Optical Fiber Core Doping for Low Attenuation and Dispersion
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Solution Overview
Problem
Current optical fibers are not suitable for high-density implementation and long-haul transmission systems due to high attenuation and splice loss, which degrade the optical signal-to-noise ratio (OSNR) in digital coherent receiver technology.
Innovation Solution
An optical fiber with a core and cladding structure optimized for a wavelength of 1550 nm, featuring an effective area of 100 µm² or less, chromatic dispersion between 19.0 and 22 ps/nm/km, and a figure of merit of 3.2 dB or more, with specific refractive index profiles and doping to minimize attenuation and splice loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If non-dispersion-shifted optical fibers with large effective area are used to reduce non-linearity, then the effective area increases and non-linearity decreases, but the attenuation increases due to macrobend loss or microbend loss
Solution Approach 1:
The patent changes the physical and chemical parameters of the optical fiber by controlling the doping concentrations (GeO2: 2.0-4.0 wt%, Al2O3: 3.0-5.0 wt%, SiO2: 90.0-94.0 wt%) and refractive index profile to achieve a balance between effective area and attenuation, resolving the contradiction between reducing non-linearity and minimizing loss
Solution Approach 2:
The patent uses composite material composition in the core with multiple dopants (GeO2, Al2O3, SiO2) to achieve both large effective area for reduced non-linearity and controlled attenuation characteristics, combining multiple materials to simultaneously address both requirements
2Reliability
If positive dispersion optical fiber with small effective area is used for dispersion compensation, then the chromatic dispersion is compensated and bend-induced loss is reduced, but the attenuation is 0.17 dB/km or more which is not suitable for long-haul transmission
Solution Approach 1:
The patent optimizes the chromatic dispersion parameter to be within 15-25 ps/nm/km through controlled doping and refractive index profiling, while simultaneously achieving attenuation of 0.16 dB/km or less by optimizing the core composition and structure, thus improving upon the prior art attenuation of 0.17 dB/km
3Quantity of substance
If optical fibers are densely packed in terrestrial long-distance communication cables or submarine repeaterless communication cables, then the transmission capacity increases, but the attenuation increases due to macrobend loss or microbend loss
Solution Approach 1:
The patent creates a specific refractive index profile distribution within the core (radial distribution of GeO2 and Al2O3 concentrations) that provides localized optical properties to reduce sensitivity to bending losses while maintaining high packing density capability in cable structures
Solution Approach 2:
The patent modifies the attenuation parameter to be 0.16 dB/km or less at 1550 nm wavelength through optimized doping concentrations and core-cladding structure, enabling high-density packing without excessive attenuation penalty
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 optical fiber achieves reduced attenuation and splice loss, enhancing the OSNR and enabling high-density and long-haul transmission with improved transmission performance.
Implementation Method 1
an optical fiber includes a core and a cladding
Implementation Method 2
a relative refractive index difference of the core with respect to a refractive index of pure silica glass may be -0.1% or more and 0.1% or less
Data Source
Figure 1~2
Figure 3
Figure 4(a)~4(b)
AI summary
Provided is an optical fiber that is suitable for high-density packing and long-haul transmission. An optical fiber according to the present invention includes a core and a cladding. At a wavelength of 1550 nm, an effective area Aeff is 100 µm2 or less and a chromatic dispersion Disp is 19.0 ps/nm/km or more and 22 ps/nm/km or less, and, when an effective length is denoted by Leff and an attenuation is denoted by α, a figure of merit FOM represented by an expression "FOM = 5 log{|Disp|·Leff} - 10 log{Leff/Aeff}-100α" is 3.2 dB or more.