RU2463264C2 - OPTICAL GLASS, CAPABLE OF LUMINESCENCE IN 1000-1700 nm RANGE, METHODS OF PRODUCING SAID GLASS (VERSIONS) AND FIBRE LIGHT GUIDE - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to laser glass and fibre light guides. Disclosed is optical glass, capable of luminescence in the 1000-1700 nm range when excited by radiation in the 400-900 nm wavelength range; the main glass-forming component in the glass is P₂O₅ and/or B₂O₃, and the luminescence source is bismuth in a subvalent state, wherein content of bismuth in terms of Bi₂O₃ ranges from 0.001 to 50 mol %. To obtain optical glass, a P₂O₅ and/or B₂O₃ source is mixed with a bismuth (III) source; the obtained mixture is heated at a rate of 0.1-2°C per minute to temperature 400-600°C; synproportioning of bismuth metal and the bismuth (III) source is carried out while heating to temperature 800-1100°C at a rate of 10-12°C per minute; the melt is cooled to solid state and then annealed. Bismuth metal is additionally introduced into the process after heating the mixture to 400-600°C or is obtained in the glass production process. In another version of the method, the mixture heated to 400-600°C is cooled to room temperature and the solidified melt is heated for 1-48 hours to temperature 700-1000°C in the atmosphere of an inert gas. The obtained optical glass can be used to make the core of a fibre light guide with a reflecting cladding, having refraction index lower than that of the core.

EFFECT: obtaining glass with stable luminescence in the 1000-1700 nm range using an optimum method.

17 cl, 14 ex, 2 tbl, 3 dwg

Description

The present invention relates to laser media, including laser glasses and optical fibers. In particular, the present invention relates to optical glass having luminescence in the range of 1000-1700 nm when excited by radiation with wavelengths in the range of 400-900 nm, as well as to methods for its production and a fiber waveguide containing such glass.

The development of fiber-optic communication lines has become an incentive for the creation of fiber broadband tunable radiation sources and optical amplifiers for the near infrared range. At the same time, an avalanche-like increase in the volume of transmitted information in telecommunication systems requires the active development of new spectral ranges. Of most interest is the spectral range 1000-1700 nm, in which fiber optic fibers based on quartz glass have the least loss. In this range, there are relatively narrow lines of amplification and laser generation of fiber optical fibers with a core doped with rare earth ions such as Nd ³⁺ , Yb ³⁺ and Er ³⁺ and some others, which, however, do not cover a wide spectral range 1150-1500 nm

Significant progress in mastering this spectral range of 1000-1700 nm is achieved by using bismuth doped glasses as an active medium, in which, sometimes under certain compositions and preparation conditions, long-lived (up to 1700 μs) broadband (up to 500 nm) luminescence with spectral the maximum position in the region of 1050-1420 nm, covering the spectral range from 900 to 2000 nm (Yasushi Fujimoto and Masahiro Nakatsuka, Jpn. J. Appl. Phys. Part 1, 40, L279 (2001); Yasushi Fujimoto and Masahiro Nakatsuka, Optical amplification in bismuth-doped silica glass, Appl. Phys. Lett. 82, 3325, 2003; IABufetov, EM Dianov, Bi- doped fiber lasers. Laser Physics Letters, Volume 6, Issue 7, Pages 487-504, 2009; Evgeny M. Dianov, Bi-doped glass optical fibers: Is it a new breakthrough in laser materials, J. Non-Cryst. Solids, 355 (2009), p. 1861-1864).

For example, it is known (US 2006/0199721, 09/07/2006) optical glass containing bismuth oxide, alumina and a glass-forming component, where the glass-forming component is preferably phosphorus oxide or boron oxide. A method for preparing glasses involves preheating the initial components of the composition at a temperature of at least 300 ° C and their subsequent melting at a temperature of 1250-1500 ° C. The source indicates that the obtained glass has luminescence in the infrared region of 900-1400 nm when excited by radiation of 400-900 nm.

JP 2009035448 (02.19.2009) discloses glass having luminescence sufficient for use in optical amplifiers; glass has the following composition, mol.%: 0.001-15% bismuth oxide, 0-60% (MgO + CaO + SrO + BaO), 1-60% ZnO, 0-5% Al ₂ O ₃ , 0-5% SiO ₂ , 38-64% B ₂ O ₃ and 1% or less (including 0%) Li ₂ O + Na ₂ O + K ₂ O + Cs ₂ O.

In patent RU 2302066 C1, June 27, 2007, optical oxide glass is described representing the core of a fiber waveguide for optical radiation at a wavelength in the range of 1000-1700 nm. Glass contains bismuth oxide, silicon oxides or germanium.

