JP2006222403A - Optical amplifier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical amplifier using an organic inorganic complex containing rare earth metals in which (1) the rare earth metals can be heavily doped, (2) quenching is controlled, (3) optical transparency is ensured, and (4) economical efficiency is improved. <P>SOLUTION: An optical transmission channel consists of an organic polymer made by dispersing the rare earth metal. The rare earth metals form an inorganic dispersed phase in which another metal kind which makes configuration with at least one rare earth metal through oxygen. Preferably, the diameter of the inorganic dispersed phase, which consists of the rare earth metal and another metal kind is 0.1 to 1,000 nm which makes configuration therewith through oxygen. Preferably, the proportion of the rare earth metal is 90 wt% or less, by solid content conversion of total amount of the organic polymer and the rare earth metal dispersed phase. The metal which makes configuration with the rare earth metal through oxygen is one or more sorts of elements selected from group 3B, group 4A, and group 5A metals. As an example of a construction of the rare earth metal dispersed phase, a formation is shown by a rare earth metal salt and another metal alkoxide. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

    The present invention relates to an optical amplifier that amplifies the intensity of light (signal light) having a specific wavelength or wavelength band by using light (excitation light) having a wavelength or wavelength band different from this, and in particular, optical communication. The present invention relates to an optical amplifier that is preferably used in a state where excitation light and / or signal light propagates through an optical fiber, an optical waveguide, or the like in optical interconnection or the like.

As the advanced information society expands, the role of optical communication technology becomes more important as the amount of information increases and the information processing and transmission speed increase. An optical communication network is being built. In the 1990s, wavelength division multiplexing (WDM) transmission systems that simultaneously transmit a large number of optical signals with different wavelengths in one optical fiber were commercialized, and the construction of a large-capacity high-speed information communication network was accelerated. One of the elemental technologies that enables commercialization of such a WDM transmission method is an optical amplification technology. In an optical amplification technique that has already been commercialized, signal light having a wavelength of 1550 nm is used after being excited by a semiconductor laser having a wavelength of 980 nm, 1480 nm, or the like. At this time, a rare earth metal is doped in the optical fiber through which the signal light and the pumping light propagate, and the rare earth metal is excited by the pumping 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. Thus, erbium is best known as a rare earth metal doped in an optical fiber, and is widely used commercially as an erbium-doped optical fiber amplifier (EDFA). 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, the rare earth metal is doped in a silica-based optical fiber at a concentration of about 500 to 1000 ppm. When added at a concentration higher than this, the rare earth metals aggregate together, 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 The phenomenon that cannot be obtained occurs. This is called “concentration quenching” and affects the limit to which rare earth metals can be doped in a silica-based optical fiber. 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. (See Non-Patent Document 1.)
On the other hand, just as various lenses are replaced by glass from organic polymer molded products, optical amplifiers are not limited to long-distance trunk optical fiber networks by replacing quartz base materials with organic polymer base materials. Studies are underway to improve the economics by putting into practical use low-cost optical amplifiers that are required in the enormous amount of optical fiber transmission lines that are spreading to general households such as subscriber optical fibers. (See Patent Documents 1 to 5). However, rare earth metals have a problem that they are difficult to dissolve and disperse in an organic medium. For this reason, it is difficult to dope rare earth metals into an organic polymer base material that is economical, such as plastic optical fibers, making it difficult to improve the economics of optical transmission networks by putting low-cost optical amplifiers into practical use.

  In general, rare earth metal-containing phosphors can be cited as rare earth metals that can be doped into organic polymers. The phosphor here is composed of three components: a host material, an activator, and an activator, and an oxide crystal or an ionic compound crystal is used as the host material. (See Non-Patent Document 2.) That is, rather than directly doping an organic polymer with a rare earth metal having fluorescence itself as an activator component, the rare earth metal is oxidized with yttrium aluminum garnet (YAG) or the like. The object is achieved by once doping the product crystal and then crushing the crystal and mixing it into an 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 a rare earth metal-containing phosphor can be doped into an organic polymer in a host material such as a crystal, and downsizing of an optical amplifier due to a high concentration of doping and use of an organic material as an optical transmission medium It is impossible to achieve economic improvement by doing.

