JP5176136B2 - Optical doping material and optical amplification medium - Google Patents

Description

  The present invention relates to an optical doping material used for an optical amplifier that amplifies the intensity of signal light by pump light. In particular, in optical communication, optical interconnection, etc., the pump light and / or signal light is light. The present invention relates to an optical doping material used for an optical amplifier that propagates a fiber, an optical waveguide, and the like, and an optical amplification medium using the same.

  The role of optical communication technology in the advanced information society is very important, and the optical communication network covers the whole world, such as the Internet, domestic trunk lines, metro networks, and FTTH (Fiber To The Home). In the 1990s, with the introduction of an arrayed waveguide grating (hereinafter also referred to as “AWG”), wavelength division multiplexing (Wavelength multiplexing) that simultaneously transmits a large number of optical signals of different wavelengths in one optical fiber. Division Multiplexing (hereinafter also referred to as “WDM”) transmission system has been commercialized, and the construction of a large-capacity high-speed information communication network has been accelerated.

  One of the elemental technologies that has enabled commercialization of such a WDM transmission system is an optical amplification technology in a low-loss wavelength region (1.55 μm band) of a silica-based optical fiber. A technology for amplifying signal light in a wavelength band of 1550 nm using a semiconductor laser having a wavelength of 980 nm or 1480 nm as excitation light has already been commercialized. At this time, rare earth metal is doped in the optical fiber in which the signal light and the excitation light propagate, and the rare earth metal is excited by the excitation light, and then emitted in the 1550 nm band is superimposed on the signal light. It compensates for the signal light intensity that attenuates in the long-distance transmission process. As the rare earth metal doped in such an optical fiber, erbium is best known and widely used as an erbium-doped optical fiber amplifier. In addition to erbium, optical amplifiers using rare earth metals such as praseodymium and thulium are being actively developed according to the signal light wavelength band to be used.

  Generally, rare earth metals are doped in a silica-based optical fiber at a concentration of about 500 to 1000 ppm. Doping at a higher concentration causes the rare earth metals to agglomerate, and the energy of the rare earth metals excited by the excitation light moves to the adjacent rare earth metal before emitting the light corresponding to the signal light wavelength, and the desired light emission is achieved. It is known that a phenomenon that cannot be obtained occurs. This is called “concentration quenching” and affects the limit of doping rare earth metal into a silica-based optical fiber (see, for example, Non-Patent Document 1). For this reason, in order to amplify the signal light to a practically necessary intensity by the pumping light, a long optical fiber of about 100 m is required, which is a factor that hinders downsizing of the optical amplifier.

  On the other hand, with the aim of further increasing the functionality and cost, studies are underway to replace the quartz base material of the optical amplifier with an organic polymer base material. In general, rare earth metal-containing phosphors can be cited as rare earth metals that can be doped into organic polymers. Here, the phosphor is composed of three components: a host material, an activator, and an active assistant, and an oxide crystal or an ionic compound crystal is used as the host material. That is, the rare earth metal having fluorescence itself as an activator component is not directly doped into the organic polymer, but the rare earth metal is yttrium aluminum garnet (hereinafter also referred to as “YAG”) or the like. The purpose is achieved by once doping the oxide crystal and then crushing the crystal and mixing it into the organic polymer. However, when such a method is used, it is necessary to perform baking at a high temperature of about 1400 ° C. in order to form a YAG crystal, which increases the process cost. In addition, the particle size of the pulverized rare earth metal-containing phosphor is generally 1000 nm (1 μm) or more, and when dispersed at a high concentration for the purpose of application to an optical amplifier, the transparency decreases due to light scattering. It will not function as an optical transmission line. Therefore, there is a limit to the concentration at which the organic polymer can be doped with a rare earth metal-containing phosphor in a host material such as a crystal, and the optical amplifier is downsized as the doping amount increases, and an organic material is used as an optical transmission medium. It is impossible to achieve economic improvement by doing.

