MXPA99005482A - Hybrid organic-inorganic planar optical waveguide device - Google Patents

Abstract

A planar optical device is formed on a substrate (12) and comprising an array of waveguide cores (14) and a cladding layer (16) formed contiguously with the cores. At least one of the array of waveguide cores (14) and the cladding layer (16) is an inorganic-organic hybrid material that comprises an extended matrix containing silicon and oxygen atoms with at least a fraction of the silicon being directly bonded to substituted or unsubstituted hydrocarbon atoms. In accordance with other embodiments of the invention, a method of forming an array of cores comprises the steps of preparing a core composition precursor material;partially hydrolyzing and polymerizing the material;forming an array of waveguide cores under conditions effective to form an inorganic-organic hybrid material that comprises an extended matrix containing silicon and oxygen atoms with at least a fraction of the silicon being directly bonded to substituted or unsubstituted hydrocarbon atoms.

Description

ORGANIC-INORGANIC FLAT AND ORIENTAL HYBRID OPTICAL GUIDE DEVICE RELATED REQUESTS This application claims the benefit of the US patent application. Serial No. 60 / 032,961 filed December 13, 1996, entitled "METHODS AND COMPOSITIONS FOR CONNECTING OPTICALLY TRANSMISSIVE MATERIALS" by S. Dawes, which is incorporated by reference, and the patent application of E.U. Serial No. 08 / 956,177 filed on October 22, 1997, entitled "OPTICALLY TRANSMISSIVE MATERIAL AND BOND" by S. Dawes and A. Sadd, which is incorporated by reference.

FIELD OF THE INVENTION The present invention relates to a planar optical waveguide device in which one of the layers is formed according to a method of processing inorganic-organic hybrid material. In particular, one of the layers is an inorganic-organic hybrid material comprising an extended matrix containing and silicon and oxygen atoms in which a fraction of the silicon atoms are directly bound to substituted or unsubstituted hydrocarbon portions. The present invention also relates to a method for forming a flat optical waveguide device without the use of a lithographic process. Preferably, the inorganic-organic material comprises a solid material comprising methyl-siloxane groups, phenyl-siloxane and fluorine groups, which is provided by thermally curing a precursor mixture comprising polydimethylsiloxane, methyltrialkoxysilane, phenyltrialkoxysilane and a structural modifier including a fluorine atom.

BACKGROUND OF THE INVENTION A typical flat optical waveguide device includes a flat substrate, an array of waveguide centers on the flat substrate and a coating layer. Optical radiation propagates in the centers. The lower index coating layer confines the radiation to the higher index centers. In some cases, there is a second coating layer between the centers and the flat substrate. The flat optical waveguide device is designed to transport optical radiation through a two-dimensional flat substrate surface. The device usually performs a passive function in the optical radiation in order to modify the output signal of the input signal in a particular way. Some examples of flat optical waveguide devices are as described below. Optical separators divide the energy of the optical signal into a waveguide in two or more waveguides. Couplers add the optical signal from two or more waveguides to create a smaller number of output waveguides. Spectral filters, polarizers and insulators can be incorporated into the waveguide design. WDM structures (Wavelength Division Multiplexing) separate an optical input signal into spectrally discrete output waveguides, usually using either phase layout designs or grids. A particular advantage of flat optical waveguide devices is the ability to include multiple functions in a platform. Active functionality can also be included in flat designs, where the input signal is altered by the interaction with a second optical or electrical signal. Examples of active functions include switching (with electro-optical, thermo-optical or acousto-optical devices) and amplification. In general, the key attributes for flat waveguide guidance devices are optical loss and processing capacity and cost. Processing capacity means the ability to write desired patterns of waveguide structures with good resolution and without fissures. Each device has its own specifications, which have to be fulfilled in addition to the more generic requirements. To achieve flat optical waveguides, the state of the art typically employs the following general procedures. First, a substrate is provided. The substrate is either silicon or silica, and is provided as a clean smooth flat surface. In the case of a silicon substrate, a liner coating (a silica or low index silica) is deposited. Then, a central layer of high index (a silica gel) is deposited on the substrate, with a precise thickness. The central layer and liner coatings are made by a flame hydrolysis technique, or a CVD technique or a plasma deposition technique. Next, a pattern is given to the central layer to form an array of waveguide centers usually by some variation of a lithography / etch procedure. Finally, a layer of low index coating is deposited to complete the waveguide structure. All variations in these processing steps share a high intrinsic cost. Deposition times are long and pattern forming technologies are problematic. The procedure is capable of forming high quality structures, with characteristic resolution as low as 0.5 microns and low defect counts. In applications of high added value such as WDM devices, the procedure has shown some commercial possibility. However, in other applications such as couplers, the costs are too high to compete with other technologies. In view of the above, an object of the invention is to provide a flat optical waveguide device that overcomes the problems of the prior art. More specifically, an object of the invention is to provide a flat optical waveguide device which is formed of a low cost optical material with low absorbency, which has a scale of refractive indexes and which can be deposited rapidly, a large occurrence occurring. part of mass loss in the non-solid state. It is also an object of the invention to provide a method for forming a flat waveguide device that obviates the need for lithographic techniques.

BRIEF DESCRIPTION OF THE INVENTION According to an illustrative embodiment of the invention, a flat optical device is formed on a substrate. The device comprises an arrangement of waveguide centers guiding optical radiation. A coating layer is contiguously formed with the arrangement of waveguide centers to confine the optical radiation to the array of waveguide centers. At least one of the arrangement of waveguide centers and coating layer is an inorganic-organic hybrid material comprising an extended matrix containing silicon and oxygen atoms with at least a fraction of the silicon atoms being directly bonded to substituted or unsubstituted hydrocarbon portions. This material can be designed with a refractive index between 1.4 and 1.55 and can be quickly deposited at thicknesses of up to 40 microns. The material is especially suitable for forming flat waveguide structures thanks to its low optical loss to transmission windows of 1310 nm and 1550 nm. The material is thermally cured from a viscous and solvent-free state to achieve complete condensation and conclude the elastic properties with a minimum mass loss, developing resistance to cracking and retention in an appropriate manner. According to another embodiment of the invention, a method for forming a flat optical device obviates the need for a lithographic process. Illustratively, a method for forming an array arrangement comprises the following steps: (1) preparing a core waveguide composition precursor material comprising at least one silane and a hydrocarbon portion source, (2) hydrolyzing and polymerizing partially the central waveguide precursor material to form a central waveguide composition, (3) using a mold, forming an array of waveguide centers comprising the central waveguide composition and (4) completing the hydrolysis and polymerization of the central waveguide composition under effective comp conditions to form an inorganic-organic hybrid material comprising an extended matrix containing silicon and oxygen atoms with at least a fraction of the silicon atoms being directly bound to hydrocarbon portions substituted or unsubstituted. A coating layer is then deposited on the arrangement of waveguide centers. The use of the mold to form a pattern in the arrangement of waveguide centers obviates the need for a lithographic process. This is a very significant advantage of the invention.

In combination, a complete planar waveguide structure can be made, or if desired, an overcoat layer can be provided on a conventional etched central silica sapphire waveguide arrangement. The main advantage that can be achieved from this invention is the cost. The use of the overcoat of the invention in glass wave guide arrangements with conventionally formed patterns can provide advantages. The low processing temperature used avoids any deformation of the waveguide centers, while processing at high temperatures can distort the original shape of the waveguide. The low temperature and low modulus of the overcoating of the invention also results in low voltage fields on the waveguides, whereby the voltage induced polarization effects can be minimized.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates schematically a flat waveguide device according to the invention. Figure 2 schematically illustrates an alternative flat waveguide device according to the invention. Figures 3A, 3B, 3C, 3D, 3E, 3F, 3G, 3H and 31 schematically illustrate preferred methods for creating an array of waveguide centers according to the invention.