On the other hand, as a technique for doping rare earth metals directly into organic polymers, (a) organic complexes of rare earth metals with organic ligands such as pyridines, phenanthrolines, quinolines, β-diketones and the like are formed. Organic-inorganic composite synthesis methods have been proposed, such as dispersing rare earth metals in polymers, and (b) dispersing rare earth metals in organic inclusion compounds in organic polymers. (See Patent Documents 1 and 2 and Non-Patent Document 3.)
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. Moreover, since the rare earth metal-containing dispersed phase obtained in this way is in the molecular order, even if this dispersed phase is somewhat agglomerated, 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). (See Non-Patent Documents 4 and 5.)
As means for solving such problems, the rare earth metal excitation energy level and the organic ligand can be obtained by fluorinating or deuterating the CH group of the rare earth metal complex or organic inclusion compound. There has been proposed a technique for suppressing quenching so that excitation energy levels in organic inclusion compounds do not overlap. (See Patent Document 6, Non-Patent Documents 5 and 6). Such a technique is effective in suppressing quenching while allowing a rare earth metal to be dissolved and dispersed in an organic medium at a high concentration, but fluoride and deuteride used as a raw material are extremely expensive. Therefore, there remains a problem that it is impossible to bring about the effect of improving the economic efficiency of an optical transmission network expected by putting an optical amplifier using an organic polymer as a base material into practical use.

Japanese Patent Laid-Open No. 05-088026 JP 2000-208551 A US Patent 6292292 US Patent 65538805 US Patent 6751396 JP 2000-256251 A Ed. Sudo, "Erbium-doped fiber amplifier" Optronics (1999), p. 50 M. T. T. et al. Anderson et al., “PHOSPERS FOR FLAT PANEL EMISION DISPLAYES” (edited by BG Potter Jr et al., “Synthesis and Application of Lanthanide-Doped Materials”, page 79, The Ace. L. H. Slooff et al., Journal of Applied Physics, 83, 497 (1998). W. Siebland, The Journal of Chemical Physics, 46, 440 (1967) Y. Hasegawa et al., Chemistry Letters, (1999), p. 35. Hasegawa, “How to shine neodymium that does not shine in organic media?” Chemistry and Industry, Vol. 53, 126 (2000)

  As described above, methods for synthesizing organic-inorganic composites in which rare earth metal materials are doped into organic polymers by various methods have been proposed. However, high concentration doping of rare earth metals, suppression of quenching, optical properties have been proposed. A material that can be applied to an optical amplifier while satisfying all four points of ensuring transparency and economy 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, (2) suppression of quenching, (3) ensuring optical transparency. And (4) It is an object to provide an optical amplifier using a rare earth metal-containing organic-inorganic composite satisfying the improvement in economic efficiency.

The inventors of the present application have made extensive studies in order to achieve the above object. As a result, the inventors have found that the above object can be achieved by applying the organic-inorganic composite invented by the present inventors and filed in Japanese Patent Application No. 2004-197711, and have completed the present invention. That is, in the optical amplifier according to the present invention, the rare earth metal is composed of an inorganic dispersed phase in which another metal species is coordinated to the rare earth metal via oxygen, and this is used in combination with an organic polymer.
The optical amplifier according to claim 1 has an optical transmission path for propagating light having a specific wavelength or wavelength band (signal light) and light having a different wavelength or wavelength band (excitation light), In the optical amplifier in which the signal light intensity is amplified by the excitation light, the optical transmission path is made of an organic polymer in which a rare earth metal is dispersed, the rare earth metal being at least one kind of rare earth metal and another metal kind being oxygen. An inorganic dispersed phase formed by coordination via is formed.

  According to the above configuration, the rare earth metal can be highly doped into the organic polymer by coordinating the rare earth metal with other metal species via oxygen. Further, other metal species are coordinated via oxygen, thereby suppressing quenching due to energy transfer between the CH group or OH group in the organic polymer and the rare earth metal. At the same time, the metal species coordinated through oxygen suppresses concentration quenching associated with the proximity interaction and / or cluster formation of rare earth metals.