  As a technique for doping rare earth metals directly into organic polymers, (a) organic polymers formed by forming organic complexes of rare earth metals with organic ligands such as pyridines, phenanthrolines, quinolines, β-diketones, etc. An organic-inorganic composite synthesis method has been proposed, for example, in which a rare earth metal is dispersed therein, or (b) a material in which a rare earth metal is incorporated in an organic inclusion compound is dispersed in an organic polymer (for example, Patent Document 1, 2, refer to Non-Patent Document 2).

  The methods shown in the above (a) and (b) have the feature that the control range of the kind and concentration of rare earth metals can be expanded. Further, since the rare earth metal-containing dispersed phase thus obtained is in the molecular order, even if this dispersed phase is somewhat aggregated, it can be suppressed to a size of several nanometers to 20 nm. It has a feature that it can be doped at a high concentration without deteriorating the properties. However, when these methods are used, the excited state energy of the rare earth metal excited by the excitation light is directly linked to the rare earth metal by the Frank-Condon principle known in quantum mechanics. There is a problem that the light emission process inherent to the rare earth metal is inhibited (quenched).

  As means for solving such a problem, the excitation energy level of the rare earth metal is obtained by fluorinating or deuterating the CH group of the organic ligand or organic inclusion compound or organic polymer of the rare earth metal complex. There has been proposed a technique for suppressing quenching so that excitation energy levels in organic ligands and organic inclusion compounds do not overlap (see, for example, Patent Documents 3, 4, 5, 6, and Non-Patent Document 3). ).

  The method of fluorinating the CH group is effective in suppressing quenching while enabling the rare earth metal to be dissolved and dispersed in an organic medium at a high concentration. However, the fluoride or deuteride used as a raw material is effective. Since it is unreasonably expensive, it cannot bring about the effect of improving the economic efficiency of the optical transmission network expected by putting an optical amplifier using an organic polymer as a base material into practical use.

As a method for effectively doping a rare earth metal material into an organic polymer, a method using a rare earth metal-containing organic-inorganic composite has been proposed (for example, see Patent Document 7). An inorganic dispersed phase in which other transition metals are coordinated to rare earth metal ions via oxygen is used as a photo-doping material. However, when the organic polymer is molded and / or microfabricated due to its low thermal decomposition temperature. The problem remains that the rare earth metal-containing organic-inorganic composite is decomposed by heat and the expected amplification effect cannot be obtained.
Japanese Patent Laid-Open No. 05-088026 JP 2000-208551 A US Pat. No. 6,292,292 US Pat. No. 6,538,805 JP 2000-256251 A Japanese Patent Laid-Open No. 6-1914 JP 2006-222403 A Shoichi Sudo et al. "Optical fiber and optical fiber amplifier" Kyoritsu Shuppan (2006), page 172 C. Koeppen et al., "Journal of Optical Society of America, B", Vol. 14, 155 (1997) LH Slooff et al., Journal of Applied Physics, 91, 3955 (2002)

  As described above, methods for synthesizing organic-inorganic composites doped with rare earth metal materials in organic polymers by various methods have been proposed, but high-concentration doping of rare earth metal ions, suppression of quenching, optical transparency A material that can be applied to an optical amplifier while satisfying all of the four points of ensuring safety and improving thermal stability is not known.

  The present invention has been made in view of the circumstances as described above, and its purpose is (1) high concentration doping of rare earth metal ions, (2) suppression of quenching, and (3) optical transparency. And (4) to provide a material for photodoping satisfying improvement of thermal stability.

  As a result of intensive studies to solve the above problems, the present inventors have obtained a mixture obtained by reacting a rare earth metal salt and a metal alkoxide and a chelating agent in an organic solvent. It was found that the light doping material obtained is excellent in heat resistance.

  That is, the present invention is as follows.

(1) A light doping material obtained by mixing a complex obtained by reacting a rare earth metal salt with a metal alkoxide and a chelating agent in an organic solvent.

(2) The light doping material according to (1), wherein the chelating agent is a compound having at least two groups selected from the group consisting of an amino group, a hydroxyl group, and a carbonyl group.