Figures 4A, 4B, 4C, 4D and 4E illustrate schematically another preferred method for creating an array of waveguide centers according to the invention. Figures 5, 6 and 7 are quasi-infrared absorbance spectra of hybrid soi-gel materials.

DETAILED DESCRIPTION OF THE INVENTION For reasons of clarity, the detailed description of the invention is divided into the following subsections: A. Flat optical waveguide device B. Materials used to form the flat optical waveguide device C. Specific example of materials used to form the plane optical waveguide device D. Method for forming the piano optical waveguide device E. Examples of flat optical waveguide devices F. Spectra of materials used to form flat waveguide devices A. flat optical waveguide In figure 1 a flat optical waveguide device according to an illustrative embodiment of the invention is shown in cross section. The device 10 comprises a substrate 12. The substrate 12 can be silicon or silica. An arrangement with central waveguide pattern 14 is formed on the substrate. Illustratively, the dimension of each waveguide center (height and width) can be as small as 0.5 microns. The waveguide centers 14 can be given a pattern to form separators, couplers, filters, WDM devices and devices with other functions as well. The waveguide centers 14 are covered with coating layer 16. In one embodiment of the invention, the arrangement of waveguide centers is a central silicate waveguide arrangement conventionally recorded. The coating layer can be an inorganic-organic hybrid material comprising an extended matrix containing oxygen and silicon atoms in which a fraction of the silicon atoms is directly bonded to substituted or unsubstituted hydrocarbon portions. In an alternative embodiment of the invention, both the arrangement of centers 14 and the coating layer 16 can be an inorganic-organic hybrid material comprising an extended matrix containing silicon and oxygen atoms in which a fraction of the silicon atoms is directly linked to substituted or unsubstituted hydrocarbon portions. As explained below, the refractive index of this material can be designed to provide high index centers and a low index coating layer. In an alternative embodiment of the invention, shown in Figure 2, a piano optical device 20 comprises a substrate 22, a first coating layer 24, an array of waveguide centers 26 and a second coating layer 28. The layers of coating 24, 28 and the arrangement of waveguide centers may all comprise an inorganic-organic hybrid material comprising an extended matrix containing silicon and oxygen atoms in which a fraction of the silicon atoms is directly attached to portions of substituted or unsubstituted hydrocarbons, the refractive index being chosen for each individual layer. Preferably, the inorganic-organic material comprises a solid material consisting of methyl-siloxane groups, phenyl-siloxane and fluorine groups, which is provided by curing, most preferably heat curing, and a precursor material. Preferably, the precursor material comprises a precursor mixture consisting of polydimethylsiloxane, methyltrialkoxysilane, phenyltrialkoxysilane and a structural modifier with a fluorine atom.

B. Materials used to form the flat optical waveguide device The practice of the invention further includes the preparation of a coating layer and / or a core layer composition precursor material. As shown in detail below, the precursor material is adjusted depending on whether a precursor material of core composition or coating composition is desired. The coating and core compositions are formed from the precursor material of central composition or coating, respectively. These compositions are then used to form coating layers and arrangements of waveguide centers. The precursor material comprises a mixture of hydrolysable precursors composed essentially of at least one alkoxysilane selected from the group consisting of tetraalkoxysilanes, alkyltrialkoxysilanes and aryltrialcoxysilanes. Optionally, it contains modifiers such as those described below. The mixture can be dissolved in a solvent such as an alcohol and hydrolyzed by the addition of acid and water. Alternatively, the precursor mixture can be mixed pure (without solvents) and hydrolyzed by the addition of water and optionally acid. The composition is aged while hydrolysis and condensation (polymerization) proceed to form a viscous core coating composition. This partially hydrolyzed and polymerized material is hereinafter referred to as the core or coating composition for contrasting with the center or final coating, in which the hydrolysis and polymerization are essentially complete after curing. It is desirable to conduct the hydrolysis and condensation reactions to a sufficient degree so that no precursor is lost during the evaporation of the solvent. Studies have shown that sufficient aging at room temperature is required for this purpose in the order of 50 hours. It has been found that mild warming of the mixture below 100 ° C can shorten the time to less than 5 hours. In particular, a comparable degree of polymerization (approximately 80%) was achieved by heating to about 75 ° C for three hours. Surprisingly, it was found that the gels produced by the accelerated aging process were less prone to cracking at high heating rates to form the final coating or core layer. Tetraalkoxysilanes are silicon atoms having four alkoxy groups attached thereto. The four alkoxy groups are usually the same, but this is only for convenience. Alkoxy, as used herein, includes the deprotonated form of any alcohol, including aliphatic alcohols. Alkyltrialkoxysilanes are silicon atoms having three alkoxy groups and an alkyl group attached thereto. Alkyl also includes arylalkyl. Suitable alkyltrialkoxysilanes for use in the practice of the present invention include, for example, methytrimethoxysilane ("MTMS") and methyltriethoxysilane ("MTES"). Aryltrialkoxysilanes are silicon atoms having three alkoxy groups and an aryl group attached thereto. As used herein, aryl also includes alkylaryl moieties. Suitable aryltrialkoxysilanes for use in the practice of the present invention include, for example, phenyltrimethoxysilane ("PTMS") and phenyltriethoxysilane ("PTES"). Preferably, the precursor mixture comprises PDMS (polydimethylsiloxane), MTES and PTES, and preferably further comprises a source of fluorine such as HF and trifluorosilane, and water. The central or hydrolyzed coating composition may advantageously include other organic components which, at a microscopic level, modify the inorganic network formed by the polymerization of the silane hydrolysis products. The organic component can modify the network with an organo-metallic bond to a silicon atom. Alternatively, the organic component can coexist as an interpenetrating, intermolecular or intramolecular network within the inorganic network that does not bind to a silicon atom. Suitable organic components that can be incorporated into the hydrolyzed link composition include one or more hydrolysis products of inert network modifiers, active network modifiers, organic network forming modifiers, reactive polymer modifiers, reactive polymerizable modifiers and interpenetrating network modifiers. not interactive Inert network modifiers include alkylalkoxysilanes and arylalkoxysilanes, particularly those having the formula (R1) n (R2O) 4. nS, where n is 1, 2 or 3. OR 2 is an alkoxy moiety, such as ethoxy and methoxy.

R may be an alkyl portion or an aryl portion, including, for example, methyl, ethyl and phenyl. The central or hydrolyzed coating composition may include from about 0 to about 100 mole%, preferably about 50 to about 100 mole%, more preferably about 50 to about 96 mole% of the hydrolysis product of the inert network modifier, such as the hydrolysis product of methyltriethoxysilane. Additional details regarding the inert network modifiers can be found in the literature. Active network modifiers are alkoxysilanes (substituted with alkyl) and alkoxysilanes (substituted with aryl) wherein at least one of the alkyl or aryl substituents is a functional group capable of forming complexes with metal atoms or ions, such as a group functional amino, a mercapto functional group or a hydroxyl functional group. It is believed that the functional group promotes the adhesion of the surface of the central composition or polymerized coating to inorganic materials. Active network modifiers can also promote adhesion to organic surfaces.