However, as was found by the authors, the optical glasses proposed in the cited sources do not always show the desired luminescence in the range of 1000-1700 nm, that is, the result of the luminescence of such glass is not guaranteed, but is random in nature. Accordingly, the resulting luminescent materials do not have stable and reproducible characteristics for industrial applications.

, где формальная степень окисления висмута

, а количество атомов висмута не превышает 9: 1≤n≤9.Numerous studies by the authors have shown that one of the reasons for guaranteed luminescence of bismuth-doped glasses is the presence of bismuth in such a glass in a subvalent state. By bismuth in the subvalent state or subvalent bismuth is meant compounds

where the formal oxidation state of bismuth

and the number of bismuth atoms does not exceed 9: 1≤n≤9.

As a rule, bismuth in the subvalent state is unstable. The authors were able to find out that the key factor affecting the stability of bismuth in the subvalent state in the environment of oxide glasses is the high acidity of the medium (note that high acidity enhances the stability of low oxidation states of other elements, such as iron, see, for example, Redox Behavior and Electrochemical Behavior of Glass Melts in Properties of Glass-Forming Melts Ed. By LDPye, A. Montenero, I. Joseph, p. 27, CRC Press, 2005). By environments with high oxo-acidity (Lux-Flood acidity) is meant those media in which the concentration of the free O ^2– ion is low. In the Lux Flood concept of oxyacidity, the O ^2- ion is the base in oxide melts and glasses, and accordingly, the substances that bind this ion act as oxyacids (Victor Cherginets, Oxoacidity: reactions of oxo-compounds in ionic solvents, in sen Comprehensive Chemical Kinetics, Elsevier, 2005). So, metaphosphate melts can act as oxoacids due to the binding reaction (for example, cyclotriphosphate ion):

Condensed boric acid oxoanions can react similarly, maintaining a high oxoacidity of the medium.

Thus, the technical task of the present invention is the creation of optical glass having stable luminescence in the range of 1000-1700 nm, the optimal methods for its production and fiber optic fiber based on such glass.

The problem is solved by creating an optical glass having luminescence in the range of 1000-1700 nm when excited by radiation with wavelengths in the range of 400-900 nm, characterized in that it contains P ₂ O ₅ and / or B ₂ O ₃ as glass-forming components and bismuth in a subvalent state as a source of luminescence.

As it turned out, such a glass composition provides guaranteed luminescence in the range of 1000-1700 nm due, firstly, to the content of subvalent bismuth and, secondly, to high acidity of the medium due to salts of condensed phosphoric and boric acids, which helps stabilize bismuth in the subvalent state.

The bismuth content in the proposed glass in terms of Bi ₂ O ₃ oxide is from 0.001% to 50% molar.

In one aspect of the present invention, the claimed glass further comprises at least one monovalent and / or divalent metal oxide and / or rare earth oxide Re ₂ O ₃ and / or oxide of an element selected from the group consisting of titanium, zirconium, hafnium , niobium, tantalum, tungsten, thorium.

Preferably, the oxide content of the monovalent or divalent metal is from 0 to 50%. The monovalent metal oxide is selected from the group consisting of Li ₂ O, Na ₂ O, K ₂ O, Rb ₂ O, Cs ₂ O. The divalent metal oxide is selected from the following group consisting of MgO, CaO, SrO, BaO, ZnO, CdO , PbO.

The introduction of monovalent metal oxides reduces the viscosity of the melt and facilitates the manufacture of the necessary optical elements from glass. At the same time, an excess of monovalent metal oxide leads to a decrease in the glass acidity, destabilization of bismuth subvalent states, and a decrease in IR luminescence.

The introduction of divalent metal oxides increases the resistance of glass to water and water vapor (chemical resistance). The stability of bismuth in the subvalent state practically does not change with the introduction of oxides of divalent metals. At the same time, their excess increases the working temperature of glass manufacturing and reduces the stability of glass with respect to crystallization.

Preferably, the content of rare earth oxide is from 0 to 30%. In this case, the rare earth metal is selected from the group consisting of scandium, yttrium, lanthanum. The introduction of oxides of scandium, yttrium, lanthanum increases the chemical resistance of glass. Excess of these oxides significantly increases the working temperature of glass manufacturing and increases the tendency to crystallization.

