Preparation method of high-rare-earth-doped low-loss low-numerical-aperture glass optical fiber
By adding letetium oxide and other lanthanide oxides to the cladding and core of the glass fiber and optimizing the process flow, the problems of increased loss and deterioration of laser performance of high-risk earth doped glass fibers are solved, and high-risk earth doped glass fibers with low loss and low numerical pore size are achieved.
Patent Information
- Application Number
- CN202510356021.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-25
- Publication Date
- 2025-06-27
AI Technical Summary
The existing highly rare earth doped glass fibers are prone to problems such as increased losses and deterioration of laser performance under high doping conditions, and the rare earth ion clustering effect is serious.
By adding letetium oxide and other lanthanide oxides to the cladding and core of fiber glass, the glass composition design is optimized, and a specific process flow is adopted during the melting and drawing process, a high-resolution earth doped low-loss low-numerical pore size glass fiber is prepared.
Low loss and low numerical aperture under high rare earth doping are achieved, glass optical quality and fiber laser performance are improved, and rare earth ion clustering effect is reduced.
Smart Images
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Figure BDA0005327369670000051
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of optical glass materials, and particularly relates to a method for preparing a high rare-earth doped, low-loss and low numerical aperture glass optical fiber. Background Art
[0002] High rare-earth doped concentration and low transmission loss laser fibers are one of the core components of high-performance single-frequency fiber lasers. Due to the rigid and regular material structure of silica glass, the doping concentration of rare-earth elements therein is extremely limited, thus suppressing the possibility of high-quality silica fibers as high-performance single-frequency fibers. Multi-component glasses have more distorted and disordered structural units, so there is enough space to accommodate more rare-earth ions. In terms of high doping of rare-earth ions, multi-component glasses have irreplaceable advantages over silica glass. Laser outputs with wavelengths located at approximately 1 μm (ytterbium ions), 1.5 μm (erbium ions), 1.8 μm (thulium ions) and 2.0 μm (holmium ions) have been respectively achieved in multi-component glass fibers. Therefore, the research on multi-component glasses is expected to provide good material support for the generation of high-performance single-frequency fiber lasers.
[0003] The field strength and coordination number of rare-earth ions determine that they can only exist as network modifiers in the glass structure. Due to their relatively high market price, they are not regarded as indispensable components of the glass composition. Currently, the composition of multi-component optical fiber glasses usually includes the main components of the glass structure, alkali metals that can change the physical and chemical properties of the glass, and / or alkaline earth metal oxides, and / or intermediate oxides, and usually does not contain rare-earth oxides. In necessary cases, rare-earth oxides generally enter the glass composition as additives. In the case of low-concentration addition, the properties of the glass composition with added rare-earth are not much different from those of the original glass composition without added rare-earth, and the fiber-forming properties of the glass and the fiber loss change little. As the added rare-earth concentration gradually increases, the properties of the glass composition with added rare-earth are significantly different from those of the original glass composition without added rare-earth, resulting in a decrease in glass-forming properties and fiber-forming properties, and even inability to form fibers. Even if fibers can be formed, due to the increase in the added rare-earth concentration, the distance between rare-earth ions in the glass and the fiber becomes smaller, the interaction force increases, and the so-called "rare-earth ion clustering" effect is likely to occur, resulting in a sharp increase in fiber loss and a significant deterioration of laser performance.
[0004] In order to increase the doping concentration of rare-earth ions while improving the optical quality of the glass, reducing the glass matrix and subsequent fiber loss, and thus realizing the production of high-doped and low-loss glass fibers, it is necessary to consider rare-earth elements as the main components of the glass when designing the composition of the optical fiber glass. Summary of the Invention
[0005] In order to solve the above problems, the purpose of the present invention is to provide a method for preparing a high rare-earth doped, low-loss and low numerical aperture glass optical fiber.