Suitable active network modifiers are those having the formula (R3) n (R2O) 4.nS, where n is 1, 2 or 3 and wherein OR2 is an alkoxy moiety. R3 may be an alkyl or aryl portion substituted with amine, carboxy, mercapto or hydroxy. The hydrolysis product of the active network modifier is preferably present in an amount of about 1 to about 25 mol%. As indicated above, the hydroxylated coating center composition may also include one or more hydrolysis products or organic network forming modifiers, reactive polymer modifiers or reactive polymerizable modifiers. It is believed that the hydrolysis products of these modifiers, when polymerized, form organic networks that are covalently linked to the inorganic network by means of Si-C bonds. The organic network-forming modifiers are alkoxysilane (alkyl-substituted) compounds which are substituted with groups capable of participating in polymerization reactions with other alkoxysilane (aikilo-substituted) compounds substituted in the same manner. Suitable organic network forming modifiers include those having the formula (R4) n (R2O) 4_nSi, wherein n is 1, 2 or 3 and OR2 is an alkoxy portion, suitable examples of which are ethoxy and methoxy. R may be an alkyl portion or substituted aryl portion, such as an alkoxyloxyalkyl-, an acryloxyalkyl-, a vinyl or an alkylsilane (epoxy-substituted).

The central or hydrolyzed coating composition may include from about 0 to about 95 mole%, preferably about 0 to about 50 mole% of a hydrolysis product of an organic network forming modifier, such as the methacryloxypropyltriethoxysilane hydrolysis product. When used to impart a functional character, such as curing, the hydrolysis products of the organic network forming modifiers are preferably present in an amount of about 20 to about 50 mol%. When using organic network forming modifiers, it may be particularly advantageous to include a photoinitiator in the central or hydrolyzed coating composition. Suitable photoinitiators include titanocene radical photoinitiators, such as IRGACURE ™ 784 or cationic ferrocinium photoinitiators, such as IRGACURE ™ 261 (both available from Ciba Geigy, Ardsley, NY). Photoinitiators, when employed, are preferably included in the central or hydrolyzed coating composition in amounts of less than about 0.8 weight percent, preferably about 0.2 to about 0.8 weight percent. Reactive polymer modifiers are organic or inorganic polymers that are capable of participating in tetraalkoxysilane condensation reactions, hydrolyzed alkyltrialkoxysilanes or aryltrialkyoxysilanes. Suitable reactive polymer modifiers include those having the formula (R 2 O) 3 O-Si-O- (P) n-Si-O (OR 2) 3 or (HO) - (P) n-OH, wherein (P) n represents an organic polymer, such as polytetramethylene oxide, and OR2 is an alkoxy moiety, such as ethoxy and methoxy. Other suitable reactive polymeric modifiers include polydialkylsiloxanes having the formula R50- [Si (R6) 2-0] nR5, wherein, n is an integer from about 2 to about 50, R5 is a hydrogen or an alkyl or aryl portion, R6 is an alkyl group, preferably a methyl group. Preferably, the reactive polymer modifier is a polydimethylsiloxane having a molecular weight of about 200 to about 900 g / mol, preferably about 550 g / mol. The central or hydrolyzed coating composition may include from about 0 to about 40 mol%, preferably about 4 to about 8 mol%, of the hydrolysis product of a reactive polymer modifier. Reactive polymerizable modifiers are substituted alkylalkoxysilane compounds that can form organic networks only in combination with a second polymerizable component that is reactive with the substituent on the substituted alkylalkoxysilane compound. The second polymerizable component may or may not be attached to an alkoxysilane. Reactive polymerizable modifiers include (aminoalkyl) alkoxysilanes, (aminoaryl) alkoxysilanes, (epoxy-substituted alkyl) alkoxysilanes, (substituted epoxy aryl) alkoxysilanes and combinations thereof. In cases where the reactive polymerizable modifier is an (aminoalkyl) alkoxysilane or an (aminoaryl) alkoxysilane, the central or hydrolyzed coating composition may further include a hydrolysis product of a (substituted epoxy alkyl) alkoxysilane. Alternatively or additionally, the central or hydrolyzed coating composition may further include an organic component having two or more functional groups reactive with epoxy groups, such as amine groups, connected by an organic base structure. Suitable base structures include alkylene and diradical portions of polymers. In cases where the reactive polymerizable modifier contains an (aminoalkyl) alkoxysilane, the hydrolyzed linkage composition may further include an organic component having two or more functional groups that are reactive with amines, forming covalent bonds therewith. The central or hydrolyzed coating composition may include from about 0 to about 95 mol%, preferably from about 0 to about 50 mol% of the hydrolysis product of the reactive polymerizable modifier. When used to impart a functional character, such as to enable photo curing or increase the plasticity of the extended silicon oxide matrix, the hydrolysis product of the reactive polymerizable modifier is preferably present in an amount of about 20 to about 50 mol% . In a preferred embodiment, at least one of these reactive polymerizable modifiers contains a hydrolytically stable silicon-carbon bond.

Non-interactive interpenetrating network modifiers are organic polymers, preferably organic polymers, which do not contain groups capable of forming Si-C bonds with silicon atoms, or precursors for such organic polymers that are capable of forming said organic polymers by, for example, radical polymerization. These non-interactive interpenetrating network modifiers can be incorporated into the central or hydrolyzed coating composition in amounts of about 0 to about 50 mol%. When used to impart a functional character, such as to increase the plasticity or to introduce photoactive polymers in the extended silicon-oxide matrix, the non-interactive penetrating network modifiers are preferably present in an amount of about 5 to about 25% molar. Further details regarding these non-interactive interpenetrating network modifiers can be found, for example, in the US patent. No. 5,412,016 to Sharp, which is incorporated herein by reference. When increased refractive indices of the centralized or hydrolyzed and polymerized coating composition are desired, the composition may further include one or more reactive compounds containing an element selected from the group consisting of Ge, Ti, Zr, Hf, Er and Nd. Optionally, the alkoxides can be hydrolyzed to their hydrolysis products.

The amount of alkoxide and the hydrolysis products thereof collectively present in the central or hydrolyzed coating composition depends on the desired refractive index after the polymerization. Suitable amounts of alkoxide and hydrolysis products thereof collectively present in the central or hydrolyzed coating composition range from about 0 to about 25 mol%, preferably from about 0 to about 15 mol%, depending on the desired change in the refractive index and stability of the central composition or hydrolysed coating. The refractive index of the central composition or hydrolyzed coating is preferably varied by incorporating aryltrialkoxysilanes (particularly phenytriperkoxysilanes) and / or aryltrifluorosilanes (particularly phenyltrifluorosilanes) in the hydrolyzed binding composition. The central or hydrolyzed coating composition preferably contains a fluoride source, such as a hydrolysis product of a fluorosilane, examples of which include alkyl fluorosilanes. Other suitable fluoride sources, such as hydrogen fluoride, ammonium bifluoride and other dissociating fluoride salts can be used. The incorporation of a fluoride source is advantageous when the suppression of the infrared absorption band of SiO-H of ca. 3300 cm "1. Such a case is when the optically transmitting materials must pass infrared radiation without significant attenuation.

The amount of fluoride source present in the central or hydrolyzed coating composition depends mainly on the acceptable level of infrared absorption. When the fluoride source is the hydrolysis product of a fluorosilane, a significant reduction of the Si-OH absorption band can be achieved when the amount of the hydrolysis product of the fluororesilane varies from about 0 to about 25%, preferably about 5. to approximately 15 mol%. Hydrolyzed core or coating compositions which are particularly preferred for use in the practice of the present invention are polymerizable inorganic-organic hybrids which include a silane selected from the group consisting of a tetraalkoxysilane, an alkyltrialkoxysilane, an aryltrialkoxysilane, a trialkoxysilane, an alkoxypropyltrialkoxysilane and combinations thereof, in a total amount of about 50 to about 95 mole%. The polymerizable composition of the invention also includes a network modifier selected from the group consisting of a monomeric dialkydialkoxysilane and a polymeric polydialkylsilane in an amount of about 4 to about 25 mol%, an aryltrifluorosilane in an amount of about 5 to about 20 mol%, a tetraalkoxytitanium in an amount of about 0 to about 10 mol%, and a tetraalkoxygermanium in an amount of about 0 to about 20 mol%, of the sol-gel composition.