In accordance with one variant of the present invention, the method of producing the proposed glass is as follows:

they mix the glass-forming components and the bismuth (III) source, heat the resulting mixture in air at a rate of about 0.1-2 ° C per minute to a temperature of 400-600 ° C to remove gaseous products, obtain bismuth in a subvalent state by the reaction of the bismuth metal and source bismuth (III) when heated to a temperature of 800-1100 ° C at a rate of 10-12 ° C per minute, cooling the melt to a solid state, annealing and slowly cooling the resulting glass to room temperature.

In accordance with the proposed method, P ₂ O ₅ and / or B ₂ O ₃ or a source of P ₂ O ₅ and / or B ₂ O ₃ are used as glass-forming components.

In addition to phosphorus (V) oxide itself, phosphoric acid, acid phosphates of ammonium and alkali metals, pyrophosphates and acid pyrophosphates of ammonium and alkali metals, polyphosphates of ammonium and alkali metals, metaphosphates of ammonium and alkali metals can be used as a source of P ₂ O ₅ in the proposed method.

As a source of In ₂ About ₃ it is possible to use H ₃ IN ₃ .

As a source of bismuth (III), bismuth (III) oxide Bi ₂ O _{3 is} preferably used.

If glass is obtained that additionally contains other metal oxides (monovalent and / or divalent metal oxides, rare earth oxide), then the oxides themselves, hydroxides or their salts, for example, carbonates, phosphates, polyphosphates, pyrophosphates, metaphosphates, are used directly as sources of these oxides borates.

In accordance with the proposed method, metallic bismuth is introduced into the melt after heating the mixture to a temperature of 400-600 ° C.

Preferably, metallic bismuth is taken at a rate of 0.1-5 mg per 3 grams of a source of bismuth (III).

Thus, in accordance with the proposed method, bismuth in a subvalent state in the glass is obtained by synproportioning a bismuth source in oxidation state +3 (for example, bismuth (III) oxide Bi ₂ O ₃ ) and metallic bismuth in oxidation state 0.

The synproportionation reaction is a reaction in which a compound with one intermediate oxidation state is formed from compounds of an element with different oxidation states, for example:

. Примерами субвалентных соединений висмута, которые получают реакцией синпропорционирования, являются Bi⁺, Bi₂ ⁴⁺, Bi₅ ³⁺, Bi₉ ⁵⁺.The resulting subvalent compounds Bi _n ^{m +} have a formal oxidation state

. Examples of subvalent bismuth compounds that are obtained by the synproportionation reaction are Bi ⁺ , Bi ₂ ⁴⁺ , Bi ₅ ³⁺ , Bi ₉ ⁵⁺ .

The bismuth metal for the synproportionation reaction can be directly added to the initial mixture for glass preparation or obtained by preliminary reduction of bismuth (III) oxide with organic compounds, for example ethanol, ethylene glycol, acetone, ethyl acetate, hexane. Carbon monoxide, ammonia (including those released during the decomposition of ammonia salts included in the initial mixture for glass preparation) and hydrazine (including those released during the decomposition of hydrazine salts included in the initial mixture for glass preparation) are also used for reduction. .

Metallic bismuth can also be obtained by thermal decomposition of the starting components introduced into the mixture for the preparation of glass of certain bismuth (III) compounds, for example: bismuth hypophosphite, bismuth azide, bismuth acetate, bismuth tartrate, bismuth oxalate and other bismuth salts formed by organic acids. These bismuth compounds can be added directly to the initial mixture for glass preparation or after preliminary calcination to remove volatile components.

Note that in the known methods for producing optical glass, the temperature of the smelting process is quite high - at least 1250 ° C, which leads to corrosion of the crucible by molten glass, contamination of the glass with corrosion products, as well as to partial volatilization of the volatile components of the glass, for example P ₂ O ₅ , which in turn can lead to a decrease in the acidity of the medium and the deterioration of the luminescence characteristics. In the proposed method for producing glass, the operating temperatures are relatively low, which avoids the problems described above.

Luminescent subvalent bismuth compounds in glasses can be obtained not only by the synproportionation reaction, but also by thermal dissociation of oxide compounds Bi ³⁺ , for example:

In this case, the equilibrium towards bismuth in the subvalent state is shifted in accordance with the Le Chatelier principle by reducing the partial pressure of oxygen in the gas above the melt in an inert gas atmosphere.

Therefore, in accordance with another embodiment of the present invention, the method for producing optical glass according to paragraph 1 is as follows:

they mix glass-forming components and bismuth (III) oxide, heat the resulting mixture in air at a speed of 0.1-2 ° C per minute to a temperature of 400-600 ° C to remove gaseous products, cool the melt to a solid state, obtain bismuth in a subvalent state by heating solidified melt for 1-48 hours to a temperature of 700-1000 ° C in an inert gas atmosphere, slow cooling of the glass to room temperature.