(3) The photo-doping material according to (2), wherein the chelating agent is either a diketone or a tertiary amino alcohol.

(4) The rare earth metal is an element selected from a lanthanoid series, and the metal of the metal alkoxide is one selected from 3B group, 4B group, 4A group, 5A group, 6A group metal, rare earth metal, or The light doping material according to any one of (1) to (3) above, which is a combination of two or more elements.

(5) The photo-doping material according to any one of (1) to (4) above, wherein a thermal decomposition temperature by DSC measurement is 200 ° C. or higher.

(6) An optical amplifying medium in which an organic polymer having transparency at an excitation light wavelength and a signal light wavelength is doped with the light doping material according to any one of (1) to (5) above.

  The light doping material of the present invention can be highly doped with rare earth metal ions, can suppress concentration quenching, has optical transparency, and further has improved heat resistance. .

  The optical amplification medium of the present invention can effectively exhibit optical amplification.

  The light doping material of the present invention can have improved heat resistance by chemically modifying a complex obtained by reacting a rare earth metal salt with a metal alkoxide with a chelating agent.

<Composite>
First, a composite obtained by reacting a rare earth metal salt with a metal alkoxide will be described.

  The composite in the present invention has a structure in which oxygen of a metal alkoxide is coordinated with a rare earth metal ion, and is obtained, for example, by mixing the above rare earth metal salt and metal alkoxide in a solvent and refluxing. be able to.

  Examples of the solvent used for reflux for obtaining the complex include propylene glycol methyl ether (PGME), toluene, dimethylacetamide (DMAc) and the like.

  As a composite obtained by reacting a rare earth metal salt and a metal alkoxide used to constitute the light doping material of the present invention, one rare earth metal ion and the rare earth metal ion can be coordinated via oxygen. Any combination of metals may be used.

  The composite in the present invention is one in which one rare earth metal ion is coordinated with at least one other metal ion via oxygen. Here, what is important is to reduce as much as possible the presence of the same kind of rare earth metal ions at adjacent positions via oxygen. Therefore, the number and species of ligands composed of oxygen and other metal ions are not fixed. That is, one rare earth metal ion can be coordinated with one or more other metal ions via oxygen, and the number of ligands (other metal ions) can be rare earth metal ions, metal It depends on the metal species of the alkoxide.

  Although it does not specifically limit as said rare earth metal salt, For example, nitrate, sulfate, carbonate, chloride, formate, oxalate, acetate, chromium salt, etc. of rare earth metals can be used. Considering reduction of anionic impurities, etc., organic acid salts such as formate, acetate and oxalate are preferable. More preferably, acetate is used. The rare earth metal acetate usually contains water of crystallization and can be used as it is, depending on the type of other metal to be coordinated, but it is preferable to perform a dehydration treatment before the reaction. The rare earth metal salt other than acetate is also preferably dehydrated at 110 to 120 ° C. for about 1 to 2 hours.

  The rare earth metals are lanthanides (lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), Terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu)), scandium and yttrium. In the present invention, praseodymium (Pr ), Neodymium (Nd), erbium (Er) and thulium (Tm) are useful and preferred. In application to an optical amplifier in a wavelength region called 1.5 μm band (S band 1460-1530 nm, C band 1530-1565 nm, L band 1565-1625 nm) in optical communication, erbium, in particular, is a fluorescence having a central wavelength of 1533 nm. Since it has a light emission level, it is preferable.

  Further, the metal alkoxide is not particularly limited, but preferably, Group 3B (barium, aluminum, gallium, indium, thallium, etc.), Group 4A (titanium, zirconium, hafnium, etc.), Group 4B (silicon, Germanium, etc.) 5A group (vanadium, niobium, tantalum, etc.), 6A group (molybdenum, tungsten, etc.) or a rare earth metal to which one or more alkoxides having 1 to 5 carbon atoms are bonded, more preferably One or more alkoxide groups such as methoxide, ethoxide, propoxide, isopropoxide, butoxide are bonded to a metal such as aluminum, gallium, titanium, zirconium, niobium or tantalum. In particular, an aluminum alkoxide is preferable because, in an optical fiber for an optical amplifier using quartz glass as a base material and erbium as a dopant, co-addition of erbium and aluminum has a positive effect. Moreover, the said metal alkoxide may be individual or may be used together 2 or more types.

