Optical waveguide, optical transmitter and receiver module, and laminated structure

Abstract

An optical waveguide in which a groove is formed on the top surface of a substrate used as a lower clad and a core is formed in the groove, characterized in that the core is formed in such a way that the top face of the core within the groove is at a lower level than the top face of the substrate, and an upper clad may also be provided on the core, and the core is preferably formed from an organic-inorganic hybrid material.

What is claimed is:  
     
         1 . An optical waveguide in which a groove is formed on the top surface of a substrate used as a lower clad and a core is formed in the groove, characterized in that said core is formed in such a way that the top face of said core within said groove is at a lower level than the top face of said substrate.  
     
     
         2 . The optical waveguide according to  claim 1 , characterized in that an upper clad is provided on said core.  
     
     
         3 . The optical waveguide according to  claim 1  or  2 , characterized in that at least one layer of said substrate, said core and said upper clad is formed from an organic-inorganic hybrid material.  
     
     
         4 . An optical waveguide comprising a substrate, a lower clad layer provided on said substrate, and a core layer provided on said lower clad layer, wherein said core layer is formed from an organic-inorganic hybrid material.  
     
     
         5 . The optical waveguide according to  claim 4 , characterized in that said core layer is formed so as to have a thickness of greater than a peripheral thickness.  
     
     
         6 . The optical waveguide according to  claim 4  or  5 , characterized in that an upper clad layer is provided on said core layer.  
     
     
         7 . The optical waveguide according to any one of  claims 3  to  6 , characterized in that said organic-inorganic hybrid material is formed from an organic polymer and metal alkoxide.  
     
     
         8 . The optical waveguide according to  claim 7 , characterized in that two layers contacting with each other among said substrate, said core, said lower clad and said upper clad are formed from organic-inorganic hybrid materials, and one of an organic polymer and metal alkoxide is commonly used in the respective organic-inorganic hybrid materials composing the two layers contacting with each other.  
     
     
         9 . The optical waveguide according to  claim 8 , characterized in that with respect to the organic-inorganic hybrid materials composing said two contacting layers, the organic-inorganic hybrid material composing the upper layer thereof is formed using a raw material and/or a solvent, which does not dissolve the organic-inorganic hybrid material composing the lower layer thereof.  
     
     
         10 . The optical waveguide according to  claim 9 , characterized in that the organic-inorganic hybrid material composing said upper layer is composed of any one material of the material synthesized using alcohol as a solvent and the material synthesized using N-methyl-2-pyrrolidone as a solvent and the organic-inorganic hybrid material composing said lower layer is composed of the other material of the materials synthesized.  
     
     
         11 . The optical waveguide according to  claim 7 , characterized in that one layer of two layers contacting with each other among said substrate, said core, said lower clad and said upper clad is formed from an organic-inorganic hybrid material, and the other layer of the two contacting layers consists of a resin layer containing the same kind of an organic component as an organic component composing the organic-inorganic hybrid material of said one layer, or consists of an inorganic compound containing the metal component of metal alkoxide composing the organic-inorganic hybrid material of said one layer.  
     
     
         12 . The optical waveguide according to any one of  claims 7  to  11 , characterized in that said organic polymer is a polymer having a carbonyl group, a polymer having a benzene ring or a polymer having a naphthalene ring.  
     
     
         13 . The optical waveguide according to  claim 12 , characterized in that said organic polymer is any of polymethyl methacrylate, polystyrene, polyvinyl naphthalene, products of hydrolysis and polycondensation of 3-methacryloxy propyl triethoxysilane, products of hydrolysis and polycondensation of 3-methacryloxy propyl trimethoxysilane, products of hydrolysis and polycondensation of p-styryltriethoxysilane, and products of hydrolysis and polycondensation of p-styryltrimethoxysilane.  
     
     
         14 . The optical waveguide according to any one of  claims 3  to  6 , characterized in that said organic-inorganic hybrid material is formed from at least one kind of metal alkoxide.  
     
     
         15 . The optical waveguide according to any one of claims  3  to  11  and  14 , characterized in that metal alkoxide having a double bond group to be polymerized by light or heat is used as said metal alkoxide.  
     