[0006] To achieve the above object, the method for preparing a high rare earth doped low loss and low numerical aperture glass optical fiber provided by the present invention comprises the following steps carried out in sequence:
[0007] 1) Determining the cladding glass composition: The cladding glass is composed of a glass structure main unit component, at least one of an alkali metal oxide, an alkaline earth metal oxide, and an intermediate oxide capable of changing the physical and chemical properties of the glass, and lutetium oxide; wherein the weight ratio of the glass structure main unit component, the total weight of the alkali metal and / or alkaline earth metal and / or intermediate oxide, and the weight percentage of lutetium oxide is 45-65:15-40:2-30;
[0008] 2) Determining the core glass composition: The core glass is composed of a glass structure main unit component, at least one of an alkali metal oxide, an alkaline earth metal oxide, and an intermediate oxide capable of changing the physical and chemical properties of the glass, and a lanthanide element oxide; wherein the types and total weight percentages of the glass structure main unit components in the core glass and the cladding glass are exactly the same; the types and total weight percentages of the alkali metal oxide and / or alkaline earth metal oxide and / or intermediate oxide in the core glass and the cladding glass are exactly the same; the lanthanide element oxide is composed of at least one of other lanthanide element oxides other than lutetium oxide partially or completely replacing the lutetium oxide in the cladding glass, and the total weight percentage of the lanthanide element oxide in the core glass is exactly the same as the weight percentage of the lutetium oxide in the cladding glass;
[0009] 3) Preparation of the cladding glass and the core glass: Mix the above-mentioned cladding glass raw materials and core glass raw materials evenly in proportion, and place them in a high-temperature furnace preheated to the melting temperature for heating respectively to melt into a cladding glass liquid and a core glass liquid; then pour the above-mentioned cladding glass liquid and core glass liquid into a preheated cast iron mold respectively, and after being fully cured, put them into an annealing furnace to cool to room temperature and then take them out to make a block-shaped cladding glass and a core glass respectively;
[0010] 4) Preparation of the high rare earth doped low loss and low numerical aperture glass optical fiber: Process the above-mentioned block-shaped cladding glass and core glass into preforms respectively, and then put the preforms into an optical fiber drawing furnace for fiber drawing operation to finally realize the preparation of the high rare earth doped low loss and low numerical aperture glass optical fiber.
[0011] The glass structure main unit component is selected from at least one of silicon dioxide (SiO2), phosphorus pentoxide (P2O5), boron trioxide (B2O3), germanium dioxide (GeO2), tellurium oxide, and bismuth oxide.
[0012] The alkali metal oxide is selected from at least one of lithium oxide (Li2O), sodium oxide (Na2O), and potassium oxide (K2O); the alkaline earth metal oxide is selected from at least one of magnesium oxide (MgO), calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO); the intermediate oxide is selected from at least one of aluminum oxide (Al2O3), zinc oxide, and gallium oxide.
[0013] The lanthanide elements include lanthanum, cerium, praseodymium, neodymium (Nd), samarium, europium, gadolinium, terbium, dysprosium, holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).
[0014] The glass includes silicate glass, phosphate glass, borate glass, germanate glass, tellurite glass, bismuthate glass, and hybrid glasses of the above glasses, and the hybrid glasses include borophosphate glass, germanotellurite glass, tellurite bismuthate glass, etc.
[0015] The numerical aperture of the high rare earth doped low loss and low numerical aperture glass optical fiber is as low as 0.03.
[0016] The present invention has the following beneficial effects:
[0017] Based on the lanthanide contraction phenomenon, lutetium has the smallest ionic radius and molecular refraction among all 15 lanthanide elements. Compared with other lanthanide elements, the doping amount of lutetium in multi-component glass can be the highest, and the theoretical loss of the glass matrix caused by the same doping amount should be the lowest. Since these rare earth elements are extremely similar in physical and chemical properties, common rare earth luminescent elements, such as holmium, erbium, thulium, and ytterbium, are located in the adjacent positions to the left of lutetium in the periodic table and have the smallest differences in physical and chemical properties. The change in the physical and chemical properties of the glass caused by the equivalent substitution is the smallest, and the resulting numerical aperture can be reduced to a very low level. It is found in the experiment that lutetium oxide has a bubble suppression effect during the glass melting process, which helps to realize the preparation of high-quality optical glass. The presence of lutetium oxide in the glass can also greatly increase the thermal stability (anti-crystallization ability) of the glass, which is beneficial to the widening of the fiber drawing temperature range and the reduction of the fiber transmission loss.
[0018] Based on the unique physical and chemical properties of lutetium in the glass, the present invention creatively proposes a composition design method using lutetium oxide as an essential key component in the glass, supplemented by optimized glass melting, preform preparation, and fiber drawing processes, which can realize the preparation of high rare earth doped low loss and low numerical aperture glass optical fibers. This method is simple and reasonable, and has good effects, which can provide possibilities for the development and application of large core diameter single mode high performance glass optical fibers. Detailed Embodiments
[0019] The technical solutions of the present invention will be described in detail below in conjunction with embodiments:
[0020] Table 1 lists the actual addition amounts of the cladding glass raw materials and the core glass raw materials required to prepare 100 grams of glass in the following 4 examples. Here, R2O represents alkali metal oxide, RO represents alkaline earth metal oxide, and R2O3 represents intermediate oxide.