The invention also provides an optical fiber comprising an optical glass core and a reflective cladding with a refractive index lower than the refractive index of the core, characterized in that the core contains glass according to Claim 1. Lower refractive index of the reflective clad than the core necessary to ensure the propagation of radiation along the fiber with low losses over long distances. The corresponding profile of the refractive index - in the core, the refractive index is higher than in the reflective sheath - provides the mode composition of the radiation (single-mode or multimode fiber), the concentration of radiation in the core and, ultimately, low losses.

So, for example, the reflective sheath can be made of silicone rubber or quartz glass alloyed with B ₂ O ₃ or F.

A fiber can be obtained in various ways, the description of which is presented below.

For example, a cylindrical billet of the proposed glass is pulled into a fiber optic fiber using a conventional exhaust system used to draw fiber optic fibers. So the core of the fiber is the proposed optical glass, and the reflective sheath is a cylindrical layer of silicone rubber deposited on a cylindrical glass core during the drawing process.

Alternatively, an optical fiber is obtained by drawing in a method according to which an initial mixture of components for preparing the proposed glass or glass itself is poured into the central crucible, and a mixture for preparing glass having a refractive index lower than the refractive index of the core glass is poured into the second crucible.

In addition, a fiber optic fiber can be obtained by the method of “head-tube”, in which a cylindrical head made of the proposed glass is placed in a glass tube with a refractive index lower than the refractive index of the head glass; after that, such a composite “stand-in-tube” construction is pulled into a fiber optic fiber using a conventional exhaust system, in which the core consists of stand glass and the reflective shell consists of tube glass.

Also, a preform for a fiber fiber is obtained using stratified melt technology, in which a solid cylindrical preform from the proposed glass and an outer cylindrical layer of glass are extruded from a layered melt of glasses (in each layer of glass of a certain composition and properties), the refractive index of which is lower than the refractive index of the inner cylinder; From this preform, a fiber optic fiber with a core of the proposed glass and a reflective sheath of glass with a refractive index lower than the refractive index of the core is drawn using a conventional exhaust installation.

The preform can also be obtained by chemical vapor deposition (e.g., modified chemical vapor deposition (MCVD), plasma gas deposition (PCVD and SPCVD), external gas deposition (OVD), and axial deposition from the gas phase (VAD)) upon receipt of the core layers of the preform, conditions are created that dope the glass with bismuth in the high-acid mode of the glass obtained from the gas phase, which helps stabilize bismuth in the subvalent state.

The preform can be obtained by deposition from the gas phase by one of the above methods, characterized in that during the manufacturing process of the core, the temperature regime is maintained, which ensures the production of porous glass of the core. After this, the preform is soaked in a solution of subvalent bismuth, then dried and melted, providing a high acidity regime, which helps to stabilize bismuth in the subvalent state of the glass core of the preform.

The billet obtained by one of the above methods, using a conventional installation for pulling optical fibers, is pulled into a fiber optical fiber with a core made of bismuth-doped glass having high oxoacidity stabilizing the bismuth subvalent state.

In the drawings, an apparatus for measuring IR luminescence is shown in FIG. 1; figure 2 and 3 - as examples, the luminescence spectra of glass obtained in accordance with Examples 3 and 9.

Installation for measuring infrared luminescence, the scheme of which is presented in FIG. 1, consists of a cw Nd-YAG laser emitting a second harmonic (λ = 532 nm, power - 7 mW, radiation beam diameter ≈ 5 mm) 1, filters 2, grade SZS25, cutting off laser radiation at the fundamental frequency and other wavelengths, except for the working length of 532 nm. The laser radiation is focused using a concave mirror 3 onto the sample 4. The radiation from the sample passes through a system of focusing lenses 5 and a filter 6 (IKS5 brand for cutting off exciting radiation) and falls on the entrance slit of the spectrometer 7 (entrance slit width 3 mm). The spectrum is recorded at the output of the spectrometer by a digital camera 8 cooled by liquid nitrogen based on the InGaAs line of photodiodes (sensitivity range 0.8-1.7 μm, temperature during the experiment -69 ° C, exposure time 2 sec), which registers the spectrum and transmits the spectrum data in digital view on a personal computer 9, on which the storage and processing of the obtained luminescence spectra takes place.

The present invention is illustrated by examples, which are not limiting:

Example 1 (known composition of glass).