     
         16 . The optical waveguide according to  claim 14 , characterized in that said organic-inorganic hybrid material is formed from the metal alkoxide having a double bond group to be polymerized by light or heat and from the metal alkoxide not having said double bond group.  
     
     
         17 . The optical waveguide according to  claim 15  or  16 , characterized in that said double bond group is an acryloxy group or a methacryloxy group.  
     
     
         18 . The optical waveguide according to any one of  claims 15  to  17 , characterized in that the metal alkoxide having said double bond group polymerizes through a reaction of the double bond.  
     
     
         19 . The optical waveguide according to  claim 18 , characterized in that said double bond group is an acryloxy group or a methacryloxy group, and the acryloxy group or the methacryloxy group reacts and polymerizes in such a way that the value of (height of the absorption peak resulting from a C═C bond in the neighborhood of 1650 cm- −1 )/(height of the absorption peak resulting from a C═O bond in the neighborhood of 1750 cm −1 ) is 0.1 or less in infrared absorption spectrum.  
     
     
         20 . The optical waveguide according to any one of  claims 14  to  19 , characterized in that two layers contacting with each other among said substrate, said core, said lower clad and said upper clad are formed from organic-inorganic hybrid materials, and at least one kind of metal alkoxide is commonly used in the respective organic-inorganic hybrid materials composing the two contacting layers.  
     
     
         21 . The optical waveguide according to  claim 20 , characterized in that with respect to the organic-inorganic hybrid materials composing said two contacting layers, the organic-inorganic hybrid material composing the upper layer thereof is formed using a raw material and/or a solvent, which does not dissolve the organic-inorganic hybrid material composing the lower layer thereof.  
     
     
         22 . The optical waveguide according to any one of  claims 3  to  6 , characterized in that two layers contacting with each other among said substrate, said core, said lower clad and said upper clad are formed from organic-inorganic hybrid materials, and one layer of the two contacting layers consists of an organic-inorganic hybrid material formed from an organic polymer and metal alkoxide, and the other layer of the two contacting layers consists of an organic-inorganic hybrid material formed from an organic polymer and metal alkoxide or from at least one kind of metal alkoxide.  
     
     
         23 . The optical waveguide according to  claim 22 , characterized in that the organic polymer in said one layer is an acrylic resin and the metal alkoxide in said other layer is metal alkoxide having an acryloxy group or a methacryloxy group.  
     
     
         24 . The optical waveguide according to  claim 23 , characterized in that said metal alkoxide polymerizes through a reaction of the acryloxy group or the methacryloxy group.  
     
     
         25 . The optical waveguide according to  claim 22 , characterized in that the organic polymer in said one layer is a styrene resin and the metal alkoxide in said other layer is metal alkoxide having a benzene ring.  
     
     
         26 . The optical waveguide according to  claim 22 , characterized in that the organic polymer in said one layer is an epoxy resin and the metal alkoxide in said other layer is metal alkoxide having an epoxy group.  
     
     
         27 . The optical waveguide according to any one of  claims 7  to  26 , characterized in that said metal alkoxide is expressed by M(OR) 4 , wherein M is metal and R is an alkyl group; R′M(OR) 3 , wherein M is metal, R is an alkyl group and R′ is an alkyl group, an aryl-containing group, an acryloxy-containing group, a methacryloxy-containing group, a styryl-containing group or an epoxy-containing group; or R′ 2 M(OR) 2 , wherein M is metal, R is an alkyl group and R′ is an alkyl group, an aryl-containing group, an acryloxy-containing group, a methacryloxy-containing group, a styryl-containing group or an epoxy-containing group.  
     
     
         28 . The optical waveguide according to  claim 27 , characterized in that said metal alkoxide is any of tetraethoxysilane, tetramethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, diphenyldiethoxysilane, diphenyldimethoxysilane, 3-methacryloxy propyl triethoxysilane, 3-methacryloxy propyl trimethoxysilane, 3-methacryloxy propyl methyldimethoxysilane, and 3-acryloxy propyl trimethoxysilane.  
     