[0021] Glass type, raw material addition amount and numerical aperture in each example of Table 1
[0022]
[0023]
[0024] Example 1: Preparation of silicate glass optical fiber:
[0025] 1-1) When designing the composition of the cladding glass of the silicate glass optical fiber, first determine SiO2 as the main unit component of the glass, and then add alkali metal oxide, alkaline earth metal oxide, intermediate oxide, and Lu2O3. The addition amount of SiO2 is 51.75 grams, and the addition amounts of alkali metal oxide, alkaline earth metal oxide, and intermediate oxide are 18.70 grams, 7.44 grams, and 1.33 grams respectively, and the addition amount of Lu2O3 is 20.78 grams; when designing the composition of the core glass, determine SiO2 as the main unit component of the glass, and then add alkali metal oxide, alkaline earth metal oxide, intermediate oxide, and Lu2O3 and Tm2O3. The addition amounts and types of SiO2, alkali metal oxide, alkaline earth metal oxide, and intermediate oxide are the same as those of the cladding glass. The addition amount of Lu2O3 is 10.78 grams, and the addition amount of Tm2O3 is 10.00 grams to keep the total addition amount of rare earth element oxides in the core glass the same as the addition amount of Lu2O3 in the cladding glass.
[0026] 1-2) Weigh 51.75 g of SiO2, 1.56 g of Li2O, 4.85 g of Na2O, 12.29 g of K2O, 1.05 g of MgO, 4.39 g of CaO, 2.00 g of BaO, 1.33 g of Al2O3, and 20.78 g of Lu2O3 respectively according to the above weights, and mix them evenly in an agate mortar to make the cladding glass raw materials; weigh 51.75 g of SiO2, 1.56 g of Li2O, 4.85 g of Na2O, 12.29 g of K2O, 1.05 g of MgO, 4.39 g of CaO, 2.00 g of BaO, 1.33 g of Al2O3, 10.78 g of Lu2O3, and 10.00 g of Tm2O3 respectively according to the above weights, and mix them evenly in an agate mortar to make the core glass raw materials; then put them into a high-temperature furnace preheated to 1600 °C with a high-purity atmosphere protection device together with the crucibles, heat them respectively to melt into cladding glass liquid and core glass liquid, and keep them at this temperature for 24 hours to allow all raw materials to react fully. After that, pour the cladding glass liquid and core glass liquid into the preheated cast iron molds respectively. After being fully solidified, put them into an annealing furnace to cool to room temperature and then take them out to make colorless block-shaped cladding glass and core glass respectively;
[0027] 1-3) Process the cladding glass and core glass made in step 1-2) into a preform;
[0028] 1-4) Put the preform into a fiber drawing furnace with high-purity atmosphere protection for fiber drawing operation, and finally make a silicate glass optical fiber with a numerical aperture of about 0.032.
[0029] Example 2: Preparation of phosphate glass optical fiber:
[0030] 2-1) When designing the composition of the cladding glass of the phosphate glass optical fiber, first determine P2O5 as the main unit component of the glass, and then add alkaline earth metal oxides, intermediate oxides, and Lu2O3. The addition amount of P2O5 is 56.08 g, the addition amounts of alkaline earth metal oxides and intermediate oxides are 12.63 g and 3.84 g respectively, and the addition amount of Lu2O3 is 27.45 g; when designing the composition of the core glass, determine P2O5 as the main unit component of the glass, and then add alkaline earth metal oxides, intermediate oxides, and Yb2O3 and Er2O3; the addition amounts and types of P2O5, alkaline earth metal oxides, and intermediate oxides are the same as those of the cladding glass. The addition amount of Yb2O3 is 22.85 g, and the addition amount of Er2O3 is 4.60 g to keep the total addition amount of lanthanide oxides in the core glass the same as the addition amount of Lu2O3 in the cladding glass.
[0031] 2-2) Weigh 56.08 g of P2O5, 1.26 g of MgO, 1.76 g of CaO, 9.61 g of BaO, 3.84 g of Al2O3, and 27.45 g of Lu2O3 respectively according to the above weights, and mix them evenly in an agate mortar to prepare the cladding glass raw materials; weigh 56.08 g of P2O5, 1.26 g of MgO, 1.76 g of CaO, 9.61 g of BaO, 3.84 g of Al2O3, 22.85 g of Yb2O3, and 4.60 g of Er2O3 respectively according to the above weights, and mix them evenly in an agate mortar to prepare the core glass raw materials; then put them into a high-temperature furnace preheated to 1450 °C with a high-purity atmosphere protection device together with the crucible, and heat them respectively to melt into cladding glass liquid and core glass liquid, and keep them at this temperature for 24 hours to allow various raw materials to react fully. Then pour the cladding glass liquid and core glass liquid into the preheated cast iron molds respectively. After being fully cured, put them into an annealing furnace to cool to room temperature and then take them out to make block-shaped colorless cladding glass and purple core glass respectively;
[0032] 2-3) Process the cladding glass and core glass made in step 2-2) into a preform;
[0033] 2-4) Put the preform into a fiber drawing furnace with high-purity atmosphere protection for fiber drawing operation, and finally make a phosphate glass optical fiber with a numerical aperture of about 0.057.
