阅读说明：本技术 一种稀土掺杂锗酸铋单晶光纤及包层方法 (Rare earth doped bismuth germanate single crystal optical fiber and cladding method ) 是由 李纳 徐军 徐晓东 王东海 王庆国 唐慧丽 吴锋 于 2020-10-23 设计创作，主要内容包括：本发明提供了稀土掺杂锗酸铋单晶光纤,包括外部包层和内部纤芯两部分,所述纤芯是由掺杂有一定浓度稀土离子的Bi-4Ge-3O-(12)单晶结构,所述包层为Bi-4Ge-3O-(12)结构,所述纤芯制备采用的原材料为稀土离子氧化物、Bi-2O-3、GeO-2,其中Bi-2O-3、GeO-2的摩尔比为1～2：3～4。本发明中设置有两层结构,包括外部包层和内部纤芯两部分,外部包层选用Bi-4Ge-3O-(12)制备的玻璃结构,内部纤芯为掺杂有稀土离子的Bi-4Ge-3O-(12)单晶结构,同时,还提供了上述光纤的制备方法,与现有技术相比,制备的光纤输出的激光更为高效、功率更高。(The invention provides a rare earth doped bismuth germanate single crystal optical fiber, which comprises an outer cladding and an inner fiber core, wherein the fiber core is formed by doping Bi with rare earth ions with certain concentration 4 Ge 3 O 12 A single crystal structure, the cladding being Bi 4 Ge 3 O 12 The structure is characterized in that the raw materials adopted for preparing the fiber core are rare earth ion oxide and Bi 2 O 3 、GeO 2 In which Bi 2 O 3 、GeO 2 The molar ratio of (A) to (B) is 1-2: 3 to 4. The invention is provided with a two-layer structure which comprises an external cladding and an internal fiber core, wherein the external cladding is Bi 4 Ge 3 O 12 The prepared glass structure has an internal fiber core of Bi doped with rare earth ions 4 Ge 3 O 12 The single crystal structure and the preparation method of the optical fiber are provided, and compared with the prior art, the prepared optical fiber has the advantages of high efficiency of laser output and high power.)

1. A rare earth doped bismuth germanate single crystal optical fiber is characterized in that: comprises an outer cladding and an inner core, the core is formed by doping Bi with a certain concentration of rare earth ions₄Ge₃O₁₂A single crystal structure, the cladding being Bi₄Ge₃O₁₂Structure of, theThe raw materials adopted for preparing the fiber core are rare earth ion oxide and Bi₂O₃、GeO₂In which Bi₂O₃、GeO₂The molar ratio of (A) to (B) is 1-2: 3 to 4.

2. The rare earth-doped bismuth germanate single crystal optical fiber according to claim 1, wherein: the rare earth ion is Yb³⁺、Nd³⁺、Tm³⁺Any one of, wherein when the raw material is Yb³⁺Ionic oxide of Yb³⁺The ion concentration accounts for 0.5-0.75 mol% of the fiber core; when the raw material is Nd³⁺When ionic oxide, Nd³⁺The ion concentration accounts for 0.2-0.35 mol% of the fiber core; when the starting material is Tm³⁺Ionic oxide, Tm³⁺The ion concentration is 3-5.5 mol% of the fiber core.

3. A preparation method of rare earth doped bismuth germanate single crystal optical fiber is characterized by comprising the following steps: the preparation method comprises the following specific steps of (1) preparing materials: with rare earth ion oxide, Bi₂O₃、GeO₂Weighing the raw materials according to the mol percentage and the mol ratio of the components in the claim 2, putting the raw materials into an agate mortar for grinding for 40-60min, and uniformly mixing the raw materials;

(2) pressing materials: pressing the raw materials prepared in the step (1) under the water pressure of 48-75MPa to form a rod shape;

(3) firing materials: putting the bar material in the step (2) into a muffle furnace, raising the temperature to 650-;

(4) growing a fiber core: preparing a rare earth ion doped silicate fiber core with the diameter of 1-2mm by a micro-pulling-down method or a laser heating base method;

(5) annealing the fiber core: the optical fiber is placed into a muffle furnace for annealing, and the temperature is kept constant at 650-880 ℃ for 24-48 hours.

(6) Processing a cladding pipe: by using Bi₄Ge₃O₁₂The structure is that raw materials are used, a hollow tube structure with a certain length and an inner diameter of 1.1-2.1mm is prepared;

(7) performing: inserting the fiber core in the step (5) into the hollow tube structure in the step (6) to obtain a prefabricated rod;

(8) drawing an optical fiber: and (4) fixing the preform in the step (7) on a drawing tower, and drawing the preform into an optical fiber at the temperature of 900-1050 ℃.