     
         29 . The optical waveguide according to any one of  claims 7  to  26 , characterized in that said metal alkoxide is expressed by M(OR) n , wherein M is metal, R is an alkyl group and n is 2, 3, 4 or 5; R′M(OR) n-1 , wherein M is metal, R is an alkyl group, R′ is an organic group and n is 2, 3, 4 or 5; or R′ 2 M(OR) n-2 , wherein M is metal, R is an alkyl group, R′ is an organic group and n is 2, 3, 4 or 5.  
     
     
         30 . The optical waveguide according to  claim 29 , characterized in that said organic group is an alkyl group, an aryl-containing group, an acryloxy-containing group, a methacryloxy-containing group, a styryl-containing group, or an epoxy-containing group.  
     
     
         31 . The optical waveguide according to any one of  claims 3  to  30 , characterized in that two layers contacting with each other among said substrate, said core, said lower clad and said upper clad are formed from organic-inorganic hybrid materials, and metal alkoxide having a double bond group to be polymerized by light or heat is used in an upper layer of the two contacting layers, and the metal alkoxide having said double bond group polymerizes through a reaction of said double bond group by light irradiation.  
     
     
         32 . An optical transmitter and receiver module, characterized in that the optical waveguide according to any one of  claims 1  to  31  are used.  
     
     
         33 . A laminated structure formed by laminating organic-inorganic hybrid materials formed from an organic polymer or metal alkoxide, characterized in that either of the organic polymer or the metal alkoxide is commonly used among the different organic-inorganic hybrid materials laminated.  
     
     
         34 . The laminated structure according to  claim 33 , characterized in that with respect to the organic-inorganic hybrid materials composing a laminated structure, the organic-inorganic hybrid material composing the upper layer thereof is formed using a raw material and/or a solvent, which does not dissolve the organic-inorganic hybrid material composing the lower layer thereof.  
     
     
         35 . The laminated structure according to  claim 34 , characterized in that the organic-inorganic hybrid material composing said upper layer is composed of any one material of the material synthesized using alcohol as a solvent and the material synthesized using N-methyl-2-pyrrolidone as a solvent and the organic-inorganic hybrid material composing said lower layer is composed of the other material of the materials synthesized.  
     
     
         36 . The laminated structure according to any one of  claims 33  to  35 , characterized in that said organic polymer is a polymer having a carbonyl group, a polymer having a benzene ring or a polymer having a naphthalene ring.  
     
     
         37 . The laminated structure according to  claim 36 , characterized in that said organic polymer is any of polymethyl methacrylate, polystyrene, polyvinyl naphthalene, products of hydrolysis and polycondensation of 3-methacryloxy propyl triethoxysilane, products of hydrolysis and polycondensation of 3-methacryloxy propyl trimethoxysilane, products of hydrolysis and polycondensation of p-styryltriethoxysilane, and products of hydrolysis and polycondensation of p-styryltrimethoxysilane.  
     
     
         38 . The laminated structure according to any one of  claims 33  to  37 , characterized in that said organic-inorganic hybrid material is prepared by a sol-gel process using an organic polymer, metal alkoxide, and a solvent.  
     
     
         39 . A laminated structure formed by laminating organic-inorganic hybrid materials, characterized in that one layer of the organic-inorganic hybrid material layers is formed from at least one kind of metal alkoxide, and the other layer of the organic-inorganic hybrid material layers is formed from at least one kind of metal alkoxide or from an organic polymer and metal alkoxide, and at least one kind of metal alkoxide is commonly used among the organic-inorganic hybrid materials laminated.  
     
     
         40 . The laminated structure according to any one of  claims 33  to  35  and  39 , characterized in that metal alkoxide having a double bond group to be polymerized by light or heat is used as said metal alkoxide.  
     
     
         41 . The laminated structure according to  claim 39 , characterized in that the organic-inorganic hybrid material of said one layer and/or the organic-inorganic hybrid material of said other layer is formed from the metal alkoxide having a double bond group to be polymerized by light or heat and from the metal alkoxide not having said double bond group.  
     
     
         42 . The laminated structure according to  claim 40  or  41 , characterized in that said double bond group is an acryloxy group or a methacryloxy group.  
     