  The application of coordination compounds for the purpose of dispersing rare earth metals in organic polymers is also described in the prior art described above, and generally the coordination of organic compounds via oxygen or nitrogen capable of metal coordination. Is done. However, coordination with an organic compound as a ligand cannot suppress quenching due to energy transfer between the CH group or OH group in the organic polymer described above and the rare earth metal.

  If coordination with other metal species via oxygen is not performed, aggregation between rare earth metals occurs, and substantial dispersion in the organic polymer cannot be achieved. Even if it can be dispersed at a dilute concentration, the target rare earth metal-containing organic-inorganic composite cannot be formed due to the proximity interaction of rare earth metals and / or quenching accompanying cluster formation.

In the present invention, the rare earth metal is coordinated through oxygen bonded to other metal species. The inorganic dispersed phase of the present invention is schematically shown in FIG. As shown in the figure, the rare earth metal-containing organic-inorganic composite of the present invention includes an inorganic dispersed phase composed of a rare earth metal (1) in which another metal species (2) is coordinated via oxygen, and not shown. It is formed of a composite containing an organic polymer. Here, what is important in the dispersed phase is to reduce the presence of the same kind of rare earth metal at adjacent positions via oxygen as much as possible. Accordingly, the number and species of ligands composed of oxygen and other metal species are not fixed, and are not strictly limited to the molecular structure as shown in FIG.
When the organic polymer according to the present invention is used for an optical material or the like, it is desirably optically transparent (transmitting). Although the transmittance | permeability of an organic polymer will not be specifically limited if it is the range which has permeability | transmittance, it is preferable that it is 30-100% as a transmittance | permeability, and it is more preferable that it is 80-100%.
In addition, the inorganic dispersed phase containing the rare earth metal of the present invention can have an association structure as long as the presence of the same kind of rare earth metal can be reduced as much as possible in the adjacent position via oxygen. . Here, R in FIG. 1 represents an alkylcarbonyl group such as an alkyl group or an acetyl group, hydrogen, or the like.
The optical amplifier according to claim 2 is characterized in that the total diameter of the inorganic dispersed phase formed by coordinating a rare earth metal and another metal species thereto via oxygen is 0.1 to 1000 nm.
According to said structure, when the average diameter of the rare earth metal dispersed phase formed by coordinating other metals to the rare earth metal via oxygen is within the above range, the rare earth metal-containing organic-inorganic composite is transmitted. Since the same diameter is relatively small compared to the wavelength of light, high transparency of the rare earth-containing organic-inorganic composite can be ensured.
In order to solve the above-described problem, the light emitting device according to claim 3 has an organic polymer, a rare earth metal, and other metal species distributed through oxygen in terms of solid content. It is characterized by being 90% by weight or less of the total amount of the inorganic dispersed phase.
According to the above configuration, there is no light scattering loss due to secondary aggregation of rare earth metals in which other metal species are coordinated via oxygen, and high light transmission in an optical function application field deeply related to the present invention. Sex can be expressed. In this way, the ratio of the rare earth metal is 90% by weight or less of the total amount of the organic polymer, and the inorganic dispersed phase formed by coordination of the rare earth metal and other metal species to this via oxygen, in terms of solid content. If it is possible, the object of the present invention can be achieved, but depending on the use of the rare earth-containing organic-inorganic composite obtained by the present invention, it is necessary to suppress the absorbance of light transmitted through the rare-earth-containing organic-inorganic composite. Therefore, the ratio of the rare earth metal is 30% by weight or less of the total amount of the organic polymer, and the inorganic dispersed phase formed by coordination of the rare earth metal and other metal species with oxygen via the solid content. It is preferable.
In order to solve the above-described problem, the light emitting device according to claim 4 is one or two selected from the group 3B, 4A, and 5A metals as the metal coordinated to the rare earth metal through oxygen. It is characterized by being an element of more than species.
According to the above configuration, coordination of other metal species to the rare earth metal via oxygen is facilitated, and dispersion in the organic polymer and suppression of quenching in the light emission process of the rare earth metal are effectively expressed. It can be.
In the light-emitting device according to claim 5, an inorganic dispersed phase formed by coordinating a rare earth metal and another metal species to the rare earth metal via oxygen is formed of a rare earth metal salt and another metal alkoxide. It is characterized by.
With the above-described configuration, a dispersed phase in which other metal species are arranged to the rare earth metal via oxygen is efficiently formed.

