Radiation-Resistant Laser Optical Fiber Preform Core Rod
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Solution Overview
Problem
Existing optical fibers face significant radiation-induced loss and decreased laser slope efficiency due to ionization radiation in space applications, particularly in rare earth-doped silica fibers, where current solutions inadequately address the pre-treatment process and result in increased background loss and reduced mechanical strength.
Innovation Solution
A radiation-resistant silica-based laser optical fiber preform core rod is developed, comprising activated ions like Yb3+, Er3+, co-doped ions such as Al3+, P5+, Ge4+, Ce3+, and F−, with a controlled —OD group mass ratio, treated with deuterium loading, high-energy irradiation, and thermal annealing to inhibit radiation-induced color centers and enhance radiation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Al or P co-doping is used to improve rare earth ion solubility and regulate refractive index, then the solubility of rare earth ions increases, but radiation-induced color centers form causing sharp increase in loss
Solution Approach 1:
The patent removes Al and P elements from the optical fiber composition to eliminate the source of radiation-induced color centers. By extracting these harmful elements, the invention achieves radiation resistance while maintaining rare earth ion solubility through alternative doping strategies using elements like F, Ge, and Si in controlled concentrations.
Solution Approach 2:
The patent changes the compositional parameters by using specific ratios of SiO2, GeO2, and F doping instead of traditional Al-P co-doping. This parameter change allows maintaining refractive index control and rare earth solubility while avoiding radiation-induced color center formation, achieving both solubility improvement and radiation resistance.
2Reliability
If Ce doping is increased to improve radiation resistance, then radiation resistance improves, but refractive index increases sharply and beam quality deteriorates
Solution Approach 1:
The patent optimizes Ce doping concentration to a specific range (0.01-0.1 mol%) rather than using high concentrations. This parameter optimization achieves sufficient radiation resistance while controlling refractive index changes, thereby maintaining beam quality. The invention balances radiation protection with optical performance through precise compositional control.
3Reliability
If hydrogen-loading pre-treatment is applied to optical fiber, then radiation resistance improves, but background loss increases and mechanical strength decreases
Solution Approach 1:
The patent applies preliminary deuterium loading treatment to the optical fiber preform before drawing. This preliminary action introduces deuterium atoms that form strong Si-OD bonds, which are more radiation-resistant than Si-OH bonds. The deuterium loading is performed at controlled temperature and pressure to achieve sufficient radiation protection without excessive background loss or mechanical strength reduction.
4Object-affected harmful factors
If deuterium loading is performed to reduce radiation-induced loss, then radiation resistance improves, but processing complexity increases due to gas escaping problems
Solution Approach 1:
The patent performs deuterium loading treatment in a controlled inert atmosphere environment, typically using a sealed tube or autoclave system filled with deuterium gas. This approach prevents gas escaping problems by maintaining a closed system throughout the loading process. The inert environment ensures complete deuterium penetration while avoiding contamination and simplifying post-treatment handling compared to open-system methods.
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 approach significantly improves the radiation resistance and laser slope efficiency of rare earth-doped optical fibers by reducing radiation-induced color centers and background loss, ensuring stable performance in vacuum environments for extended periods.
Implementation Method 1
pre-treatment process of the preform; The optical fiber itself is pre-treated with hydrogen-loading or deuterium-loading
Implementation Method 2
laser or amplifier will face harsh ionization radiation (such as protons, electrons, X-rays and gamma rays) during space missions
Implementation Method 3
the formation of Al or P-related color centers caused by ionization radiation
Implementation Method 4
no subsequent thermal bleaching or photo bleaching treatment
Data Source
AI summary
A radiation-resistant laser optical fiber preform core rod at least includes one type of activated ion (Yb3+, Er3+) and one or more types of co-doped ion (Al3+, P5+, Ge4+, Ce3+, F−), and —OD group of 16-118 ppm. Irradiation resistance of core rod glass can be effectively improved by sequentially performing pre-treatments, i.e. deuterium loading, pre-irradiation and thermal annealing on a preform core rod. Electron paramagnetic resonance test shows that, under the same radiation condition, the radiation induced color center concentration in a preform core rod treated by the method above is lower than in an untreated core rod by one or more orders of magnitude. The obtained core rod can be used for preparing a radiation-resistant rare earth-doped silica fiber, and has the advantages of high laser slope efficiency, low background loss, being able to be used stably in a vacuum environment for a long time, for example.