  The mixing ratio when the rare earth metal salt and the metal alkoxide are reacted may be appropriately determined according to the valence of the rare earth metal, and is not particularly limited. For example, when an erbium salt and an aluminum alkoxide are used. Each compound so that aluminum is 3 mol per 1 mol of trivalent erbium. Further, the solvent, reaction conditions, and the like used when the rare earth metal salt and the metal alkoxide are reacted may be appropriately determined so that the reaction between the two is completed, and is not particularly limited.

<Optical doping material>
The light doping material of the present invention can be improved in heat resistance by mixing and chemically modifying the complex with an chelating agent in an organic solvent. Since the rare earth metal ions and other metal ions are present in the vicinity, concentration quenching can be suppressed, and the organic polymer of rare earth metal ions can be highly doped.

  In addition, since rare earth metal ions and other metal ions are present in the vicinity, vibration quenching due to energy transfer between the CH group or OH group in the organic polymer and the rare earth metal is suppressed when used in an optical amplifier. can do.

  However, in a composite obtained by reacting a rare earth metal salt and a metal alkoxide, the thermal decomposition temperature is low, so when used in an optical amplifier, due to the heat when molding and / or microfabricating the organic polymer, A composite obtained by reacting a rare earth metal salt with a metal alkoxide is decomposed, and the expected amplification effect cannot be obtained.

  Therefore, the heat resistance can be improved by chemically modifying the complex using a chelating agent having at least two groups selected from the group consisting of an amino group, a hydroxyl group, and a carbonyl group in the molecule. .

  The chelating agent in the present invention is not particularly limited as long as it has two or more coordination sites capable of coordinating with a metal ion, and preferably a diketone and a tertiary amino alcohol.

  Examples of the diketone include diketones represented by the following formula I, and specific examples include acetylacetone, ethylacetylacetate, acetonylacetone, hexanedione, and the like.

R ¹ (CO) R ² (CO) R ³ Formula I
In the above formula, R ¹ and R ³ are alkyl groups; or alkyl groups containing functional groups such as a reactive vinyl group, allyl group, acryloyl group, imide group, and epoxy group; and R ² is alkylene It is a group.

More preferably, in the above formula, R ¹ and R ³ are C1 to C4 alkyl groups; or C1 to C1 containing functional groups such as a reactive vinyl group, allyl group, acryloyl group, imide group, and epoxy group. A C4 alkyl group; and R ² is a C1-C2 alkylene group.

  Examples of the tertiary amino alcohol used in the present invention include those represented by the following formula II, and specific examples include dimethylaminoethanol, diethylaminoethanol, dipropylaminoethanol, dimethylaminopropanol and the like. Quinidine is also preferably used.

上記式中、Ｒ^４、Ｒ^５は、アルキル基；又は反応性を有するビニル基、アリル基、アクリロイル基、イミド基、エポキシ基等の官能基を含有するアルキル基；であり、Ｒ^６はアルキレン基；又は反応性を有するビニル基、アリル基、アクリロイル基、イミド基、エポキシ基等の官能基を含有するアルキレン基である。

In the above formula, R ⁴ and R ⁵ are alkyl groups; or alkyl groups containing functional groups such as a reactive vinyl group, allyl group, acryloyl group, imide group, and epoxy group; and R ⁶ is alkylene. Or an alkylene group containing a functional group such as a reactive vinyl group, allyl group, acryloyl group, imide group or epoxy group.

More preferably, in the above formula, R ⁴ and R ⁵ are C1 to C4 alkyl groups; or C1 to C1 containing functional groups such as a reactive vinyl group, allyl group, acryloyl group, imide group, and epoxy group. C4 alkyl group; a and, ^{R 6} is an alkylene group of C1 -C2; or vinyl group having reactivity, an allyl group, an acryloyl group, an imido group, an alkylene of C1 -C2 containing a functional group such as epoxy group It is a group.