4. The method for preparing a rare earth-doped bismuth germanate single crystal optical fiber according to claim 3, wherein: in the step (4), the pulling rate of the micro-pulling-down method growth is as follows: 0.2-0.5 mm/min; the laser heating base method has the tensile degree of 3-20 mm/h.

5. The method for preparing a rare earth-doped bismuth germanate single crystal optical fiber according to claim 3, wherein: in the step (7), the initial length of the fiber core is the same as that of the hollow tube structure.

Technical Field

The invention belongs to the field of optical fiber materials, and particularly relates to a cladding method of a rare earth doped bismuth germanate single crystal optical fiber.

Background

At present, quartz (SiO) is widely used as the material of the crystal cladding₂). The fundamental function of the silica fiber is to confine and propagate a light beam, i.e., to confine light energy of a certain wavelength in a radial range of several to several tens of micrometers with low loss along the length of the silica fiber. The quartz fiber is suitable for transmitting signals and energy with various wavelengths from ultraviolet to infrared due to the wide transmission wavelength range (from near ultraviolet to near infrared, and the wavelength is from 0.38 to 2.1um), and has the advantages of large numerical aperture, large fiber core diameter, high mechanical strength, good bending property, easy coupling with a light source, and the like, so that the quartz fiber is used for sensing, spectral analysis, process control and laser transmission (particularly for transmitting He-Ne and Ar)⁺Ideal medium of ion and YAG laser), laser medical treatment, measurement technique, criminal investigation, information transmission and illumination. The sensor is widely applied to various fields such as electronics, medical treatment, bioengineering, material processing, sensing technology, national defense and military and the like. The quartz optical fiber is short for optical fiber, and is made of quartz glass (SiO) with high purity₂Is mainly composed ofRespectively) the fabricated fibrous waveguide structure. The fundamental function of the silica fiber is to confine and propagate light beams, i.e., to confine light energy of a certain wavelength in a radial range of several to several tens of micrometers with low loss along the length of the silica fiber.

However, quartz is not suitable for the cladding of lower melting point crystals, and BGO has been widely used in scintillation research, but its excellent physical properties, stable chemical properties and thermal properties make it a potential host material for high-quality rare earth ion doping to realize laser output. Wherein, the Nd: the BGO single crystal rod realizes the watt-level laser output. The rare earth ion doped optical fiber has the characteristic of optical amplification, can meet the requirements of optical communication, has rich rare earth ion energy levels, and can emit light with different wave bands in different substrate environments, so the rare earth doped crystal optical fiber has wide prospect.

Disclosure of Invention

In order to solve the defects of the prior art, the invention utilizes two powder raw materials of bismuth oxide and germanium oxide to grow single crystal and prepare glass, and uses BGO glass to realize the cladding of BGO single crystal, so that the single crystal fiber becomes a high-efficiency high-power laser output single crystal fiber, in particular to a rare earth doped bismuth germanate single crystal fiber which comprises an outer cladding part and an inner fiber core part, wherein the fiber core part is formed by doping Bi with certain concentration of rare earth ions₄Ge₃O₁₂A single crystal structure, the cladding being Bi₄Ge₃O₁₂The structure is characterized in that the raw materials adopted for preparing the fiber core are rare earth ion oxide and Bi₂O₃、GeO₂In which Bi₂O₃、 GeO₂The molar ratio of (A) to (B) is 1-2: 3 to 4.

Further, the rare earth ion is Yb³⁺、Nd³⁺、Tm³⁺Any one of, wherein when the raw material is Yb³⁺Ionic oxide of Yb³⁺The ion concentration accounts for 0.5-0.75 mol% of the fiber core; when the raw material is Nd³⁺When ionic oxide, Nd³⁺The ion concentration accounts for 0.2-0.35 mol% of the fiber core; when the starting material is Tm³⁺Ionic oxide, Tm³⁺Ion concentration3-5.5 mol.% of the core.