The hydrolyzed core or coating compositions can be prepared by adding water to the core layer or coating precursor materials containing an alkoxysilane. The hydrolysis begins immediately after the addition of water, and results in the replacement of the alkoxy groups with hydroxy groups. The hydrolysis rates of the different silanes may differ, depending on the nature of the constituents attached to the silicon atoms. Therefore, it may be advantageous to start the process of hydrolysis of several alkoxysilanes (or alkoxides of other elements, such as tetraethoxygermanium) separately and to mix them after some or all of the alkoxy groups have been hydrolyzed. The amount of water used to carry out the hydrolysis phase of the curing process can vary widely, such as from about 25% to about 800% the stoichiometric amount required to fully hydrolyse all alkoxy-silicon bonds present in the precursor materials in base to the reaction 2? SOROR + H2O? YES-O-YES? + ROH. Preferably, the amount of water added is from about 75% to about 100% the stoichiometric amount. As little as 25% of the stoichiometric amount can be added and / or water can be added to the gel in stages. The hydrolysis reactions of the alkoxides release alcohol as a reaction product. The alcohols are removed from the hydrolyzed central or coating compositions by opening the container to the air and evaporating. The central or hydrolyzed coating composition becomes increasingly viscous as the alcohol is removed. The hydrolysis can be carried out using the following general procedure. A core or coating material, including a selected alkoxysilane, together with one or more of the optional additive modifiers, is dissolved in a suitable solvent. Preferably, the solvent is not reactive with, and is capable of, solubilizing the entire precursor composition. The preferred solvent is ethanoi. When the reaction rates of the precursors are sufficiently similar, the precursor composition can be mixed and hydrolyzed directly, without a solvent. Water and acid are added to the solution of the precursor composition, preferably at reflux. Water and acid are first mixed in a solvent, which may be the same solvent used to dissolve the precursor composition. The acid and water can be added at the same time, slowly, either by dripping or in several aliquots. The addition is carried out over the course of 20 minutes to 8 hours, preferably 1 to 3 hours, preferably while maintaining the reaction mixture at reflux and with stirring. After the addition is complete, the reaction mixture may be stirred at reflux for an additional period, preferably about 30 minutes. In order to accurately control the amount of water introduced into the reaction mixture, the optional addition and subsequent agitation and reflux can be carried out in an inert atmosphere, such as nitrogen or argon. When the reactions are conducted without added solvent, the water is added in one or two aliquots, and mixed vigorously at temperatures of about 50 to about 90 ° C, until they are homogeneous. The hydrolyzed central or coating compositions containing mainly alkyltrialkoxides can be advantageously prepared by the following alternative general method. A precursor material of central composition or coating, including a selected alkoxysilane, together with one or more of the optional modifiers, is prepared without the addition of solvent. Water is added in the desired amount to the precursor material of the composition. The addition of water can be carried out at room temperature, or the composition can be heated, such as in a hot water bath. Preferably, the precursor material of the central or coating composition, before the addition of water, is at a temperature of about 60 ° C to about 80 ° C. Alternatively, the water can be added at a reduced temperature to improve the homogeneity via slow hydrolysis. The amount of water with which the precursor material reacts is better controlled if the addition is conducted under conditions that exclude moisture in the ambient air, such as by plugging the reaction vessel. The addition of water to the precursor material often produces a separate phase mixture. Under these circumstances, the phase separated mixture can be stirred to dissolve the water in the precursor material. The stirring is preferably carried out in a container isolated from the ambient atmosphere, such as with a lid. After agitation, the system is preferably vented (if it is capped) and then settled, preferably isolated from the ambient atmosphere, at a temperature from room temperature to about 100 ° C for a period of about 15 minutes to about 1 hour. After cooling, the central or hydrolyzed coating composition may, optionally, be aged, preferably at room temperature and for about 1 to about 10 days. Both germanium and titanium alkoxides are rapidly hydrolyzed. It is desirable, therefore, to delay their addition to the parent material until the alkoxysilanes are at least partially hydrolyzed. The delay incorporates germanium and titanium more evenly into the inorganic matrix. The hydrolysis reaction can be catalyzed by a mineral acid or an organic acid, preferably HCl. The amount of acid used in the hydration reaction may be from about 0 to about 5%, expressed in terms of acid equivalents per mole of water used. When the precursor material contains a source of fluoride, such as PTFS, the use of the acid provides very few advantages. The amount of water used in the hydrolysis reaction can be from about 10% to about 200%, expressed in terms of moles of water per moles of hydrolyzable alkoxy group. The stoichiometric hydrolysis of one mole of alkoxy group requires 0.5 mole of water. In cases where a polydialkylsiloxane is contained in the precursor material, the amount of water is preferably about 45% to about 55%. After addition of the acid and water and optional additional reflux, the resulting hydrolyzed core or coating composition can be stored at room temperature for about 3 to about 30 days before being used in the connection of optically transmitting components. The shelf life can often be extended by using dimethylformamide as the reaction solvent, or as a co-solvent with an alcohol. In cases where the central or hydrolyzed coating composition contains germanium or titanium, its shelf life can be extended by adding germanium or titanium alkoxide to the sol after the hydrolysis of the akoxysilanes is partial, or preferably, fully completed. Countertop life may also be extended by reducing the amount of water employed in the hydrolysis process, such as from about 50% to about 25% of the stoichiometric amount. The central or hydrolyzed coating composition is applied to a substrate to form a layer. As described in detail below, a pattern can be formed in the layer using a mold. The central or coating composition is then polymerized to form the flat waveguide device. It is often beneficial to allow the by-product reaction alcohols to evaporate from the core or coating composition prior to the polymeric action. Polymerization, as used in this context, refers to the polymerization of the inorganic component of the central composition or hydrolyzed coating. The polymerization can be carried out at room temperature for a prolonged period. Nevertheless, it is usually desirable to accelerate the polymerization process, such as by the application of thermal radiation. Heat can be applied from any conventional thermal radiation source, such as a flame, a heat gun, a high temperature oil bath, or radiation, such as with a focused infrared laser. The amount of heat applied is preferably sufficient to rapidly polymerize the central or hydrolyzed coating composition but without causing significant entrapment of the solvent as bubbles. The temperature for the polymerizations is from about 150 ° C to about 300 ° C, preferably 225 ° C to about 250 ° C. The polymerized composition is strong enough to withstand normal handling. In some cases, the optical and thermal properties of the central composition or polymerized coating can be improved by condensing the central composition or polymerized coating. Preferably, the polymerized binding composition is exposed to a temperature higher than that used to carry out the polymerization.