  The organic solvent used for mixing the complex and the chelating agent is not particularly limited, and any material can be used as long as the light doping material can be dispersed in the organic polymer and is soluble in the complex and the chelating agent. May be used. Examples of such an organic solvent include primary alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, and t-butanol; polyvalent resins such as ethylene glycol, propylene glycol, and glycerin. Alcohol: ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, propylene glycol-α-monomethyl ether, propylene glycol-α-monoethyl ether, etc. glycol ether; acetone, methyl ethyl ketone, etc. ketone; tetrahydrofuran, dioxane Cyclic ethers such as methyl acetate, ethyl acetate, propyl acetate, etc .; acetonitrile; aromatic compounds such as benzene, toluene, xylene; penta And hydrocarbon compounds such as hexane, hexane, heptane, cyclohexane; dimethylacetamide (DMAc) and the like.

  The mixing ratio of the chelating agent to the complex is not particularly limited, but it is preferably 3 equivalents or more with respect to 1 mole of the rare earth metal.

  The light doping material of the present invention can be obtained by mixing the complex and the chelating agent in the organic solvent, specifically stirring at 1 to 2 hours in the air or in a nitrogen atmosphere at 20 to 28 ° C. Can do. The obtained reaction solution is used as a solution or as a solid after removing the solvent by solvent separation or the like and mixed with an organic solvent containing an organic polymer.

  The light doping material of the present invention preferably has a thermal decomposition temperature of 200 ° C. or higher. More preferably, it is 230 ° C. or higher.

  The thermal decomposition temperature can be measured by differential scanning calorimetry.

  Using a differential scanning calorimetry (DSC) apparatus (for example, manufactured by PerkinElmer, product name: Pyris 1), the pyrolysis temperature is measured under the following measurement conditions. The material for light doping is dissolved in a solvent such as propylene glycol monomethyl ether or toluene so as to have a concentration of 10 to 30% by mass, 55 mg of the solution is taken in an aluminum pan, and kept at 130 ° C. for 30 minutes to remove the solvent. . Thereafter, after cooling to room temperature, the rate of temperature increase is 10 ° C./min. To 500 ° C. Measurement is performed in an open system.

<Optical amplification medium>
The optical amplifying medium of the present invention includes the above-described optical doping material and an organic polymer having transparency at the excitation light wavelength and the signal light wavelength.

  Note that it is also preferable to use a combination of different rare earth metals as the optical doping material used for the optical amplification medium.

  The organic polymer in the present invention is not particularly limited as long as it has transparency at the excitation light wavelength and the signal light wavelength, and can be dispersed without aggregating the light doping material. Those having substantial transparency in the wavelength band in which the expression of the optical function is utilized, particularly in the excitation light wavelength and the signal light wavelength, are used. Here, the wavelength band in which the expression of the optical function is used is not limited to the visible band from purple to red, but from ultraviolet rays and X-rays having a wavelength shorter than purple having a wavelength of about 400 nm, and red having a wavelength of about 750 nm. Alternatively, an infrared band having a long wavelength may be used.

  Examples of such an organic polymer include polymethyl methacrylate, polycyclohexyl methacrylate, polybenzyl methacrylate, polyphenyl methacrylate, polycarbonate, polyethylene terephthalate, polystyrene, polytetrafluoroethylene, poly-4-methylpentene-1, polyvinyl alcohol, Examples include polyethylene, polyacrylonitrile, styrene-acrylonitrile copolymer, polyvinyl chloride, polyvinyl carbazole, styrene-maleic anhydride copolymer, polyolefin, polyimide, epoxy resin, polysiloxane, polysilane, polyamide, and cyclic olefin resin. However, it is not limited to these. Moreover, these organic polymers may be used independently and can also be used in combination of 2 or more type.