Meanwhile, the preparation method of the rare earth doped bismuth germanate single crystal optical fiber is also provided, and the specific preparation steps are

(1) Preparing materials: with rare earth ion oxide, Bi₂O₃、GeO₂Weighing the raw materials according to the mol percentage and the mol ratio of the components, grinding the raw materials in an agate mortar for 40-60min, and uniformly mixing the raw materials;

(2) pressing materials: pressing the raw materials prepared in the step (1) under the water pressure of 48-75MPa to form a rod shape; (3) firing: putting the bar material in the step (2) into a muffle furnace, raising the temperature to 650-; (4) growing a fiber core: preparing a rare earth ion doped silicate fiber core with the diameter of 1-2mm by a micro-pulling-down method or a laser heating base method;

(5) annealing the fiber core: the optical fiber is placed into a muffle furnace for annealing, and the temperature is kept constant at 650-880 ℃ for 24-48 hours.

(6) Processing a cladding pipe: by using Bi₄Ge₃O₁₂The structure is that raw materials are used, a hollow tube structure with a certain length and an inner diameter of 1.1-2.1mm is prepared;

(7) performing: inserting the fiber core in the step (5) into the hollow tube structure in the step (6) to obtain a prefabricated rod;

(8) drawing an optical fiber: and (4) fixing the preform in the step (7) on a drawing tower, and drawing the preform into an optical fiber at the temperature of 900-1050 ℃.

Further, in the step (4), the pulling rate of the micro-pulling-down growth method is as follows: 0.2-0.5 mm/min; the laser heating base method has the tensile degree of 3-20 mm/h.

Further, in the step (7), the length of the fiber core and the length of the hollow tube structure are the same.

Has the advantages that: the rare earth doped bismuth germanate monocrystal optical fiber provided by the invention is provided with a two-layer structure, and comprises an outer cladding and an inner fiber core, wherein the outer cladding is Bi₄Ge₃O₁₂Prepared glass structure, interiorThe fiber core is Bi doped with rare earth ions₄Ge₃O₁₂The single crystal structure and the preparation method of the optical fiber are provided, and compared with the prior art, the prepared optical fiber has the advantages of high efficiency of laser output and high power.

Drawings

FIG. 1 is a schematic view of the growth process in a micro pull-down furnace according to the present invention;

FIG. 2 is a schematic view of the growth process in a laser furnace according to the present invention;

fig. 3 shows the resulting optical fiber and cladding.

In the drawings: 21. a first cladding tube; 22. a first core; 1. a furnace body side wall heat preservation layer; 2. an induction coil; 3. performing a rod; 4. a crucible cover; 5. a seed rod; 6. an observation window; 7. a zirconia base; 8. a quartz support column; 9. a seed rod; 11. a second cladding tube; 12. a second core; 13. a laser beam.

Detailed Description

The rare earth doped bismuth germanate single crystal fiber comprises an outer cladding and an inner fiber core, wherein the fiber core is formed by doping Bi with rare earth ions with certain concentration₄Ge₃O₁₂A single crystal structure, the cladding being Bi₄Ge₃O₁₂The structure is characterized in that the raw materials adopted for preparing the fiber core are rare earth ion oxide and Bi₂O₃、GeO₂In which Bi₂O₃、GeO₂The molar ratio of (A) to (B) is 1-2: 3 to 4, preferably in a molar ratio of 2: 3.

The rare earth ion is Yb³⁺、Nd³⁺、Tm³⁺Any one of, wherein when the raw material is Yb³⁺Ionic oxide of Yb^{3 +}The ion concentration accounts for 0.5-0.75 mol.%, preferably 0.5 mol.% of the fiber core; when the raw material is Nd³⁺When ionic oxides are present, Nd³⁺The ion concentration accounts for 0.2-0.35 mol.%, preferably 0.3 mol.% of the fiber core; when the starting material is Tm³⁺Ionic oxide, Tm³⁺The ion concentration is 3-5.5 mol.%, preferably 4 mol.%, of the core.

As a specific embodiment of the inventionAlternatively, when the core of the optical fiber is prepared, the first core 22 is obtained by selectively using the growing device in the micro pull-down furnace of FIG. 1, and then Bi is prepared₄Ge₃O₁₂And a first cladding tube 21 of the structure, wherein a first fiber core 22 is placed inside the first cladding tube 21 to prepare a preform 3, and optical fiber drawing is performed to obtain a final optical fiber.

Alternatively, the laser heating pedestal method shown in FIG. 2 may be used to obtain the second fiber core 12, and then Bi is prepared₄Ge₃O₁₂And (3) placing a second fiber core 12 in the hollow second cladding tube 11 to prepare a prefabricated rod, and drawing the optical fiber to obtain the final optical fiber.