A mixture of 10 molar parts of NH ₄ H ₂ PO ₄ , 5 molar parts of Al ₂ O ₃ and 1 molar part of Bi ₂ O _{3 is} mixed, placed in a corundum crucible. The mixture is slowly heated in air at a speed of 4 ° C per minute to a temperature of 1200 ° C. The mixture is kept at this temperature for another 4 hours. Then the melt is poured onto a heated steel plate. The frozen glass sample is annealed and processed. Luminescence of the obtained glass in the range of 1000-1700 nm was not observed.

Example 2

A mixture of 2 molar parts of KH ₂ PO ₄ , 1 molar part of Bi ₂ O ₃ and 6 molar parts of NH ₄ H ₂ PO _{4 is} carefully triturated and placed in a crucible made of porcelain, quartz or corundum. The mixture is slowly heated in air at a speed of 2 ° C per minute to a temperature of 600 ° C. During heating, the released ammonia creates a reducing medium, as a result of which part of bismuth from Bi ₂ O ₃ in the initial charge is reduced to a metallic state, forming a gray coating on the surface of the melt and on the walls of the crucible. Subsequently, the mixture is heated at a rate of 12 ° C per minute to a temperature of 900 ° C. In this case, metallic bismuth reacts with the melt, as a result of which, at first, the colorless melt acquires a pinkish-purple color (when cooled, the color changes to yellowish-orange). The melt is poured onto a heated steel plate, the resulting glass casting is annealed and the shape is given to it. The luminescence spectrum of the obtained sample is characterized by two maxima at approximately 1200 nm and 1300 nm. The resulting glass has a luminescence bandwidth at half height of 304 nm and, when excited by radiation of 500-900 nm, provides amplification of the optical signal in the range of 1050-1500 nm.

Example 3

A mixture of 10 molar parts of KH ₂ PO ₄ , 8 molar parts of MgO, 1 molar part of Bi ₂ O ₃ and 22 molar parts of NH ₄ H ₂ PO _{4 is} carefully ground and placed in a porcelain, corundum or quartz crucible. The mixture is slowly heated in air at a speed of 2 ° C per minute to a temperature of 600 ° C. In this case, the bulk of the gaseous products are removed. Subsequently, the mixture is heated at a rate of 12 ° C per minute to a temperature of 950 ° C. The melt is poured onto a heated steel plate. The frozen orange glass sample is annealed and processed to give it the desired shape. The luminescence spectrum of the obtained sample is presented in FIG. 2, it is characterized by two maxima at approximately 1200 nm and 1300 nm. The resulting glass has a luminescence bandwidth at half height of at least 289 nm and, when excited by radiation of 500-900 nm, provides amplification of the optical signal in the range of 1050-1500 nm.

Example 4

In accordance with the procedure of example 3, glasses are obtained by replacing MgO with an equimolar amount of ZnO, CaCO ₃ , SrCO ₃ , BaCO ₃ , PbO. Get samples of glass, painted in colors from yellow to brown. The characteristics of the luminescence spectra are presented in Table 1.

Example 5

A mixture of 1 molar part of Bi ₂ O ₃ and 10 molar parts of NH ₄ H ₂ PO _{4 is} carefully triturated and placed in a crucible made of porcelain, quartz or corundum. The mixture is slowly heated in air at a speed of 2 ° C per minute to a temperature of 600 ° C. After reaching this temperature, metallic bismuth is added at a rate of 1-5 mg per 3 grams of bismuth oxide and heating is continued to a temperature of 1050 ° C. at a rate of 12 ° C. per minute. Liquid glass is poured onto a heated steel plate, the casting is annealed and processed to give the desired shape. The luminescence spectrum of the obtained sample is characterized by two maxima at approximately 1200 nm and 1300 nm. The resulting glass has a luminescence bandwidth at half height of at least 295 nm and, when excited by radiation of 500-900 nm, provides amplification of the optical signal in the range of 1050-1500 nm.

Example 6

A mixture of 1 molar part of P ₂ O ₅ and 0.00001 molar parts of Bi ₂ O _{3 is} carefully ground in an atmosphere of dry inert gas. The mixture is placed in a quartz ampoule, the ampoule is filled with dry CO (carbon monoxide) at a pressure of 0.1 bar and soldered. The ampoule is heated at a speed of 2 ° C per minute to a temperature of 900 ° C, maintained at this temperature for 20 minutes and cooled to room temperature. Inside the ampoule, a slightly yellowish glass is obtained having luminescence with a maximum at approximately 1100 nm. The resulting glass has a luminescence bandwidth at half height of at least 150 nm and, when excited by radiation of 500-900 nm, provides amplification of the optical signal in the range of 1050-1300 nm.