As described above, the optical amplifier of the present invention includes an optical transmission line for propagating light having a specific wavelength or wavelength band (signal light) and light having a different wavelength or wavelength band (excitation light), rare earth metal And a rare earth metal-containing inorganic dispersed phase in which other metal species are coordinated via oxygen, and an organic polymer.
Therefore, (1) high concentration doping of rare earth metal is possible, (2) suppression of quenching, and (3) ensuring optical transparency can be achieved. In addition, high-temperature processes for forming host materials such as oxide crystals and expensive raw materials such as fluorides and deuterides for suppressing quenching are not required. (4) Benefits of ensuring economic efficiency Play.

The composition of the rare earth metal-containing organic-inorganic composite of the present invention may be any combination as long as it is a composite containing a rare earth metal, a metal capable of coordination with rare earth metal via oxygen, and an organic polymer. May be.
A method for forming an inorganic dispersed phase in which other metal species are coordinated to rare earth metal via oxygen is not particularly limited. For example, the inorganic dispersed phase is formed by a reaction between a rare earth metal salt and a metal alkoxide.
A composite of an inorganic dispersed phase and an organic polymer coordinated to another metal via oxygen is, for example, an inorganic dispersed phase and an organic polymer formed by the reaction of the above metal alkoxide and a rare earth metal salt. Can be adjusted by mixing and dispersing.

[Optical transmission line]
As the optical transmission line, one having a structure as shown in FIGS. 2A and 2B is used. Usually, FIG. 2A is called an optical fiber type, and FIG. 2B is called an optical waveguide type. In either case, light is confined and propagated in a portion (core) having a relatively high refractive index.

  In the optical amplifier (3), the signal light (4) propagates, but at the same time, the pumping light (5) also propagates. Usually, an optical coupler is connected before and after the optical amplifier, and pumping light is introduced into the optical transmission path through which the signal light (4) propagates to amplify the light, or after the optical amplification, the pumping light (5) is transmitted to the optical transmission line. Separate from.

  Further, the optical transmission line according to the present invention is formed of a rare earth metal-containing organic-inorganic composite.

[Rare earth metal]
Examples of rare earth metals include scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.
[Other metal species coordinated to rare earth metals via oxygen]
Other metal species are elements that can be coordinated to the rare earth metal via oxygen, and are not particularly limited as long as the target properties are not adversely affected. Preferably, Group 3B, Group 4A, and Group 5A metals are used. It is done. More preferably, aluminum, gallium, titanium, zirconium, niobium, or tantalum is used.

[Preparation of inorganic dispersed phase]
The method for forming the inorganic dispersed phase is not particularly limited as long as the metal coordination via oxygen to the target rare earth can be formed. For example, after mixing a rare earth raw material and a coordinating metal raw material, heat treatment and pulverization (starting raw materials are metal salts, hydroxides, oxides, etc.), can be coordinated with a rare earth metal salt There are a method in which a metal salt is dissolved in a solvent and then precipitated by hydrolysis, and a method in which an alkoxide of a metal capable of coordination with a rare earth metal salt is reacted in an organic solvent.

  In order to obtain a nanometer-sized rare earth metal dispersed phase, a method of reacting a rare earth metal salt with a coordinateable metal alkoxide in an organic solvent is preferably used. The solvent to be used is not particularly limited, and any solvent may be used as long as the final product having a coordination structure can be dispersed in the organic polymer. Examples of such solvents include primary alcohols such as methanol, ethanol, 1 propanol, 2 propanol, 1 butanol, 2 butanol, and t butanol; polyhydric alcohols such as ethylene glycol, propylene glycol, and glycerin; ethylene glycol monomethyl ether Glycol ethers such as ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, propylene glycol α-monomethyl ether, propylene glycol α-monoethyl ether; ketones such as acetone and methyl ethyl ketone; cyclic ethers such as tetrahydrofuran and dioxane; acetic acid Esters such as methyl, ethyl acetate and propyl acetate; Aromatic compounds such as acetonitrile, benzene, toluene and xylene; Pentane Hexane, heptane, hydrocarbon compounds such as cyclohexane; and the like are used.