When the optical fiber with the structure is prepared, the specific method steps are as follows:

(1) preparing materials: with rare earth ion oxide, Bi₂O₃、GeO₂Weighing the raw materials according to the mol percentage and the mol ratio of the components, grinding the raw materials in an agate mortar for 40-60min, and uniformly mixing the raw materials;

(2) pressing materials: pressing the raw materials prepared in the step (1) under the water pressure of 48-75MPa to form a rod shape;

(3) firing materials: putting the bar material in the step (2) into a muffle furnace, raising the temperature to 650-;

(4) growing a fiber core: preparing a silicate fiber core doped with rare earth ions with the diameter of 1-2mm by a micro-pulling-down method or a laser heating base method;

(5) annealing the fiber core: and putting the optical fiber into a muffle furnace for annealing.

(6) Processing a cladding pipe: by using Bi₄Ge₃O₁₂The structure is that raw materials are used, a hollow tube structure with a certain length and an inner diameter of 1.1-2.1mm is prepared;

(7) performing: inserting the fiber core in the step (5) into the hollow tube structure in the step (6) to obtain a prefabricated rod;

(8) drawing an optical fiber: and (4) fixing the preform in the step (7) on a drawing tower, and drawing the preform into an optical fiber at the temperature of 900-1050 ℃.

In the step (4), the pulling rate of the micro-pulling-down method growth is as follows: 0.2-0.5 mm/min; the laser heating base method has the tensile degree of 3-20 mm/h. In the step (7), the initial length of the fiber core is the same as that of the hollow tube structure, and the fiber core and the hollow tube structure are used in the drawing process in the step (8), so that the production time is saved, and meanwhile, the cost can be saved.

The figures of the present invention are further described below in conjunction with the embodiments.

Example 1

Preparation of rare earth ion doped silicate optical fiber and its cladding method, selecting rare earth ion as Yb³⁺The preparation method specifically comprises the following steps:

(1) preparing materials: in Yb₂O₃、Bi₂O₃、GeO₂The raw materials are introduced according to the molar component ratio of 0.5:2:3 and put into an agate mortar for grinding for 50min, so that the raw materials are uniformly mixed;

(2) pressing materials: pressing the prepared raw materials into rods under the water pressure of 60 MPa;

(3) firing materials: and (3) putting the material rod into a muffle furnace, wherein the heating rate is 80 ℃/h, the constant temperature is 700 ℃, the constant temperature time is 20h, the cooling rate is 60-120 ℃/h, and cooling to the room temperature.

(4) Growing a fiber core: and preparing the rare earth ion doped silicate optical fiber with the diameter of 1mm by a micro-pulling-down method or a laser heating pedestal method. Wherein the pulling rate of the micro-pulling-down method growth is as follows: 0.2-0.35 mm/min. The laser heating pedestal method has the tensile degree of 3-12 mm/h.

(5) Annealing treatment: putting the optical fiber into a muffle furnace, and annealing at the constant temperature of 650 ℃ for 24 hours;

(6) processing a cladding pipe: by using Bi₄Ge₃O₁₂The structure is that a BGO glass tube is made of raw materials, the length of the BGO glass tube is the same as that of the bismuth germanate single crystal optical fiber, and the inner diameter is 1.1-2.1 mm;

(7) performing: inserting the bismuth germanate single crystal fiber core into a BGO glass tube to obtain a prefabricated rod;

(8) drawing an optical fiber: the optical fiber preform is fixed on a drawing tower, and the glass optical fiber preform is drawn into an optical fiber at a temperature of 900 ℃.

Example 2

Preparation of rare earth ion doped silicate optical fiber and its cladding method, selecting rare earth ion as Yb³⁺The preparation method specifically comprises the following steps:

(1) preparing materials: in Yb₂O₃、Bi₂O₃、GeO₂The raw materials are introduced according to the molar component ratio of 0.65:2:3 and put into an agate mortar for grinding for 60min, so that the raw materials are uniformly mixed;

(2) pressing materials: pressing the prepared raw materials into rods under the water pressure of 75 MPa;

(3) firing materials: and (3) putting the material rod into a muffle furnace, heating at the rate of 120 ℃/h, keeping the temperature at 800 ℃, keeping the temperature for 25h, cooling at the rate of 60-120 ℃/h, and cooling to room temperature.

(4) Growing a fiber core: the silicate optical fiber doped with rare earth ions with the diameter of 2mm is prepared by a micro-pulling-down method or a laser heating pedestal method. Wherein the pulling rate of the micro-pulling-down method growth is as follows: 0.3-0.5 mm/min. The laser heating base method has the tensile degree of 10-20 mm/h.