Example 7

A mixture of 1 molar part of Bi ₂ O ₃ and 3 molar parts of H ₃ BO _{3 is} carefully triturated and placed in a corundum crucible. The mixture is slowly heated in air or in an inert gas atmosphere at a speed of 2 ° C per minute to a temperature of 600 ° C. After reaching this temperature, metallic bismuth is added at a rate of 0.1-5 mg per 3 grams of bismuth oxide and heating is continued to a temperature of 1100 ° C at a rate of 12 ° C per minute. Liquid glass is poured onto a heated steel plate, the casting is annealed and processed to give the desired shape. The luminescence spectrum of the obtained sample is characterized by two maxima at approximately 1200 nm and 1300 nm. The resulting glass has a luminescence bandwidth at half height of at least 302 nm and, when excited by radiation of 500-900 nm, provides amplification of the optical signal in the range of 1050-1500 nm.

Example 8

The preparation of glass is carried out in accordance with the procedure described in Example 5, replacing metal bismuth in the initial composition of the charge with an equimolar amount of bismuth acetate. The characteristics of the luminescence spectrum are presented in Table 1.

Example 9

Glass is produced as in example 5, but metallic bismuth is not added, and before heating, the crucible walls are treated with an organic solvent to create a reducing atmosphere during melting. As the solvent, monohydric or polyhydric alcohols are used, for example, ethanol, methanol, glycerin, ethylene glycol, as well as acetone, ethyl acetate, hexane, etc. The characteristics of the luminescence spectra are presented in Table 1.

Example 10

A mixture of 1 molar part of Bi ₂ O ₃ and 3 molar parts of H ₃ BO _{3 is} carefully triturated and placed in a corundum crucible. The mixture is slowly heated in air at a speed of 2 ° C per minute to a temperature of 600 ° C. Then the crucible is cooled to room temperature and get a solid melt. The crucible with the solidified transparent colorless glass is transferred to a furnace, allowing heating in an inert gas atmosphere, and heated for 2 hours to a temperature of 850 ° C in an argon atmosphere. Liquid glass is poured onto a heated steel plate and slowly cooled to room temperature. Get yellow-orange glass; the casting is processed to give it the necessary shape. The luminescence spectrum of the obtained sample is shown in FIG. 3 and it is characterized by two peaks at approximately 1200 nm and 1300 nm. The resulting glass has a luminescence bandwidth at half height of at least 289 nm and, when excited by radiation of 500-900 nm, provides amplification of the optical signal in the range of 1050-1500 nm.

Example 11

A mixture of 1 molar part of Bi ₂ O ₃ and 1 molar part of H ₃ VO _{3 is} carefully ground and placed in a crucible from corundum, the walls of which were previously treated with liquid ethanol. The mixture is slowly heated in air at a speed of 2 ° C per minute to a temperature of 600 ° C. Then the heating rate is increased to 10 ° C per minute and in this mode, the temperature is increased to 1100 ° C. The melt is maintained at this temperature for 20 minutes and poured onto a heated steel plate and cooled to a solid state.

A tan glass is obtained, the casting is annealed, processed to give the desired shape, and slowly cooled to room temperature. The luminescence spectrum of the obtained sample is characterized by a broad maximum centered at 1250 nm and 1300 nm. The resulting glass has a luminescence bandwidth at half height, 300 nm and, when excited by radiation of 500-900 nm, provides amplification of the optical signal in the range of 1050-1500 nm.

Example 12

A mixture of 40 molar parts of NH ₄ H ₂ PO ₄ , 18 molar parts of KH ₂ PO ₄ , 16 parts of ZnO, 1 part of Bi ₂ O ₃ and 2 parts of H ₃ BO _{3 is} carefully ground and placed in a porcelain, corundum or quartz crucible. The mixture is slowly heated in air at a speed of 2 ° C per minute to a temperature of 600 ° C and, upon reaching this temperature, further heating is carried out at a speed of 10 ° C per minute to a temperature of 1100 ° C. The melt is poured onto a heated steel plate and cooled to a solid state. Glass corresponds to the composition 0.8KZn (PO ₃ ) ₃ + 0.1KBi (PO ₃ ) ₄ + 0.1BPO ₄ . The frozen orange-brown glass sample is annealed, processed to give it the necessary shape, and slowly cooled to room temperature. The luminescence spectrum of the obtained sample is characterized by two maxima at approximately 1200 nm and 1300 nm. The resulting glass has a luminescence bandwidth at half height of at least 291 nm and, when excited by radiation of 500-900 nm, provides amplification of the optical signal in the range of 1050-1500 nm.