  In order to form the coordination compound, it is possible to use a method of heating to the reflux temperature of the solvent, and this method is effective because it can accelerate the reaction rate in many cases. It is also possible to control the size of the inorganic dispersed phase by adding water to the resulting coordination product and hydrolyzing it.

  As starting materials for rare earth metals, mineral salts such as nitrates, sulfates, carbonates and chlorides, organic acid salts such as formates, acetates and oxalates, alkoxides and the like are used. Considering the reduction of anionic impurities, it is preferable to use organic acid salts such as formate, acetate and oxalate and alkoxides. 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 metal to be coordinated, but it is preferable to perform a dehydration treatment before the reaction.

  The functional group R of the dispersed phase shown in FIG. 1 is not particularly limited and is selected depending on the type of organic polymer to be combined. In order to improve the compatibility with the organic polymer, it can be selected for the purpose of imparting polymerizability with the organic polymer or a monomer component capable of forming the organic polymer. For example, as R, hydrogen, an alkyl group, a reactive vinyl group, an allyl group, a diazo group, a nitro group, a cinnamoyl group, an acryloyl group, an imide group, an epoxy group, a cyano group, or an alkyl group containing these functional groups , Alkylsilyl groups, alkylcarbonyl groups, and the like.

  In addition, if it can be homogeneously combined with the organic polymer to be combined, the activity of carboxylate groups such as poly (meth) acrylic acid, polyethylene glycol, polyethylene oxide, celluloses, hydroxyl groups, amino groups, amide groups, etc. A polymer having a functional group containing hydrogen can also be used.

  As a method of introducing the functional group R into the inorganic dispersed phase, <1> a method of introducing it by a reaction after forming the inorganic dispersed phase, or <2> a rare earth metal or / and a fourth periodic transition metal through oxygen in advance. There is a method of introducing an R group into an alkoxide as a starting material capable of coordinating with a rare earth metal salt and / or a fourth period transition metal salt.

  The compound to be reacted with the inorganic dispersed phase is not particularly limited as long as it can form the above-mentioned target structure. However, the method <1> has an active hydrogen such as a carboxylate group, a hydroxyl group, an amino group, an amide group at the terminal. Compounds, <2> include alkyl groups, reactive vinyl groups, allyl groups, diazo groups, nitro groups, cinnamoyl groups, acryloyl groups, imide groups, epoxy groups, cyano groups, or functional groups thereof Alkoxysilanes containing alkyl groups (R1R2R3SiOR4: R1 represents an alkyl group, a reactive vinyl group, an allyl group, a diazo group, a nitro group, a cinnamoyl group, an acryloyl group, an imide group, an epoxy group, a cyano group, or a functional group thereof. Contains alkyl group, R2 and R3 are alkyl group, reactive vinyl group, allyl group, diazo group, nitro group, Cinnamoyl group, acryloyl group, imide group, epoxy group, cyano group or alkyl group containing these functional groups, alkoxyl group, R4 is alkyl group), alkoxygermane (R1R2R3GeOR4: R1 is alkyl group, reactive vinyl Group, allyl group, diazo group, nitro group, cinnamoyl group, acryloyl group, imide group, epoxy group, cyano group or alkyl group containing these functional groups, R2 and R3 are alkyl groups, reactive vinyl groups, Allyl group, diazo group, nitro group, cinnamoyl group, acryloyl group, imide group, epoxy group, cyano group or alkyl group containing these functional groups, alkoxyl group, R4 is alkyl group) A compound capable of reacting with the phase is preferably used.