(5) Annealing treatment: putting the optical fiber into a muffle furnace, and annealing at the constant temperature of 650 ℃ for 24 hours;

(6) processing a cladding pipe: by using Bi₄Ge₃O₁₂The structure is that a BGO glass tube is made of raw materials, the length of the BGO glass tube is the same as that of the bismuth germanate single crystal optical fiber, and the inner diameter is 1.1-2.1 mm;

(7) performing: inserting the bismuth germanate single crystal fiber core into a BGO glass tube to obtain a prefabricated rod;

(8) drawing an optical fiber: and fixing the optical fiber preform on a drawing tower, and drawing the glass optical fiber preform into an optical fiber at the temperature of 1050 ℃.

Example 3

Rare earth ion doped siliconPreparation of acid salt optical fiber and its cladding method, rare earth ion is selected as Tm³⁺The preparation method specifically comprises the following steps:

(1) preparing materials: at Tm₂O₃、Bi₂O₃、GeO₂The raw materials are introduced according to the molar component ratio of 0.003:2:3, and are put into an agate mortar for grinding for 40min, so that the raw materials are uniformly mixed;

(2) pressing materials: pressing the prepared raw materials into rods under the water pressure of 48 MPa;

(3) firing materials: the charge bar was placed in a muffle furnace. The temperature rising rate is 150 ℃/h, the constant temperature is 650 ℃ (the constant temperature time is 30h), the temperature reduction rate is 60-120 ℃/h, and the temperature is reduced to the room temperature.

(4) Growing a fiber core: the silicate optical fiber doped with rare earth ions with the diameter of 1.5mm is prepared by a micro-pulling-down method or a laser heating pedestal method. Wherein the pulling rate of the micro-pulling-down method growth is as follows: 0.3-0.5 mm/min. The laser heating base method has the tensile degree of 10-20 mm/h.

(5) Annealing treatment: putting the optical fiber into a muffle furnace for annealing, and annealing at the constant temperature of 650-880 ℃ for 24-48 hours;

(6) processing a cladding pipe: by using Bi₄Ge₃O₁₂The structure is that a BGO glass tube is made of raw materials, the length of the BGO glass tube is the same as that of the bismuth germanate single crystal optical fiber, and the inner diameter is 1.1-2.1 mm;

(7) performing: inserting the bismuth germanate single crystal fiber core into a BGO glass tube to obtain a prefabricated rod;

(8) drawing an optical fiber: the glass optical fiber preform is fixed on a drawing tower and drawn into an optical fiber at a temperature of 1000 ℃.

Example 4

Preparation and cladding method of rare earth ion doped silicate optical fiber, selecting rare earth ion as Nd³⁺The preparation method specifically comprises the following steps:

(1) preparing materials: by Nd₂O₃、Bi₂O₃、GeO₂The raw materials are introduced according to the molar component ratio of 0.003:2:3 and put into an agate mortar for grinding for 55min, so that the raw materials are obtainedMixing uniformly;

(2) pressing materials: pressing the prepared raw materials into rods under the water pressure of 68 MPa;

(3) firing, namely putting the material rod into a muffle furnace, wherein the heating rate is 150 ℃/h, the constant temperature is 650 ℃ (the constant temperature time is 30h), and the cooling rate is 60-120 ℃/h;

(4) growing a fiber core: the silicate optical fiber doped with rare earth ions with the diameter of 1.6mm is prepared by a micro-pulling-down method or a laser heating pedestal method. Wherein the pulling rate of the micro-pulling-down method growth is as follows: 0.3-0.5 mm/min. The laser heating base method has the tensile degree of 10-20 mm/h.

(5) Annealing treatment: putting the optical fiber into a muffle furnace for annealing, and annealing at the constant temperature of 650 ℃ for 24 hours;

(6) processing a cladding pipe: by using Bi₄Ge₃O₁₂The structure is that a BGO glass tube is made of raw materials, the length of the BGO glass tube is the same as that of the bismuth germanate single crystal optical fiber, and the inner diameter is 1.1-2.1 mm;

(7) performing: inserting the bismuth germanate single crystal fiber core into a BGO glass tube to obtain a prefabricated rod;

(8) drawing an optical fiber: the optical fiber preform is fixed on a drawing tower, and the glass optical fiber preform is drawn into an optical fiber at a temperature of 980 ℃.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.