Radiation-resistant laser optical fiber preform core rod and preparation method therefor

Patent metadata

Field	Value
Publication number	US-12001052-B2
Application number	US-202017761075-A
Country	US
Kind code	B2
Filing date	Jul 1, 2020
Priority date	Sep 16, 2019
Publication date	Jun 4, 2024
Grant date	Jun 4, 2024

Abstract

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.

First claim

What is claimed is:

1. A radiation-resistant laser optical fiber preform core rod, wherein the preform core rod is Yb—Al—P—Ce—F co-doped silica glass, and a composition range of the preform core rod is: Yb 2 O 3 : 0.1˜0.2 mol %, Al 2 O 3 : 1.2˜1.9 mol %, P 2 O 5 : 2.6˜2.7 mol %, Ce 2 O 3 : 0.05˜0.07 mol %, F: 0.15˜1.1% mol %, SiO 2 : 94.03-95.9 mol %; the preform core rod also contains —OD group, and a mass ratio of the —OD group in whole substance is 118˜150 ppm; wherein the —OD group is introduced by sequentially carrying out gas loading-pre-irradiation-thermal annealing treatments on the preform core rod;
wherein the thermal annealing treatment diffuses deuterium gas molecules left over from chemical reaction from the preform core rod; and
radiation induced color center concentration of powder sample of the preform core rod after being irradiated by 1700 Gy gamma rays is 2.1*10 14 spins/mm 3 -120*10 14 spins/mm 3 .

2. The radiation-resistant laser optical fiber preform core rod according to claim 1 , wherein the mass of the powder sample is about 200 mg, and its particle size is less than 1 mm.

3. The radiation-resistant laser optical fiber preform core rod according to claim 1 , wherein it is made by the following steps:
S1: providing laser optical fiber preform core rod without pre-treatment;
S2: performing gas loading treatment on the preform core rod described in the step S1;
S3: performing high-energy rays pre-irradiation treatment on the preform core rod after the gas loading treatment;
S4: performing thermally annealing treatment on the preform core rod after the pre-irradiation.

4. The radiation-resistant laser optical fiber preform core rod according to claim 3 , wherein the laser optical fiber preform core rod without pre-treatment is prepared by:
1) using a Sol-Gel method combined with a vacuum sintering process; or,
2) using a modified chemical vapor deposition (MCVD) method combined with a solution doping process.

5. The radiation-resistant laser optical fiber preform core rod according to claim 3 , wherein the gas loading is pure deuterium gas or a mixed gas of deuterium gas and other gas, the volume ratio of the deuterium gas to the mixed gas is 50%-100%, the pressure of the gas loading treatment is 5.5-15 MPa, the temperature of the gas loading treatment is 100-280° C., the time of the gas loading treatment is 100-720 hours, and the other gas is nitrogen or inert gas.

6. The radiation-resistant laser optical fiber preform core rod according to claim 3 , wherein the gas loading is a mixed gas of deuterium gas and nitrogen gas.

7. The radiation-resistant laser optical fiber preform core rod according to claim 3 , wherein the high-energy rays are high-energy gamma (γ) rays or X-rays, the total dose of the pre-irradiation is 1-1000 kGy, and the dose rate of the pre-irradiation is 0.5-58.8 kGy/h.

8. The radiation-resistant laser optical fiber preform core rod according to claim 3 , wherein the temperature of the thermal annealing is 200-900° C., the time of the thermal annealing is 1-20 hours, the preform core rod is cooled down with the furnace after the thermal annealing is completed, and nitrogen is introduced as a protective gas during the thermal annealing.

9. A method for preparing the radiation-resistant laser optical fiber preform core rod according to claim 1 , which comprises the following steps:
S1: providing laser optical fiber preform core rod without pre-treatment;
S2: preforming gas loading treatment on the core rod described in the step S1;
S3: performing high-energy rays pre-irradiation treatment on the preform core rod after the gas loading treatment;
S4: performing thermally annealing on the preform core rod after the pre-irradiation treatment.

10. A radiation-resistant optical fiber, wherein it is prepared by the following steps:
A1: providing a radiation-resistant laser optical fiber preform core rod according to claim 1 ;
A2: grinding and polishing the preform core rod described in the step A1, and putting it into a silica sleeve, and obtaining a single-clad optical fiber preform by a tube rod method;
A3: drawing the preform core rod described in the step A2 by a high-temperature drawing tower, and coating two layers of organic glue on the surface of the optical fiber, wherein the inner layer of organic glue with low refractive index is used as the outer layer structure of the double-clad optical fiber, and the outer layer of organic glue with high refractive index mainly plays a protective role.

11. The radiation-resistant optical fiber according to claim 10 , wherein the background loss of the optical fiber at a wavelength of 1200 nm after irradiation with gamma rays with a dose rate of 0.34 Gy/min and a total dose of 700 Gy is 10-100 dB/km.

Assignees

• Shanghai Inst Optics & Fine Mech Cas

Inventors

• Shao Chongyun
• Hu Lili
• Yu Chunlei
• Wang Meng
• Jiao Yan
• Zhang Lei
• Wang Shikai
• Xu Xiaoqing

Classifications

• G02B6/02395 Primary

  Glass optical fibre with a protective coating, e.g. two layer polymer coating deposited directly on a silica cladding surface during fibre manufacture (G02B6/02052, G02B6/02057, G02B6/024, G02B6/032, G02B6/105, G02B6/14 take precedence; coating on fibre gratings G02B6/02104; multilayer core or cladding G02B6/036; reinforcing splice joints G02B6/2558; optical cables, i.e. comprising protective structures external to the protective coating such as a jacket or plural coated optical fibres G02B6/44; coating of glass to obtain optical fibres C03C25/104) · CPC title

• C03C25/1065

  Multiple coatings · CPC title

• G02B6/036

  core or cladding comprising multiple layers {(multicore optical fibres G02B6/02042; microstructured properties G02B6/02295; omniguide fibres G02B6/023)} · CPC title

• C03B2201/34

  doped with rare earth metals, i.e. with Sc, Y or lanthanides, e.g. for laser-amplifiers · CPC title

• C03C3/06 Primary

  with more than 90% silica by weight, e.g. quartz {(C03C3/045 takes precedence)} · CPC title