[0034] Example 3: Preparation of borophosphate glass optical fiber:
[0035] 3-1) When designing the composition of the borophosphate glass optical fiber cladding glass, first determine P2O5 and B2O3 as the main glass unit components, and then add alkaline earth metal oxides, intermediate oxides, and Lu2O3. The addition amount of P2O5 is 57.42 g, the addition amount of B2O3 is 2.17 g, the addition amounts of alkaline earth metal oxides and intermediate oxides are 14.31 g and 3.81 g respectively, and the addition amount of Lu2O3 is 22.29 g; when designing the composition of the core glass, determine P2O5 and B2O3 as the main glass unit components, and then add alkaline earth metal oxides, intermediate oxides, and Lu2O3 and Nd2O3; the addition amounts and types of P2O5, B2O3, alkaline earth metal oxides, and intermediate oxides are the same as those of the cladding glass. The addition amount of Lu2O3 is 2.29 g, and the addition amount of Nd2O3 is 20.00 g to keep the total addition amount of lanthanide oxides in the core glass the same as the addition amount of Lu2O3 in the cladding glass.
[0036] 3-2) Weigh 57.42 g of P2O5, 2.17 g of B2O3, 14.31 g of BaO, 3.81 g of Al2O3, and 22.29 g of Lu2O3 respectively according to the above weights, and mix them evenly in an agate mortar to prepare the cladding glass raw materials; weigh 57.42 g of P2O5, 2.17 g of B2O3, 14.31 g of BaO, 3.81 g of Al2O3, 2.29 g of Lu2O3, and 20.00 g of Nd2O3 respectively according to the above weights, and mix them evenly in an agate mortar to prepare the core glass raw materials; then put them into a high-temperature furnace preheated to 1450 °C and equipped with a high-purity atmosphere protection device together with the crucible, and heat them separately to melt them into cladding glass liquid and core glass liquid. Keep them at this temperature for 24 hours to allow all raw materials to react fully, then pour the cladding glass liquid and core glass liquid into preheated cast iron molds respectively. After being fully cured, put them into an annealing furnace to cool to room temperature and then take them out to make block-shaped colorless cladding glass and purple core glass respectively;
[0037] 3-3) Process the cladding glass and core glass made in step 3-2) into a preform rod;
[0038] 3-4) Put the preform rod into a fiber drawing furnace with high-purity atmosphere protection for fiber drawing operation, and finally make a borophosphate glass optical fiber with a numerical aperture of about 0.061.
[0039] Example 4: Preparation of germanate glass optical fiber:
[0040] 4-1) When designing the composition of the cladding glass of the germanate glass optical fiber, first determine GeO2 as the main component of the glass, and then add alkali metal oxides, alkaline earth metal oxides, intermediate oxides, and Lu2O3. The addition amount of GeO2 is 49.28 g, and the addition amounts of alkali metal oxides, alkaline earth metal oxides, and intermediate oxides are 5.84 g, 15.05 g, and 6.40 g respectively, and the addition amount of Lu2O3 is 23.43 g; when designing the composition of the core glass, determine GeO2 as the main component of the glass, and then add alkali metal oxides, alkaline earth metal oxides, intermediate oxides, and Lu2O3 and Ho2O3; the addition amounts and types of GeO2, alkali metal oxides, alkaline earth metal oxides, and intermediate oxides are the same as those of the cladding glass. The addition amount of Lu2O3 is 8.43 g, and the addition amount of Ho2O3 is 15.00 g to keep the total addition amount of lanthanide oxides in the core glass the same as the addition amount of Lu2O3 in the cladding glass.