  Those organic polymers dissolved in a solvent or melted by heating or the like can be mixed with the above-mentioned optical doping material and processed into a desired optical amplification medium. In addition, monomers, oligomers, and the like that are precursors of the desired organic polymer are selected as appropriate, and polymerized in the process of processing into the form of an optical amplifying medium using a mixture of the above-described materials for light doping as a starting material. You can also.

  Furthermore, the organic polymer used for the material of the optical amplification medium may have a functional group that promotes a reaction such as addition, crosslinking, or polymerization by light or heat in its main chain or side chain. Examples of such a functional group include a hydroxyl group, a carbonyl group, a carboxyl group, a diazo group, a nitro group, a cinnamoyl group, an acryloyl group, an imide group, and an epoxy group. By having these functional groups in the organic polymer, it is possible to improve the adhesion to a substrate or the like, and to perform an addition reaction with an organic material having functionality other than the optical doping material.

  The light amplification medium may contain additives such as stabilizers such as plasticizers and antioxidants, surfactants, dissolution accelerators, polymerization inhibitors, and colorants such as dyes and pigments. Furthermore, the optical amplifying medium uses organic solvents such as solvents (water, alcohols, glycols, cellosolves, ketones, esters, ethers, amides, hydrocarbons, etc., in order to improve moldability such as coating properties. Solvent).

  When the light doping material is dispersed in the organic polymer, the light doping material is preferably present with a diameter of 20 nm or less so as not to cause scattering.

  The optical amplification medium of the present invention can be used for an optical waveguide of an optical waveguide amplifier, a micro optical element of an optical amplifier or a laser, a temperature sensor material, or the like.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

<Production Example 1 of Composite>
In a 200 mL eggplant flask, 9.04 g of erbium acetate tetrahydrate was placed, dried for 2 hours under conditions of 110 ° C./vacuum (about 7 mmHg), and dehydrated to obtain 7.25 g of erbium acetate. Under a nitrogen atmosphere, 24.1 mL of propylene glycol monomethyl ether (PGME) was added to the obtained erbium acetate with stirring and dispersed. Next, 30.6 g of a propylene glycol monomethyl ether solution (concentration: 10.8% by mass) of aluminum tri-s-butoxide was added so that 6 equivalents of aluminum tri-s-butoxide per 1 mol of erbium erbium acetate. added.

  Thereafter, the mixture was stirred under reflux at 120 ° C. and reacted to obtain a transparent solution in about 5 minutes. After 2 hours, the reaction solution was cooled to room temperature to obtain a PGME solution (light pink transparent solution, 10.0% by mass) of an Er—Al complex.

<Production Example 2 of Composite>
A 200 mL eggplant flask was charged with 3.33 g of erbium acetate tetrahydrate, dried and dehydrated at 110 ° C./vacuum (about 7 mmHg) for 2 hours to obtain 2.76 g of erbium acetate. Under a nitrogen atmosphere, 14.5 mL of toluene was added to the obtained erbium acetate with stirring and dispersed. Subsequently, 12.3 g of a toluene solution of aluminum tri-s-butoxide (concentration 10.0% by mass) was added so that 6 equivalents of aluminum tri-s-butoxide was added to 1 mol of erbium erbium acetate.

  Then, when it reacted by stirring at 110 degreeC under reflux, it became a transparent solution in about 12 hours. After further stirring for 2 hours, the reaction solution was cooled to room temperature to obtain a toluene solution of Er-Al complex (light pink transparent solution, 10% by mass).

Example 1
<Production 1 of Photodoping Material>
5.0 g of the PGME solution (10.0% by mass) of the Er—Al complex obtained in Preparation Example 1 for the above complex was weighed, and 6 equivalents of acetonyl with respect to 1.39 mmol of erbium ions in the solution. Acetone (0.95 g / 8.34 mmol) was stirred while being slowly dropped using a syringe, and then stirred for 1 hour to obtain a PGME solution of the material 1 for photodoping.