     
         43 . The laminated structure according to any one of  claims 40  to  42 , characterized in that the metal alkoxide having said double bond group polymerizes through a reaction of the double bond.  
     
     
         44 . The laminated structure according to  claim 43 , characterized in that said double bond group is an acryloxy group or a methacryloxy group, and the acryloxy group or the methacryloxy group reacts and polymerizes in such a way that the value of (height of the absorption peak resulting from a C═C bond in the neighborhood of 1650 cm −1 )/(height of the absorption peak resulting from a C═O bond in the neighborhood of 1750 cm −1 ) is 0.1 or less in infrared absorption spectrum.  
     
     
         45 . A laminated structure formed by laminating organic-inorganic hybrid materials, characterized in that one layer of the organic-inorganic hybrid material layers is formed from an organic polymer and metal alkoxide, and the other layer of the organic-inorganic hybrid material layers is formed from an organic polymer and metal alkoxide or from at least one kind of metal alkoxide.  
     
     
         46 . The laminated structure according to  claim 45 , characterized in that the organic polymer in said one layer is an acrylic resin and the metal alkoxide in said other layer is metal alkoxide having an acryloxy group or a methacryloxy group.  
     
     
         47 . The laminated structure according to  claim 46 , characterized in that said metal alkoxide polymerizes through a reaction of the acryloxy group or the methacryloxy group.  
     
     
         48 . The laminated structure according to  claim 45 , characterized in that the organic polymer in said one layer is a styrene resin and the metal alkoxide in said other layer is metal alkoxide having a benzene ring.  
     
     
         49 . The laminated structure according to  claim 45 , characterized in that the organic polymer in said one layer is an epoxy resin and the metal alkoxide in said other layer is metal alkoxide having an epoxy group.  
     
     
         50 . The laminated structure according to any one of  claims 33  to  49 , characterized in that said metal alkoxide is expressed by M(OR) 4 , wherein M is metal and R is an alkyl group; R′M(OR) 3 , wherein M is metal, R is an alkyl group and R′ is an alkyl group, an aryl-containing group, an acryloxy-containing group, a methacryloxy-containing group, a styryl-containing group or an epoxy-containing group; or R′ 2 M(OR) 2 , wherein M is metal, R is an alkyl group and R′ is an alkyl group, an aryl-containing group, an acryloxy-containing group, a methacryloxy-containing group, a styryl-containing group or an epoxy-containing group.  
     
     
         51 . The laminated structure according to  claim 50 , characterized in that said metal alkoxide is any of tetraethoxysilane, tetramethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, diphenyldiethoxysilane, diphenyldimethoxysilane, 3-methacryloxy propyl triethoxysilane, 3-methacryloxy propyl trimethoxysilane, 3-methacryloxy propyl methyldimethoxysilane, and 3-acryloxy propyl trimethoxysilane.  
     
     
         52 . The laminated structure according to any one of  claims 33  to  49 , characterized in that said metal alkoxide is expressed by M(OR) n , wherein M is metal, R is an alkyl group and n is 2, 3, 4 or 5; R′M(OR) n-1 , wherein M is metal, R is an alkyl group, R′ is an organic group and n is 2, 3, 4 or 5; or R′ 2 M(OR) n-2 , wherein M is metal, R is an alkyl group, R′ is an organic group and n is 2, 3, 4 or 5.  
     
     
         53 . The laminated structure according to  claim 52 , characterized in that said organic group is an alkyl group, an aryl-containing group, an acryloxy-containing group, a methacryloxy-containing group, a styryl-containing group, or an epoxy-containing group.  
     
     
         54 . The laminated structure according to any one of  claims 39  to  53 , characterized in that said organic-inorganic hybrid material is prepared by a sol-gel process using an organic polymer metal alkoxide, and a solvent or by a sol-gel process using at least one kind of metal alkoxide and a solvent.  
     
     
         55 . The laminated structure according to any one of  claims 33  to  54 , characterized in that said laminated structure is formed by laminating organic-inorganic hybrid materials, and a metal alkoxide having a double bond group to be polymerized by light or heat is used in an upper layer of said laminated structure, and the metal alkoxide having said double bond group polymerizes through a reaction of said double bond group by light irradiation.