[0041] 4-2) Weigh 49.28 g of GeO2, 5.84 g of Na2O, 15.05 g of BaO, 6.40 g of Al2O3, and 23.43 g of Lu2O3 respectively according to the above weights, and mix them evenly in an agate mortar to prepare the cladding glass raw materials; weigh 49.28 g of GeO2, 5.84 g of Na2O, 15.05 g of BaO, 6.40 g of Al2O3, 8.43 g of Lu2O3, and 15.00 g of Ho2O3 respectively according to the above weights, and mix them evenly in an agate mortar to prepare the core glass raw materials; then put them into a high-temperature furnace preheated to 1600 °C with a high-purity atmosphere protection device together with the crucible, heat and melt them into cladding glass liquid and core glass liquid respectively, and keep them at this temperature for 24 hours to allow all raw materials to react fully. After that, pour the cladding glass liquid and core glass liquid into the preheated cast iron molds respectively. After full curing, put them into an annealing furnace to cool to room temperature and then take them out to make colorless block-shaped cladding glass and purple core glass respectively;
[0042] 4-3) Process the cladding glass and core glass made in step 4-2) into a preform;
[0043] 4-4) Put the preform into a wire drawing furnace with high-purity atmosphere protection for wire drawing operation, and finally make a germanate glass optical fiber with a numerical aperture of about 0.045.
Claims
1. A method for preparing a highly rare earth doped low loss and low numerical aperture glass optical fiber, characterized in that: The preparation method comprises the following steps performed in sequence: 1) Determining the composition of the cladding glass: the cladding glass is composed of a main unit component of the glass structure, at least one of an alkali metal oxide, an alkaline earth metal oxide and an intermediate oxide capable of changing the physical and chemical properties of the glass, and lutetium oxide; wherein the weight percentage ratio of the main unit component of the glass structure, the total weight of the alkali metal and / or alkaline earth metal and / or intermediate oxide, and the weight percentage of lutetium oxide is 45-65:15-40:2-30; 2) Determining the core glass composition: the core glass is composed of a main unit component of the glass structure, at least one of an alkali metal oxide, an alkaline earth metal oxide and an intermediate oxide capable of changing the physicochemical properties of the glass, and a lanthanide oxide; wherein the types and total weight percentages of the main unit components of the glass structure in the core glass and the cladding glass are exactly the same; the types and total weight percentages of the alkali metal oxide and / or alkaline earth metal oxide and / or intermediate oxide in the core glass and the cladding glass are exactly the same; the lanthanide oxide is composed of at least one lanthanide oxide other than lutetium oxide partially or completely replacing the lutetium oxide in the cladding glass, and the total weight percentage of the lanthanide oxide in the core glass is exactly the same as the weight percentage of the lutetium oxide in the cladding glass; 3) Preparation of cladding glass and core glass: the cladding glass raw materials and core glass raw materials are mixed evenly according to a certain proportion, and are respectively placed in a high-temperature furnace preheated to the melting temperature to be heated to form cladding glass liquid and core glass liquid; then the cladding glass liquid and core glass liquid are respectively poured into a preheated cast iron mold, and after being fully solidified, they are placed in an annealing furnace, cooled to room temperature, and then taken out to form block cladding glass and core glass respectively; 4) Preparation of highly rare earth doped low-loss low-numerical aperture glass optical fiber: The above-mentioned bulk cladding glass and core glass are processed into preform rods respectively, and then the preform rods are placed in a fiber drawing furnace for fiber drawing operation, and finally the preparation of highly rare earth doped low-loss low-numerical aperture glass optical fiber is achieved.
2. The method for preparing a highly rare earth doped low loss and low numerical aperture glass optical fiber according to claim 1, characterized in that: The main unit component of the glass structure is selected from at least one of silicon oxide, phosphorus oxide, boron oxide, germanium oxide, tellurium oxide and bismuth oxide.
3. The method for preparing a highly rare earth doped low loss and low numerical aperture glass optical fiber according to claim 1, characterized in that: The alkali metal oxide is selected from at least one of lithium oxide, sodium oxide and potassium oxide; the alkaline earth metal oxide is selected from at least one of magnesium oxide, calcium oxide, strontium oxide and barium oxide; and the intermediate oxide is selected from at least one of aluminum oxide, zinc oxide and gallium oxide.
4. The method for preparing a highly rare earth doped low loss and low numerical aperture glass optical fiber according to claim 1, characterized in that: The lanthanide elements include lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium.
5. The method for preparing a highly rare earth doped low loss and low numerical aperture glass optical fiber according to claim 1, characterized in that: The glass includes silicate glass, phosphate glass, borate glass, germanate glass, tellurate glass and bismuth glass, as well as mixed glasses of the above glasses, wherein the mixed glass includes borophosphate glass, germanium tellurate glass and tellurium bismuth glass.
6. The method for preparing a highly rare earth doped low loss and low numerical aperture glass optical fiber according to claim 1, characterized in that: The numerical aperture of the highly rare-earth-doped low-loss and low-numerical-aperture glass optical fiber is as low as 0.03.