<Measurement of thermal stability>
Using a differential scanning calorimetry (DSC) apparatus (for example, manufactured by PerkinElmer, product name: Pyris 1), the thermal decomposition temperature (Td) of the obtained photodoping material 1 was measured. As a result, Td = 218.7 ° C. The spectrum of the obtained DSC measurement is shown in FIG.

  The conditions for measuring the pyrolysis temperature are as follows.

55 mg of the above solution was taken in an aluminum pan and kept at 130 ° C. for 30 minutes for solvent removal. Then, after cooling to room temperature, it heated to 500 degreeC with the temperature increase rate of 10 degree-C / min. The measurement was performed in an open system.

(Example 2)
<Preparation of photo-doping material 2>
5.0 g of the PGME solution (10.0% by mass) of the Er—Al complex obtained in Production Example 1 of the above complex was weighed, and 3 equivalents of dimethylamino with respect to 1.39 mmol of erbium ions in the solution. Propanol (0.43 g / 4.17 mmol) was stirred while being slowly dropped using a syringe, and then stirred for 1 hour to obtain a PGME solution of the light doping material 2.

<Measurement of thermal stability>
When thermal stability was measured in the same manner as in Example 1, it was Td = 358.3 ° C. The spectrum of the obtained DSC measurement is shown in FIG.

(Example 3)
<Preparation of material for photodoping 3>
5.0 g of the PGME solution (10.0% by mass) of the Er—Al complex obtained in Production Example 1 of the above complex was weighed, and 6 equivalents of dimethylamino with respect to 1.39 mmol of erbium ions in the solution. Ethanol (0.86 g / 8.34 mmol) was stirred while being slowly dropped using a syringe, and then stirred for 1 hour to obtain a PGME solution of the material 3 for photodoping.

<Measurement of thermal stability>
When thermal stability was measured in the same manner as in Example 1, Td = 238.0 ° C. The spectrum of the obtained DSC measurement is shown in FIG.

Example 4
<Fabrication of Photodoping Material 4>
5.0 g of the PGME solution (10.0% by mass) of the Er—Al complex obtained in Production Example 1 of the above complex was weighed, and 12 equivalents of acetylacetone (1.39 mmol of erbium ion in the solution ( 1.67 g / 16.68 mmol) was slowly added dropwise using a syringe, followed by stirring for 1 hour to obtain a PGME solution of the material for photodoping 4.

<Measurement of thermal stability>
When thermal stability was measured in the same manner as in Example 1, Td = 213 ° C. The spectrum of the obtained DSC measurement is shown in FIG.

(Example 5)
<Fabrication of Photodoping Material 5>
A dimethylacetamide (DMAc) solution (10.0% by mass) of an Er—Al complex prepared by solvent substitution from the PEGME solution of the Er—Al complex obtained in Preparation Example 1 of the above complex was added to 0.0%. Weigh 6 g and stir while slowly dropping DMAc solution (20.0 mass%) of quinidine (0.06 g / 0.18 mmol) in 3 equivalents with respect to 0.06 mmol of erbium ions in the solution using a syringe. Then, the mixture was stirred for 1 hour to obtain a DMAc solution of the light doping material 5.

  The solvent substitution from the PGME solution to DMAc was performed as follows. From the Er-Al complex PGME solution, the solvent was distilled off at room temperature under vacuum conditions. DMAc was added and stirred under nitrogen atmosphere until uniform, to obtain a DMAc solution of Er-Al composite.

<Measurement of thermal stability>
When thermal stability was measured in the same manner as in Example 1, it was Td = 251.9 ° C. The spectrum of the obtained DSC measurement is shown in FIG.

(Example 6)
<Fabrication of Photodoping Material 6>
0.6 g of Er-Al complex DMAc solution (10.0 mass%) prepared by solvent substitution from the PEGME solution of Er-Al complex obtained in Preparation Example 1 of the above complex was weighed, A DMAc solution (20.0% by mass) of 6 equivalents of quinidine (0.12 g / 0.36 mmol) to 0.06 mmol of erbium ions in the solution was stirred dropwise with a syringe, and then 1 Stirring was performed for a time to obtain a DMAc solution of the light doping material 6.