Example 13

A mixture of 20 molar parts of KH ₂ PO ₄ , 16 molar parts of MgO, 1 molar part of Bi ₂ O ₃ , 1 molar part of Y ₂ O ₃ and 44 molar parts of NH ₄ H ₂ PO _{4 is} carefully ground and placed in a porcelain, corundum or quartz crucible . The mixture is slowly (to avoid foaming during the evolution of gaseous products) heated in air at a speed of 2 ° C per minute to a temperature of 600 ° C. Upon reaching this temperature, heating is carried out at a rate of 10 ° C per minute to a temperature of 1100 ° C. The melt is poured onto a heated steel plate and cooled to a solid state. Glass corresponds to the composition 0.8KMg (PO ₃ ) ₃ + 0.1KBi (PO ₃ ) ₄ + 0.1KY (PO ₃ ) ₄ . The frozen orange glass sample is annealed, processed to give it the necessary shape and slowly cooled to room temperature. The luminescence spectrum of the obtained sample is characterized by two maxima at approximately 1200 nm and 1300 nm. The resulting glass has a luminescence bandwidth at half height of at least 288 nm and, when excited by radiation of 500-900 nm, provides amplification of the optical signal in the range of 1050-1500 nm.

Example 14

A mixture of 40 molar parts of KH ₂ PO ₄ , 32 molar parts of ZnO, 4 molar parts of Bi ₂ O ₃ , 1 molar part of TiO ₂ , ZrO ₂ , HfO ₂ or ThO ₂ and 88 molar parts of NH ₄ H ₂ PO _{4 is} carefully triturated and placed in a porcelain, corundum or quartz crucible. The mixture is slowly (to avoid foaming during the evolution of gaseous products) heated in air at a speed of 2 ° C per minute to a temperature of 600 ° C. Further heating to a temperature of 1000 ° C is carried out at a rate of 10 ° C per minute. The melt is poured onto a heated steel plate and cooled to a solid state. The frozen orange glass sample is annealed, processed to give it the necessary shape and slowly cooled to room temperature. The luminescence spectrum of the obtained sample is characterized by two maxima at approximately 1200 nm and 1300 nm. The resulting glass has a luminescence bandwidth at half height of at least 302 nm and, when excited by radiation of 500-900 nm, provides amplification of the optical signal in the range of 1050-1500 nm.

The generalized parameters of the obtained glasses are also presented in Tables 1 and 2.

Thus, the proposed glass allows you to get guaranteed, stable luminescence in the range of 1000-1700 nm due to bismuth in the subvalent state and its composition, which creates high oxoacidity, contributing to the stabilization of bismuth in this state.

Table 1. Composition, mol.% Example 1 Example 2 Example 3 Example 4 Example 4 Example 4 The total bismuth content in the glass (in terms of Bi ₂ O ₃ oxide) 6.25 16.667 3.333 3.333 3.333 3.333 P ₂ O ₅ 62.5 66.666 53.333 53.333 53.333 53.333 K ₂ O 0 16.667 16.667 16.667 16.667 16.667 MgO 0 0 26.667 0 0 0 Zno 0 0 0 0 0 0 Cao 0 0 0 26.667 0 0 Bao 0 0 0 0 26.667 0 Pbo 0 0 0 0 0 26.667 Al ₂ O ₃ 31.25 The presence of an optical absorption peak of 450-550 nm no Yes Yes Yes Yes Yes Characteristics of the fluorescence spectrum obtained upon excitation by radiation with a wavelength of 512 nm: Wavelength of fluorescence peaks, nm no ~ 1200, 1300 ~ 1200, 1300 ~ 1200, 1300 ~ 1200, 1300 ~ 1200, 1300 Fluorescence bandwidth at half height (nm) no 304 289 287 302 291

Table 2. Composition, mol.% Note 5 Note 6 Note 7 Note 8 Note 9 Note 10 Note eleven Note 12 Note 13 Note fourteen The total bismuth content in the glass (in terms of Bi ₂ O ₃ oxide) 16.667 0.001 25 16.667 16.667 25 fifty 1.786 1.667 3.306 B ₂ O ₃ 0 0 75 0 0 75 fifty 1.786 0 0 P ₂ O ₅ 83.333 99.999 0 83.333 83.333 0 0 51.786 53.333 52.893 K ₂ O 0 0 0 0 0 0 0 16.071 16.667 16.529 MgO 26.667 Zno 0 0 0 0 0 0 0 28.571 0 26.446 Y ₂ O ₃ 1.667 0 ZrO ₂ 0.826 The presence of an optical absorption peak of 450-550 nm Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Characteristics of the fluorescence spectrum obtained upon excitation by radiation with a wavelength of 512 nm: Wavelength of fluorescence peaks, nm ~ 1200, 1300 1100 ~ 1200, 1300 ~ 1200, 1300 ~ 1200, 1300 ~ 1200, 1300 ~ 1300 ~ 1200, 1300 ~ 1200, 1300 ~ 1200, 1300 Fluorescence bandwidth at half height (nm) 295 150 302 292 298 289 300 291 288 302

