km at 1550 nm, minimizing non-linear effects and macrobend-induced losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the effective area of an optical fiber is increased to reduce non-linear optical effects, then signal degradation from non-linear effects is reduced, but macrobending induced losses increase
Solution Approach 1:
The patent applies parameter changes by precisely controlling the refractive index profile parameters (Δ0MAX, Δ1(r=2.5 μm), Δ2MIN) and the radial extent (r1, r2) of different core regions. This optimization allows the fiber to achieve large effective area (90-160 μm²) while maintaining low macrobending losses through the specific parameter combination of a Ge-free core with fluorine doping and controlled refractive index gradients.
Solution Approach 2:
The patent uses composite material principles by creating a multi-region core structure with different compositions: a Ge-free central core region, a Ge-free first annular core region with specific refractive index, and a fluorine-doped second annular region. This composite structure enables simultaneous achievement of large effective area and low bending losses by combining materials with different optical properties in specific spatial arrangements.
2Object-affected harmful factors
If the effective area of an optical fiber is increased to reduce non-linear optical effects, then signal quality is improved, but attenuation increases
Solution Approach 1:
The patent achieves low attenuation (<0.175 dB/km) in large effective area fibers by optimizing parameters including the Ge-free composition, fluorine doping concentration in the second annular region, and the specific refractive index profile parameters (Δ0MAX, Δ1(r=2.5 μm), Δ2MIN). These parameter optimizations minimize both intrinsic material absorption and scattering losses while maintaining large effective area.
Solution Approach 2:
The patent applies local quality by creating spatially varying refractive index profiles in different core regions. The Ge-free central region provides low loss transmission, the first annular region with specific Δ1(r=2.5 μm) controls mode distribution, and the fluorine-doped second annular region with negative Δ2(r) provides confinement. This local optimization of material properties at different radial positions enables simultaneous large effective area and low attenuation.
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 solution effectively reduces signal degradation and macrobend-induced losses while maintaining a large effective area, enabling reliable high-power optical transmission with low attenuation over long distances.
Implementation Method 1
an optical waveguide fiber having a large effective area (Aeff) reduces non-linear optical effects
Implementation Method 2
a central core region extending radially outwardly from a centerline to a radius r0, and having a relative refractive index percent profile Δ0(r) in % measured relative to pure silica
Data Source
AI summary
According to some embodiments an optical waveguide fiber comprises:(i) a Ge free core having an effective area of 90 μm2 to 160 μm2, at a 1550 nm wavelength, and α value 12≦α≦25, said core comprising:(a) a central core region extending radially outwardly from a centerline to a radius 0 μm≦r0≦2 μm, and having a relative refractive index percent profile Δ0(r) in % measured relative to pure silica, wherein −0.1%≦Δ0(r)≦0.1%, wherein the central core region has a maximum relative refractive index percent, Δ0MAX;(b) a first annular core region surrounding and directly adjacent to the central core region and extending to an outer radius r1, wherein 4.8 μm≦r1≦10 μm, and having a relative refractive index percent profile, Δ1(r) in % measured relative to pure silica, and a minimum relative refractive index, Δ2MIN, and the relative refractive index measured at a radius r=2.5 μm being:−0.15≦Δ1(r=2.5 μm)≦0, and Δ0MAX≧Δ1(r=2.5 μm);(c) a fluorine doped second annular region surrounding and directly adjacent to the first annular core region and extending to a radius 13 μm≦r2≦30 μm and having a negative relative refractive index percent profile, Δ2(r) in %, measured relative to pure silica,with a minimum relative refractive index percent Δ2MIN being:Δ2MIN≦Δ1(r=2.5 μm), and −0.7%≦Δ2MIN≦−0.28%;(ii) a cladding surrounding the core and having a relative refractive index percent Δc(r) in % measured relative to pure silica, and Δc(r)=Δ2MIN±0.3%;wherein the relative refractive index profile of the optical fiber is selected to provide attenuation of no more than 0.175 dB/km at the wavelength of 1550 nm.