After polymerization, the center or coating formed depends after the components of the central composition or initial coating. The compositions, which contain hydrolysis products of one or more modifiers, form central or coating layers that contain a silicon-oxide matrix (ie, Si-O-Si network), in which a portion of the silicon are directly bound to substituted or unsubstituted hydrocarbon portions. When the central or coating composition contains a hydrolysis product of an inert network modifier or a polydialkylsiloxane, the hydrocarbon portions are unsubstituted alkyl or aryl portions. When the central or coating composition contains a hydrolysis product of an active network modifier, the hydrocarbon portions are substituted alkyl or aryl portions. When the core or coating composition contains a hydrolysis product of an organic network forming modifier, the hydrolyzed portions are substituted alkyl or aryl portions, such as alkylene or arylene portions. The alkylene or arylene portions are attached at each end to silicon atoms of the extended silicon-oxide matrix. This forms Si-R-R'-R-Si bonds, where R is an alkylene portion and R 'represents the radical polymerization product of the polymerizable organic functional groups contained in the modifier. When the central or hydrolyzed coating composition contains a hydrolysis product of a reactive polymerizable modifier that is not a polydialkylisiloxane, the hydrocarbon moieties are substituted alkyl or aryl moieties, such as those containing alkylene or arylene portions having the formula -R -. The alkylene or arylene portions are attached at each end of silicon atoms to form Si-R-Si bonds, wherein, R represents an organic polymer dirradicai. When the hydrolyzed central or coating composition contains a hydrolysis product of a reactive polymerizable modifier, the hydrocarbon moieties are substituted alkyl or aryl moieties, such as those containing alkylene or arylene portions having the formula -R-R'-R . The alkylene or arylene portions are attached at each end of silicon atoms to form Si-R-R'-R Si bonds, wherein R is an alkylene portion and R 'contains a portion produced by a reaction of an amine with a group reactive functional with amine. The fraction of silicon atoms directly attached to substituted or unsubstituted alkyl portions can be from about 4% to about 100%, preferably from about 20% to about 100%, more preferably from about 50% to about 100%. Hydrolyzed core or coating compositions containing non-interacting, interpenetrating network modifiers or their hydrolysis products form bonding materials that contain an extended silicon-oxide matrix (ie, a Si-O-Si network) and a matrix interpenetrating organic polymer. The extended silicon-oxide matrix and the interpenetrating organic polymer matrix are not joined together, so that substantially one of the atoms in the interpenetrating organic polymer matrix are atoms bound in the extended silicon-oxide matrix. A common problem with sol-gel processed materials is the structural damage incurred during polymerization and curing as a result of loss of mass and condensation. The central and coating compositions have unique visco-elastic properties during the polymerization and curing processes that make it possible to avoid a severe accumulation of tension. In a preferred embodiment, the central or hydrolyzed coating composition can be air dried to remove alcohol reaction byproducts, and any solvent used in the hydrolysis step. Drying produces a viscous clear fluid whose mass is between 40% and 50% the original mass of the sample of the central composition or hydrolysed coating. The central or hydrolyzed and dried coating composition can be heated to temperatures as high as 100 ° C with additional mass loss of 2 to 5% of the core or original hydrolyzed coating sample. The reheated material maintains the ability to be plastically deformed without permanent damage. The central composition or dry coating can be cured at temperatures of 220 to 260 ° C with mass loss of 2 to 5% the original sample, resulting in an elastic form of the material. The following table shows the mass losses experienced by a preferred embodiment of the inventive composition.

Mass loss chart Note that at least 50% mass loss occurred during the liquid and plastic states, before the plastic / solid state. Since less than 6%, and preferably no more than 4% of the original mass is lost in a solid state, the cracking problems of previous sol-gels are avoided. For application in conventional fiber optic networks, the ideal refractive index could be approximately 1.4565 for coating layers and 1.465 for waveguide centers at 632 nm. Compositional effects, such as the inclusion of methyl modifiers, or structural effects, such as porosity in the material, can significantly reduce the refractive index. Other compositional effects such as the inclusion of phenyl modifiers or the incorporation of germanium oxide or titanium oxide can significantly increase the refractive index. Preferably, the refractive index of the waveguide center falls on the scale of 1.4-1.55 and the refractive index of the coating falls on the scale of 1.3-1.6. The refractive index can be preferentially varied by incorporating in the composition phenyltrialkoxysilane, phenyltrifluorosilane or combinations thereof. Compositions containing 0.04 moles of silicon and containing components having phenyl groups directly attached to silicon atoms can be prepared. The refractive index at 588 nm was measured by comparison with a series of oils with standard refractive index using Becke's line method. The chart below details the silicon ratio of the different compositions and their refractive indexes. The refractive index data for these compositions shows the ability to adjust the refractive index to a desired value between 1.39 and 1.55.

The above description details a precursor material of central composition and a precursor material of coating composition. It also describes how to process the precursor material for coating composition or core composition.

C. Specific examples of materials used to form flat optical waveguide devices The invention is further described in relation to the following specific examples. A suitable material for this invention is a silsesquioxane. based on sol-gel. The material is made of a multicomponent mixture of alkyl- and arylalkoxysilanes, fluoride and water.

C.1 Synthetic Preparation I The following describes a process for forming a core or coating composition starting from a precursor material of core composition or coating. The preparation is based on a silicon formulation of 0.03 mol with 8 mol% equivalent of PDMS (polydimethylsiloxane), 73% of MTES (methyltriethoxysilane) and 19% of PTES (phenyltriethoxysilane). This will provide a material with a refractive index of about 1.4565 to 632 nm (coating formulation). The composition for a central index (1,465) is shown in. { brackets} .

Volumes 1) PDMS 0.18cc 2) MTES 4.36cc. { 3.95cc} 3) PTES 1.40cc. { 1, 88cc} 4) HF (48% p) 0.28cc 5) H2O 0.55cc HF and PTES are mixed in a closed nalgen container. The mixture is then heated in a water bath at 75 ° C for 15 to 30 minutes. This step pre-hydrolyzes and fluorides the PTES component of the mixture. The MTES and PDMS are then added to the mixture and heated for an additional 15 to 30 minutes. Finally the water is added. Approximately 1 to 3 minutes of stirring are required to homogenize the solution after the addition of water. The sol-gel hybrid is aged for 3 to 6 hours at 75 ° C. The sun should be clear with low viscosity after cooling. The sun in this state is suitable to form a thin coating. In this way, the sol forms a coating composition material or a central waveguide composition. After heating, the films look very transparent and free of cracks under the microscope. The sun can be dried to a "dry" shape free of ethanol by pouring a sun and allowing the ethanol to evaporate. This form of the material is suitable for transfer molding applications to form waveguide centers. To dry the sun, place 1 gram of it in a Pyrex 10cc beaker with 2.5 cm diameter. One gram of sun will dry to approximately 0.39 grams of dry sun. The dry sol will be reduced to 0.34g after heating to 240 ° C. The most suitable heating program to process both films and monoliths is to raise at 1 ° C per minute to 240 ° C, wait for 10 minutes and then cool at 1 to 2 ° C per minute. Slow speed may not be required, but it is convenient for nightly warm-ups. The discs are transparent and colorless.

C.2 Synthetic preparation II The following describes an alternative process and formulation for forming a core or coating composition. The following formulation removes the PDMS and uses diphenyldimethoxysilane instead. The formulation provides longer counter life, but is more prone to cracking during heating either in the form of a thin film or when monoliths are made.

Volumes 6) MTES 5.14cc. { 4.78} 7) DPDMS 0.545cc. { diphenyldimethoxysilane} 8) PTES 0.435cc. { 0.87cc} 9) HF (48% p) 0.28cc 10) H2O 0.55cc The preparation is similar to Synthetic Preparation I described above: HF is added to the mixture of PTES and DPMS, and allowed to react for 30 minutes at 75 ° C. The MTES is then added, and heated for an additional 30 minutes. The water is finally added, and it is stirred until it is transparent. It is aged for 3 hours at 75 ° C. This material handles similarity with the first formulation, except that the masses retained of 1 gram of sol are 45% when drying and 38% when curing at 250 ° C. Films and gels with this formulation are transparent during drying and curing, and are colorless when viewed through the edge. In Figure 7 an almost infrared absorption spectrum of a 1 mm disc of this material is provided.

