Optical Fiber Core Phosphorus Radius Ratio
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Solution Overview
Problem
Conventional optical fibers face challenges in reducing transmission loss due to glass structure non-uniformity and infrared absorption, particularly at a wavelength of 1550 nm, where the balance of phosphorus concentration and glass structure defects affects the refractive index profile and viscosity.
Innovation Solution
An optical fiber comprising silica-based glass with a core containing phosphorus, chlorine, and fluorine, along with an alkali metal or alkaline earth metal element, featuring a phosphorus-containing region with a specific radius ratio (Rp/Ra) of 0.3 or more, optimized to reduce transmission loss by balancing glass structure non-uniformity and viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the core contains phosphorus to reduce glass structure non-uniformity, then transmission loss is reduced, but infrared absorption increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the phosphorus concentration in the core to be 0.01-5 mass% and the phosphorus-containing region radius ratio Rp/Ra to be 0.05-2.0. This optimization balances the beneficial effect of reduced glass structure non-uniformity against the harmful infrared absorption, achieving minimum transmission loss at 1550 nm wavelength.
Solution Approach 2:
The patent uses composite materials by combining phosphorus with other dopants (chlorine, fluorine, alkali metals, or alkaline earth metals) in the core. This composite doping approach allows simultaneous control of multiple parameters including refractive index, viscosity, and glass structure uniformity while managing infrared absorption effects.
2Loss of energy
If the core contains chlorine or fluorine to reduce viscosity, then glass rearrangement is promoted and transmission loss is reduced, but refractive index control becomes more difficult
Solution Approach 1:
The patent employs composite materials by combining chlorine, fluorine, phosphorus, and alkali metals/alkaline earth metals in the core. This multi-element composition allows the refractive index to be controlled through the synergistic effects of different dopants while maintaining low viscosity and reduced transmission loss.
Solution Approach 2:
The patent applies parameter changes by controlling the concentration ranges of multiple elements: phosphorus (0.01-5 mass%), chlorine and fluorine (0.001-1 mass% each), and alkali metals/alkaline earth metals (0.0001-0.01 mass% each). This multi-parameter optimization enables precise control of refractive index while achieving low transmission loss.
3Loss of energy
If the phosphorus-containing region radius Rp/Ra is increased to reduce glass structure non-uniformity, then transmission loss is reduced, but the core-cladding interface uniformity is compromised
Solution Approach 1:
The patent applies parameter changes by optimizing the phosphorus-containing region radius ratio Rp/Ra to be within 0.05-2.0. This specific range allows sufficient phosphorus distribution to reduce glass structure non-uniformity while maintaining core-cladding interface uniformity, achieving minimum transmission loss without compromising structural stability.
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 transmission loss to 0.148 dB/km or less at 1550 nm by optimizing the phosphorus-containing region's radius and concentration, minimizing glass structure non-uniformity and infrared absorption, while maintaining sufficient refractive index differences between the core and cladding.
Implementation Method 1
the viscosity of the core of the optical fiber obtained by drawing the optical fiber preform is reduced. As the viscosity of the core is reduced, the rearrangement of the glass in the core is promoted, and the transmission loss of the manufactured optical fiber due to the ray scattering is reduced
Implementation Method 2
the viscosity of the core of the optical fiber obtained by drawing the optical fiber preform is reduced
Implementation Method 3
The cladding has a refractive index lower than a refractive index of the core
Implementation Method 4
defects in the glass structure represented by D2 line intensity are reduced if silica glass contains an appropriate amount of phosphorus, and the reduction of defects in the glass structure reduces transmission loss
Implementation Method 5
the transmission loss is increased due to the infrared absorption of phosphor oxide if the silica glass contains a large amount of phosphorus
Data Source
AI summary
One embodiment of the present disclosure relates to an optical fiber having lower transmission loss. The optical fiber is an optical fiber comprised of silica-based glass and includes a core including a central axis and a cladding. The cladding surrounds the core and has a refractive index lower than a refractive index of the core. The core contains phosphorus, chlorine, and fluorine. The core further includes an alkali metal element or an alkaline earth metal element. In a cross section of the optical fiber orthogonal to the central axis, a ratio Rp/Ra of a radius Rp of a phosphorus-containing region with respect to a radius Ra of the core is 0.3 or more.