Claims (17)

1. Optical glass having luminescence in the range of 1000-1700 nm when excited by radiation with wavelengths in the range of 400-900 nm, characterized in that it contains P ₂ O ₅ and / or B ₂ O ₃ as glass-forming components and bismuth in the subvalent state as a source of luminescence, while the bismuth content is from 0.001 to 50 mol.%. 2. The glass according to claim 1, characterized in that it further comprises at least one monovalent and / or divalent metal oxide and / or rare earth oxide Re ₂ O ₃ and / or oxide of an element selected from the group consisting of titanium , zirconium, hafnium, niobium, tantalum, tungsten, thorium. 3. The glass according to claim 2, characterized in that the oxide content of monovalent and / or divalent metals is from 0 to 50 mol.%. 4. The glass according to claim 2, characterized in that the monovalent metal oxide is selected from the group consisting of Li ₂ O, Na ₂ O, K ₂ O, Rb ₂ O, Cs ₂ O. 5. The glass according to claim 2, characterized in that the divalent metal oxide is selected from the group consisting of MgO, CaO, SrO, BaO, ZnO, CdO, PbO. 6. Glass according to claim 2, characterized in that the rare-earth metal is selected from the group consisting of scandium, yttrium, lanthanum. 7. The glass according to claim 2, characterized in that the content of the oxide of the rare earth element is from 0 to 30 mol.%. 8. The method of producing optical glass according to claim 1, comprising mixing P ₂ O ₅ and / or B ₂ O ₃ or a source of P ₂ O ₅ and / or B ₂ O ₃ as glass-forming components and a source of bismuth (III), heating the resulting mixtures in air at a speed of about 0.1-2 ° C per minute to a temperature of 400-600 ° C to remove gaseous products, obtaining bismuth in a subvalent state by the reaction of the proportioning of bismuth metal and a bismuth source (III) when heated to a temperature of 800-1100 ° C at a rate of 10-12 ° C per minute, cooling the melt to a solid state, from firing and slow cooling of the resulting glass to room temperature, while metallic bismuth is added to the process or obtained in the process of obtaining glass. 9. The method according to claim 8, characterized in that bismuth (III) oxide Bi ₂ O _{3 is} used as the source of bismuth (III). 10. The method according to claim 8, characterized in that the metallic bismuth is introduced into the melt after heating the mixture to a temperature of 400-600 ° C. 11. The method according to claim 8, characterized in that the metallic bismuth is obtained by preliminary reducing the source of bismuth (III) with carbon monoxide, ammonia or hydrazine or organic compounds such as ethanol, ethylene glycol, acetone, ethyl acetate, hexane. 12. The method according to claim 8, characterized in that the metallic bismuth is obtained by thermal decomposition of bismuth acetate, bismuth tartrate or bismuth azide, bismuth hypophosphite or bismuth oxalate. 13. The method according to claim 11, characterized in that the metal bismuth is taken at the rate of 0.1-5 mg per 3 grams of a source of bismuth (III). 14. The method of producing glass according to claim 1, comprising mixing P ₂ O ₅ and / or B ₂ O ₃ or a source of P ₂ O ₅ and / or B ₂ O ₃ as the main glass-forming component and bismuth (III) oxide, heating the resulting mixtures in air at a speed of 0.1-2 ° C per minute to a temperature of 400-600 ° C to remove gaseous products, cooling the melt to a solid state, obtaining bismuth in a subvalent state by heating the solidified melt for 1-48 hours to a temperature of 700 -1000 ° C in an inert gas atmosphere, slow cooling of the glass to room temperature. 15. A fiber light guide comprising an optical glass core and a reflective cladding with a refractive index lower than the refractive index of the core, characterized in that the core contains glass according to claim 1. 16. The fiber light guide according to clause 15, wherein the reflective sheath is made of silicone rubber. 17. The fiber optic fiber according to clause 15, wherein the reflective sheath is made of quartz glass alloyed With ₂ About ₃ or F.

Images