C.3 Synthetic preparation lll Next, another alternative method and formulation for forming a central or coating composition is described. This method employs phenyltrifluorurosilane as the source of fluoride instead of HF. The inorganic-organic hybrid materials made with this method of preparation are suitable for forming monoliths and highly transparent and crack-free films. The formulations are given for a coating composition and a central composition in. { } .

Volumes, ce Coating. { Center} 11) PDMS 0.18. { 0.18} 12) MTES 4.27. { 3.89} 13) PTES 0.84. { 1.30} 14) PTFS 0.365. { 0.365} 15) H2O 0.745. { 0.745} The PDMS, MTES, PTES and PTFS are mixed together in a capped container of polypropylene or nalgen. The mixture is heated at 75 ° C in a hot water bath for 5 minutes to homogenize. H2O is added to the hot mixture and recapped. The phase of the mixture is initially separated. Heat to 75 ° C and stir vigorously until the solution is clear, usually around 20 minutes. The system is allowed to react for three hours before cooling. The composition must be transparent and fluid. The material handles similarity with the first formulation. The mass retained on drying is approximately 45% and after curing at 250 ° C the mass retained is 40% of the original sample. 1 mm thick discs were made by drying and curing a sample in a cylindrical mold. In FIGS. 5 and 6, almost infrared absorption spectra of a coating sample are given. The liquid sol compositions described above (synthetic preparation 1 and synthetic preparation II) are used as a composition for coating layers and center layers with patterns in flat waveguide devices. The following sections describe the procedure for forming the coating and core layers with patterns.

D. Process for forming a flat optical waveguide device Two different processing steps are required for the formation of flat waveguides, deposition of thin continuous films for coating layers and deposition of thin films with patterns for central layers. These will be described independently. To avoid the introduction of cracks, the coating procedures must, in general, be conducted in environments with low content of particulate materials. Soles are prepared in a standard laboratory environment and then taken to clean room conditions. The substrates are cleaned and dried in the clean room. The suns are passed through 0.2 micron filters before being applied as coatings to remove any particulate matter. All drying should preferably be conducted in the clean room, and heating should be done either in the clean room or by techniques that minimize the introduction of particles to the surface in a standard laboratory environment.

D.1 Coating layers Two basic techniques may be required. A uniform coating layer may be required to support a core layer if a substrate is not able to function as a coating layer in the designed flat waveguide device. When a coating layer is for coating a patterned central arrangement, it is necessary to fill regions that could form bubble traps, especially Y-type features, or waveguide links with an eternal protrusion. Each of these coating techniques are described here. To make a liquid sol film (coating composition) of discrete thinness, any of a number of liquid phase deposition methods can be employed. A cleaned substrate can be submerged in the sol-gel and removed at a fixed rate to generate a coating. The thickness of the lining is proportional to the pull-out speed. A liquid sol film can be spun on a flat surface, first saturating the surface that will be coated with the liquid sol and then spinning at a speed of 1000 to 4000 RPM. The thickness is inversely proportional to the spin speed. A film can be prepared simply by draining excess sun from a saturated surface. The most successful method of overcoating an edge arrangement with waveguide center patterns is to drip the fluid sun over the inner protruding waveguide arrangement and allow the sun to wet the region between the inner protrusions. This is especially important when the arrangement includes Y-shaped branch elements, because when these characteristics are coated by immersion or centrifugation very quickly, the bubbles can be trapped in the closed regions. Once the entire surface is well moistened and all features are full, a drainage or spin coating technique can be employed to provide sufficient thickness. In these cases, the surface is saturated with sun, and then drained or spun to provide sufficient coating material. It is also possible to simply provide the adequate volume of sol to the substrate to provide a sufficient final coating thickness and allow gravitational expansion for the necessary thickness uniformity. The biggest barrier to this simple method is that the evaporation of alcohol, a by-product of reaction, causes the viscosity to increase quite rapidly, so coating a large sample in this way becomes difficult. By any of the above techniques, the final film is processed with drying and thermal treatments to give the final silsequioxane compositions. The film is allowed to air dry for 15 minutes to one hour at temperatures between 20 and 45 ° C. The sample is then transported to an oven and cured. The curing program that is preferred is to raise the temperature from 25 to 240 ° C at 4 ° C / minute; keep it for 60 minutes and then bring it from 25 ° C to 4 ° C per minute.

Various key attributes of the process and the material make it possible to apply advantageous overcoating layers. The compositions have low intrinsic optical loss. The ability to control the refractive index makes design flexibility possible. Also important is the ability to coat a thick film with a low viscosity sol (coating layer composition), and then convert that film into a solid film of 40 microns thick without cracking or large residual stresses. This is a significant problem in classical completely inorganic soi-gei techniques where cracking prevails when the thickness of the film exceeds approximately 1 miera. The described compositions show excellent environmental durability.

D.2 Central layers with patterns According to an illustrative embodiment of the invention, the arrangements of waveguide centers can be formed using either a transfer printing technique or an enhancement technique. The goal is to achieve a high resolution pattern with a high index core composition that takes advantage of the unique attributes of the sol-gel compositions to produce waveguide arrays quickly with low processing cost. Generally, two methods will be described. These techniques replace the lithographic techniques of the prior art to form arrays of waveguide centers.