<Measurement of thermal stability>
When thermal stability was measured in the same manner as in Example 1, Td was 282.0 ° C. The obtained DSC measurement spectrum is shown in FIG.

(Comparative Example 1)
<Measurement of thermal stability>
When the thermal stability was measured using the Er—Al composite before mixing the chelating agent instead of the light doping material 1 as the light doping material, Td was 197 ° C. The spectrum of the obtained DSC measurement is shown in FIG.

(Comparative Example 2)
<Preparation 7 of Photodoping Material>
0.6 g of the toluene solution (10.0% by mass) of the Er—Al complex obtained in Preparation Example 2 of the above complex was weighed, and 3 equivalents of methyl-based on 0.06 mmol of erbium ions in the solution. A toluene solution (33.3% by mass) of 2-phenylsulfinyl acetate (0.03 g / 0.18 mmol) was stirred while being slowly dropped using a syringe, and then stirred for 1 hour to obtain a photo-doping material 7 A toluene solution of was obtained.

<Measurement of thermal stability>
As the light doping material, the above-mentioned light doping material 7 was used instead of the light doping material 1, and the thermal stability was measured in the same manner as in Example 1. It was like that.

  The light doping material of the present invention is suitably used for an optical amplifier that amplifies the intensity of signal light with pumping light. An example of such an optical amplifier is an EDFA that has already been commercialized using a quartz-based inorganic material as a base material. However, the present invention enables the quartz-based inorganic material to be replaced with an organic polymer, thereby reducing the cost. To do.

  Further, since rare earth metal ions that can be doped only in the range of about 50 to 100 ppm can be doped by 10 mass% (100,000 ppm) or more, it is possible to reduce the size of an optical amplifier that can only be realized with a long length. For this reason, not only long-distance trunk optical fiber networks that have been used in the past, but also subscriber optical communication networks, etc. The effect can be demonstrated even in.

  Furthermore, in the optical interconnection field where research is going on to break down the bottleneck of information processing capacity and speed by using inter-board transmission between computers and intra-board transmission instead of conventional electronics. In addition, the effect of the present invention can be exhibited.

  The optical amplifying medium using the optical doping material of the present invention can be used not only for optical amplifier amplifiers but also for optical amplifiers, laser micro-optical elements, temperature sensor materials, and the like.

The spectrum of the DSC measurement of the material for light doping (Example 1) of this invention is shown. The spectrum of the DSC measurement of the material for light doping (Example 2) of this invention is shown. The spectrum of the DSC measurement of the material for light doping (Example 3) of this invention is shown. The spectrum of the DSC measurement of the material for light doping (Example 4) of this invention is shown. The spectrum of the DSC measurement of the material for light doping (Example 5) of this invention is shown. The spectrum of the DSC measurement of the material for light doping (Example 6) of this invention is shown. The spectrum of the DSC measurement of the material for optical doping (Comparative example 1) of this invention is shown.

Claims (4)

A composite having a structure in which oxygen of a metal alkoxide is coordinated to a rare earth metal ion , obtained by reacting a salt of a rare earth metal with a metal alkoxide ;
A chelating agent having at least two groups selected from the group consisting of an amino group, a hydroxyl group, and a carbonyl group ;
A material for light doping obtained by mixing the compound in an organic solvent and having the complex chemically modified with the chelating agent . The light doping material according to claim 1 , wherein the chelating agent is one of a diketone and a tertiary amino alcohol. The rare earth metal is an element selected from lanthanoid series, and the metal alkoxide is one or more selected from 3B group, 4B group, 4A group, 5A group, 6A group metal, rare earth metal light doping material according to claim 1 or 2 which is a combination of elements. Wavelength of light that can excite the rare earth metal (excitation light wavelength), and, an organic polymer having a transparency at the wavelength (the signal light wavelength) of light amplified by the rare earth metals, any of claims 1 to 3 An optical amplification medium doped with the optical doping material according to claim 1.

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