[Organic polymer]
The organic polymer is not particularly limited as long as it can disperse the rare earth metal coordinated with other metal species without agglomeration, but preferably the wavelength at which the expression of the optical function is utilized. A material having substantially transparency in the band is used. Here, the wavelength band in which the expression of the optical function is used is not limited to the visible band of purple to red, but ultraviolet light 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. It may be an infrared band having a longer wavelength.
Examples of such an organic polymer include polymethyl methacrylate, polycyclohexyl methacrylate, polybenzyl methacrylate, polyphenyl methacrylate, polycarbonate, polyethylene terephthalate, polystyrene, polytetrafluoroethylene, poly-4-methylpentene-1, and polyvinyl alcohol. , Polyethylene, polyacrylonitrile, styrene-acrylonitrile copolymer, polyvinyl chloride, polyvinyl carbazole, styrene-maleic anhydride copolymer, polyolefin, polyimide, epoxy resin, polysiloxane, polysilane, polyamide, cyclic olefin resin, etc. However, it is not limited to these. These organic polymers may be used alone or in combination of two or more. In addition, these organic polymers can be processed into a desired rare earth metal-containing organic-inorganic composite by dissolving them in a solvent or melted by heating, etc., but monomers, oligomers, which are precursors of organic polymers, Polymerization can also be performed in the process of processing a mixture of a monomer or oligomer and an organic polymer into a desired rare earth metal-containing organic-inorganic composite as a starting material.

  Furthermore, these organic polymers may have a functional group that promotes a reaction such as addition, crosslinking, or polymerization by light or heat in the 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.

  The organic polymer may contain additives such as stabilizers such as plasticizers and antioxidants, surfactants, dissolution accelerators, polymerization inhibitors, and colorants such as dyes and pigments. Furthermore, in order to improve molding processability such as coating properties, organic polymers are made of organic solvents such as solvents (water, alcohols, glycols, cellosolves, ketones, esters, ethers, amides, hydrocarbons). Solvent).

  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.

  <Preparation of Inorganic Dispersed Phase> Erbium acetate and tri-s-butoxyaluminum dehydrated in 2-butanol at 110 ° C. for 1 hour (Er / Al = 3 mol, total oxide equivalent concentration of Er and Al 5% by weight) As a result of refluxing for 1 hour, a light pink transparent solution was obtained. The particle size of the obtained reaction product was measured by a dynamic scattering method, and it was confirmed that the peak top of the particle size distribution was a composite nanoparticle of 1.7 nm. Further, the coordination of Al via oxygen to Er was confirmed by the change in 27Al-NMR spectrum before and after the reaction of tri-s-butoxyaluminum.

  <Preparation of Composite of Inorganic Dispersed Phase and Transparent Organic Polymer> As the transparent organic polymer, a photopolymerizable acrylic resin “Cyclomer” (manufactured by Daicel Chemical Industries) was used. This organic polymer, Er—Al-containing composite nanoparticles prepared by the above method, and a photoradical generator “Irgacure369” (trade name, manufactured by Ciba Geigy Co., Ltd.) are mixed in propylene glycol monomethyl ether ester acetate at room temperature. And stirred for 2 hours to obtain a mixed solution. The mixing ratio was adjusted so that the ratio of erbium in the composite composition was 5.2% and 0.52% by weight based on the total solid content.

  The mixture prepared in this manner is spin-coated on a fused quartz plate using a spinner, and then dried on a plate heater at 90 ° C. for 1 minute to remove residual solvent, and a photopolymerizable acrylic resin is used as a base material. An Er—Al-containing organic-inorganic composite thin film was obtained. Further, this thin film was exposed with an ultrahigh pressure mercury lamp through a photomask in which a linear waveguide pattern having a width of 7 μm was drawn. Subsequently, it was immersed in alkaline water (TMAH 2.3% aqueous solution) for 10 seconds to dissolve and remove a portion that was not exposed with an ultrahigh pressure mercury lamp. Finally, it was dried at 90 ° C. for 2 minutes to obtain an organic-inorganic composite waveguide having a width of 7 μm and a thickness of 2.8 μm composed of a photopolymerizable acrylic resin and an Er—Al inorganic dispersed phase on a quartz substrate.