Both approaches (impression and enhancement) take advantage of the ability to dry the composition in liquid gel and sol to a viscous form. A scalpel may be passed over the viscous material or rolled into a mold such as an Intaglio image forming plate, or it may be enhanced by a moide to achieve pattern formation. The thermal cure can then establish the structure before the material is released from the mold. As shown in Figures 3A, 3B, 3C, 3D and 3E, in the first of the approaches, the desired pattern 32 is provided in negative relief on a negative master film 30 which is compressible to conform to the substrate region to form a "foot" or compressed region (step A). The negative master film 30 is a film in which the central pattern is pressed on the surface of the film and can be formed by the following procedure. A desired waveguide pattern is recorded on a silicon disk (not shown). The disc is then coated with a suitable material that can be separated from the silicon disc with complete repiication of the pattern to form the negative master film 30. Furthermore, the selected material must have suitable release properties with the inventive materials of the present invention . Nickel is a material that provides both the ability to separate from the surface with a silica pattern and the ability to provide a suitable release surface for the materials of the invention. The nickel can be deposited on the silica plate by means of non-electrolytic deposition or other known method. The nickel film is then detached from the silica plate to form the master negative 30. Preferably, the master nickel negative 30 is mounted on a flexible backing 33, such as an elastomer. The dry sol material 34 is loaded into the relief channels 32 in the nickel master 30. This can be done using, for example, a scalpel 35 or preferably a roller apiicator. The excess sun is removed from the surface (step A). Passing a scalpel works well to force the sun into the pattern and to eliminate the excess. A roller works well because it causes a positive meniscus, which helps in contact and fixation to the substrate. The material of the invention is then cured to a point where it can retain its shape, and still adhere to the substrate 36 of the flat optical device that will be formed. The substrate 36 is contacted with the nickel master 30, simultaneously contacting the material of the invention 34 in the channels 32. The compressible nickel master 30 preferably contacts the substrate 36 only in a single "foot" 37 located in a moment rolling the master material along the surface. Preferably, the sol-gei is compressed against the substrate 36 and cured simultaneously using, for example, a source of heat or radiation 38. Upon separation of the nickel master material 30 from the substrate 36 and release of the material of the invention 34 from the nickel master material 30 and adhering to the substrate surface by positively relieving the waveguide arrangement (step C). An overcoat layer 39 is deposited and the material is then finally cured at a temperature of 240 ° C (step D). Figures 3F and 3G show a variation of the focus illustrated in Figures 3A, 3B, 3C, 3D and 3E. First, a second plate 31 is pre-coated with overcoating material 39. A positive master film 30 in which the central pattern is raised on the surface of the master is in contact with the second plate 31. When the master film 30 is rolled up along the overcoating material 39, depressions are formed in the overcoating material 39 by contact with the desired pattern 32 in the positive master film 30. The overcoating material 39 is also preferably cured simultaneously with a curing device 38, such as a source of heat or radiation (step A). Then, the dry sol material 34 is loaded into the depressions using, for example, a scalpel 35. The sol material may be partially cured with the curing device 38 (step B). Preferably, the coating material and sol-gel material are cured simultaneously by focused or localized radiation while in contact. Then, the combination of the sol material 34 and the outer coating material 39 contacts the subcoating 39 'on the substrate 36 and is preferably cured simultaneously with a curing device 38 (step C). As a result, the center is deposited on the substrate already embedded in the overcoating 39. As described above, it may be desirable to place a lower coating layer 39 'on the substrate 36 before depositing the sol material 34 and the overcoating 39. Figures 3H and 31 show another variation of the approach illustrated in Figures 3A, 3B, 3C, 3D and 3E. A second plate 31 is pre-coated with overcoating material 39 (step A). Then, the dry sol material 34 is placed on an embossed pattern 32 in a negative master film 30 using, for example, a scalpel 35. The sun material may be partially cured with the curing device 38. The sun material contacts afterwards. with the overcoating material 39 on the second plate 31 and the outer coating material is adhered (step B). Preferably, the coating material and material of the invention in the channels of the negative master film 30 are simultaneously cured by focused radiation or localized heat while in contact. After separation of the second plate 31 from the negative master film 30, the material of the invention in the channels remains adhered to the overcoat 39 on the surface of the second plate 31, forming a high pattern of the core material thereon. Then, this pattern can be additionally overcoated by an additional layer of overcoating 39"This can be either a continuous overcoat or be deposited or printed as overcoating between the raised pattern by letterpress, microsupply, inkjet printing or the like. In the non-continuous case, the deposited material must exhibit a positive meniscus adjacent to the raised (raised) pattern to completely envelop the core material after it is transferred to the substrate, then the combination of the sol material 34 and the overcoating material 39 makes contact with the substrate. with the substrate 36 and are preferably cured simultaneously with a curing device 38 (step C.) As a result, the center is deposited on the substrate already embedded in the overcoating 39. As mentioned above, it may be desirable to put a sub-coating 39 on the substrate 36 before depositing the sol material 34 and the overcoating 39. When this is done, the need for a second application of the overcoat 39"on the plate 31 can be obviated. In a preferred embodiment of the invention, the material changes state of the liquid to the solid when under compression (i.e. , while in contact with the substrate). The cohesion of the material on the substrate causes the material to remain on the substrate while the compressed master film is separated from the substrate. The change of state can be achieved by heat or radiation (light), which can be focused on the compressed area (the "foot") or, in the case of heat, heating the substrate. It is possible, but less desirable, to use cooling or drying to obtain the change of state. A number of variations in the technique can be considered important for the optimization of pattern replication and for minimizing costs. The surface to which the negative master film is attached can be flat or curved like in a drum. A curved surface has many advantages in elimination, wherein the drum can be loaded with sol-gel material, passed through a scalpel, heated and applied in a continuous process. One advantage is to avoid air entrapment. The detachment of the gel from the negative master film to the substrate will occur along a single front rather than over the entire area of the pattern, which will reduce stresses and very possibly reduce cracks. The curing conditions are another series of variable procedures. The heat treatment can occur in discrete steps, or it can be introduced as part of either the step of passing a scalpel or transferring the procedure. The nickel master film can be heated, with the transfer to a cold substrate, or the master film can remain cold and the substrate be heated so that the transfer and curing is achieved upon contact with the substrate. The detachment of the master film can also be improved by release agents. The substrate can be coated with coating material to facilitate transfer and the added overcoat to embed the centers 34 in the coating. In the second approach, an enhancement technique is employed to provide the desired waveguide arrangement pattern. This approach is illustrated in Figures 4A, 4B, 4C, 4D and 4E. As shown in Figures 4A, 4B, 4C, 4D and 4E, the enhancement element 42 incorporates a positive relief structure 44 of the central waveguide arrangement. That is, the enhancement element is a positive master element in which the central pattern is raised above the surface of the element. As shown in step A, the substrate 40 is coated with a low index sol-gel coating layer 41 with a depth greater than the maximum depth of the central waveguide arrangement. The coating layer 41 is partially cured to a point where the viscous flow still permits deformation without cracking, or is heated to soften by creating a viscous flow and then cooled instantaneously. The enhancement element 42 is pressed on the coating layer 41. Heat is applied to cure the film to an elastic state (step B). The enhancement element 42 is then raised to provide a negative relief pattern 46 in the coating layer 41 (step C). To complete the structure, a high index waveguide central composition 48 is then passed through a scalpel in the negative relief regions 46 of the liner 41 and is cured (step D). Finally, a coating layer 50 is deposited on the cover layer with filled center 41 to provide a channel waveguide structure (step E). A number of variations in technique may be important to consider the optimization of pattern replication and to minimize costs. The enhancement element should be detached from the coating layer to minimize defects that arise from adhesive removal. Preferably, the enhancement element is formed with a surface quality and a roughness equal to that of the glass surface on which it is being deposited. Nickel could be a suitable material for the same reasons that were indicated in the Intaglio printing process. The silica may require release agents. It would be desirable to mount the enhancement element on a curved element, such as a drum, so that the detachment point is a compressed "foot" region instead of a two dimensional area so that lower detachment stresses are experienced. Curing could be achieved in discrete processing steps. Alternatively, the step of curing the plastic to elastic states could be achieved by heating the enhancement element and imparting both the shape and energy needed to cure in one step. The exact degree to which a first sol-gel layer must be cured before the next sol-gel layer is applied may be variable in some cases. The final curing could then effectively cure all three layers. Although the compositions and methods described so far use only thermal curing processes for the conversion of the sol-gel material from the plastic to the elastic state, additives for the formulations could make possible the photocuring with UV radiation or visible light radiation. In this case, the light can be transmitted through the substrate in the compressed region. In any case, if light is used for curing, at least one of the film or substrate must be made of a material that is transparent to light. Preferred substances include fused silica, soda-lime, borosilicate glass or a fluorocarbon polymer such as FEP (fluorinated ethylene-propylene). The methods described above allow to form structures having a resolution (i.e., a width of a center can measure) of less than 1.0 miera and preferably less than 0.6 micras.

E. Examples of flat optical waveguide devices In combination, a complete planar optical waveguide structure can be made, or if desired, an overcoat layer can be provided over a conventionally recorded silicate-type waveguide arrangement. The main advantage that can be obtained with this invention is the cost. The use of the overcoat of the invention in conventional glass wave guide arrangements conventionally engraved can provide advantages. The low processing temperatures used prevent any deformation of waveguides with internal core rslate recorded, while the procedure at high temperatures can distort the original shape of the waveguide. The low temperature and low modulus of the overcoating of the invention also results in low voltage fields on the waveguides with an external highlight, whereby voltage induced polarization effects can be minimized.