<Measurement of optical amplification characteristics>
The optical amplification characteristics of the thus obtained organic-inorganic composite waveguide composed of the photopolymerizable acrylic resin and the Er-Al inorganic dispersed phase were measured using an optical system as shown in FIG. A semiconductor laser (6) having a wavelength of 1550 nm and an output of 3 mW was used as the light source for signal light (4), and a pulsed semiconductor laser (7) having a wavelength of 983 nm and a peak output of 150 mW was used as the light source for excitation light (5). In addition, the excitation light (5) is superimposed on the optical axis of the signal light (4) using a dichroic mirror (8) having a high reflectance only in the vicinity of a wavelength of 980 nm, and the rare earth metal-containing organic-inorganic composite produced with both lights It couple | bonded from the end surface of the waveguide (9). Furthermore, in order to measure only the intensity of the signal light (4) after the two lights have propagated through the waveguide, a prism (11) made of SF6 glass is used. The excitation light (5) was separated. Then, only the signal light (4) that passed through the pinhole (12) was received by the light receiver (13), and the light intensity was measured using an oscilloscope.

  As a result, it can be confirmed that the signal intensity when it is lit is amplified with a gain equivalent to 3.8 dB, compared to when the pumping light pulse semiconductor laser is not lit, and functions as an optical amplifier. It was verified that

The present invention is suitably used for an optical amplifier that amplifies signal light intensity 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. In addition, since rare earth metals that can only be doped by about 50 to 100 ppm can be doped by 10% (100,000 ppm) or more, it is possible to reduce the size of an optical amplifier that can only be realized by a long one. For this reason, not only long-distance trunk optical fiber networks that have been used in the past, but also subscriber optical communication networks, where the number of subsequent branches in the transmission path increases and optical transmission loss due to branching becomes a problem. 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.

In the rare earth metal-containing organic-inorganic composite according to the present invention, it is a schematic diagram of a rare earth metal fluorescent material in which another metal species is coordinated to oxygen via a rare earth metal. (A) is a schematic diagram which shows the basic composition of the optical amplifier which is an optical fiber type | mold optical amplifier. FIG. 2B is a schematic diagram showing a basic configuration of an optical amplifier that is an optical waveguide type optical amplifier. It is an optical system diagram which measures an optical amplification characteristic using the optical waveguide type optical amplifier which consists of an Er-Al type organic inorganic composite body produced in Example 1 among the optical amplifiers concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rare earth metal 2 Other metal species coordinated to rare earth metal through oxygen 3 Optical amplifier 4 Signal light 5 Pumping light 6 Semiconductor laser (signal light source)
7 Pulsed semiconductor laser (excitation light source)
8 Dichroic mirror 9 Rare earth metal-containing organic-inorganic composite waveguide 10 Fused silica substrate 11 Prism 12 Pinhole 13 Light receiver

Claims (5)

In an optical amplifier having an optical transmission path for propagating signal light having a specific wavelength or wavelength band and pump light having a wavelength or wavelength band different from the signal light, the signal light intensity is amplified by the pump light. The transmission path is made of an organic polymer in which a rare earth metal is dispersed, and the rare earth metal forms an inorganic dispersed phase in which at least one rare earth metal is coordinated with other metal species via oxygen. An optical amplifier characterized by that. 2. The optical amplifying device according to claim 1, wherein the average diameter of the inorganic dispersed phase obtained by coordinating the rare earth metal and other metal species with oxygen via oxygen is 0.1 to 1000 nm on average. The ratio of the rare earth metal is 90% by weight or less of the total amount of the inorganic dispersed phase obtained by coordinating the organic polymer and the rare earth metal with other metal species via oxygen in terms of solid content. The optical amplifier according to claim 1 or 2. The other metal species coordinated to the rare earth metal through oxygen is one or a combination of two or more elements selected from Group 3B, Group 4A, and Group 5A metals. The optical amplifier according to item. The rare earth metal and an inorganic dispersed phase formed by coordinating other metal species with oxygen via oxygen are formed of a rare earth metal salt and another metal alkoxide. The optical amplifier according to claim 1.