E.1 Example of overcoating A straight waveguide arrangement was overcoated to measure the overcoating and covering characteristics. A silica wafer was coated with a glass core layer by flame hydrolysis methods and patterned by photolithographic and reactive ion etching methods. A fragment (2 cm x 2 cm) was cut from a wafer with a diameter of 10 cm which had a straight waveguide arrangement. A liquid sol composition was prepared according to the present invention with an objective index of 1455 at 632 nm. In a clean room, the sun was filtered through a 0.2 micron filter to remove matter into large particles. The fluid sol was placed by dripping on the waveguide arrangement, first moistening the length of the waveguides with internal protrusion and then saturating the entire surface of the fragment. The sample was tilted and an absorbent towel was used to remove excess matter. The coated fragment was then flattened and allowed to dry for about one hour. The sample was then placed in an oven at 100 ° C for one hour. The sample was then transferred in a covered container from the clean room to an oven outside the clean room. The thermal process was completed by heating at 240 ° C at 1 ° C per minute for 10 minutes, and then cooling at 1 ° C per minute. The losses at a wavelength of 1550 nm measured for this sample were approximately 0.5 db per cm and the beneficial transmission characteristics were measured in the optical telecommunications windows within 1200-1600 nm.

E.2 Example of center with pattern A laboratory sample procedure is described to make a center with pattern. A negative nickel master material was prepared by electroplating a film onto a silica wafer that had previously been etched with reactive ion (RIE) to provide straight waveguides and 1 x 8 spacers. The film (approximately (0.10) mm thick) was peeled off from the silica master material and mounted on a flat silica wafer with double-adhesive tape.The resulting nickel surface was flat only over limited regions of the specimen.A sol was prepared and allowed to dry to provide a viscous fluid A drop of material was placed on a flat region of the nickel film and expanded in the relief pattern by passing a scalpel Excess material was removed from the surface with the scalpel leaving sun in the relief channels negative of the negative master material A silica disc with a diameter of 25.4 mm was pressed on the filled region of the negative master material and loaded on a weight of 10 grams The heavy sample was placed in an oven at 75 ° C for 12 hours and then further heated at 120 ° C for 1 hour. After cooling, the weight was removed. A spatula was used to lift the disc from the film. The disc burst the nickel surface, sending a large part of the filled gel material out of the channels. The silica disc with adhered internal waveguides was then heated to 240 ° C at 1 ° C per minute, maintained for 10 minutes and then cooled at a rate of 1 ° C per minute. The waveguides replicated the width of the channel and had well-defined edges, and the seamless surfaces showed that the sol-gel material is detached well from the nickel film.

F. Spectra of materials used to form flat wave guide devices The sol-gel materials used in the present invention have interesting spectra. These spectra are illustrated in Figures 5, 6 and 7. Samples of 1 nm thick spectra of the inorganic-organic hybrid solid material of the invention comprising methylsiloxane groups, phenylsiloxane groups and fluorine groups were analyzed according to normal methods of near IR visible spectrum analysis. The reflection and dispersion losses are taken into consideration by establishing a baseline 101. The fixed spectra are typical for the preferred composition scales of inorganic-organic hybrid solid materials.

Figure 5 is a spectrum showing the almost visible IR scale of 300 nm at 2500 nm, and Figure 6 is an insert enclosed in a box of that spectrum showing near-infrared. The telecommunications windows are centered at 1310 nm (a scale of approximately 1270-1330 nm) and 1550 (a scale of about 1525-1570 nm), in both cases the intrinsic absorption of the materials of the invention at these wavelength scales is very low when measured from the baseline 101. One band is present at 1520 nm, as seen in figure 7, which is apparently due to a band in combination of CH and SiOH vibrations. As shown in the figures, at the scales between 1270-1330 nm and 1525-1570 nm, the absorbance is very low. This baseline absorbency is due to the losses of reflection and surface dispersion and does not represent any intrinsic absorption in the sample. With a base line at 0.195 AU, a small peak at approximately 1530 is approximately 0.03 AU, which translates to approximately 0.3 dB / cm. Figures 6 and 7 show how the absorbency is further reduced by deuterating the material of the invention. In Figure 6, peaks 102 move to 202, and peak 303 moves to 203 by replacing the hydrolyzer with deuterium. The calculated spectral positions of equivalent characteristics in a completely deuterated system are provided in Figure 7. Deuteration in methyl and phenyl groups is achieved by synthesis of the precursors, and in silanol by hydrolysis with D2O. Of these deuteration procedures, the easiest to practice is hydrolysis with D2O, because this form of water is readily available. Figure 7 shows that a reduction in the spectral intensity of the silanol peak at 1380 nm and the band in combination at 1520 can be achieved using D2O instead of water in the preparation. The presence of any peak intensity in these regions is due to the fact that HF was used in the synthesis along with its water (H2O) of hydration that provides 1/3 of all the water necessary for the hydrolysis reactions. Particularly useful attributes of the described formulation are its transmitting properties at 1310 nm (1270-1330 nm) and at 1550 nm (1525-1570 nm, preferably 1530-1565 nm). In general, the optical spectrum in the almost IR of hybrid materials is dominated by vibratory overtones that come from the organic modifiers and silanol groups reacted incompletely. The formulations according to the present invention have been carefully designed to provide a minimum number of vibration modes so that the overtone and the band spectrum in combination in the near IR are as uncomplicated as possible. In composition, only the C-H and SiO-H extensions and the phenyl group flex modes are active in the near IR. The positions of the C-H extension overtone bands are from 1630 to 1750 nm and 1150 to 1200 nm. The position of the silanol extension band is from 1370 to 1410 nm. Ring bending of the phenyl group is active in the region of 1700 to 2000 nm. Of these modes of vibration, only silanol is not an essential part of the structure, originating from the incomplete condensation of the siloxane network. The content of silanol is low and minimized in these formulations by the incorporation of fluoride and by the unusual ability of the material to proceed to a high degree of condensation while still in a viscous state. The importance of the low silanol content in the final product is that the undesired combination bands are minimized.

In this way, the absorbance has been brought to very low values in the optical telecommunication windows at 1310 nm (1270-1330 nm) and at 1550 nm (1525-1570 nm). This makes the formulation especially useful for telecommunications applications. The compositions of the invention provide particularly suitable transmission with low absorption at the wavelength scales of 1200-1360 nm and 1430-1620 nm. The compositions of the invention have a particularly suitable transmission at the preferred scales of 1220-1330 nm, 1525-1570 nm and the most preferable scale of 1530-1565 nm. In the 1200-1600 nm scale, the material of the invention provides high transmission and an absorbency of less than 0.2 AU. At the 1525-1570 nm and 1270-1330 nm scales, the material of the invention can provide an absorbency of less than 0.1 AU, preferably less than 0.05 AU and more preferably less than or equal to 0.03 AU. The embodiments of the material of the invention with such low absorbency and high transmission characteristics provide an optical waveguide material with losses of less than 0.4 dB / cm, preferably less than 0.3 dB / cm, more preferably less than 0.1 dB / cm and even more preferably less than 0.05 dB / cm. In some cases, even the low losses observed with these compositions can be problematic. To the extent that absorption residues or bands in combination can cause window losses of 1310 or 1550 nm, hybrid materials can be made to reduce such absorption using precursors with deuterium organic groups (deuteration). When precursors such as CD3Si (OC2H5) 3 and C6D5Si (OC2H) 5 are used, the siloxane network is modified with CD3 and CeD5 groups. The vibrating frequencies C-D move to lower energies in the same way C-H, and the overtones are then displaced as well. In this way, the general absorbency in the almost IR region can be reduced so that the absorption residues are smaller and the interference characteristics are higher order overtones, which have fundamentally lower intensity. The use of deuterium oxide as the source of water can also minimize the effect of SiOH absorption at 1380 nm since the absorbance position of SiO-D is at approximately 2000 nm. Finally, the embodiments of the invention described above are designed to be illustrative only. Numerous alternative embodiments may be envisioned by those skilled in the art without departing from the spirit or scope of the following claims.

Claims (67)

1. NOVELTY OF THE INVENTION CLAIMS 1. A planar optical waveguide formed on a substrate and comprising: a waveguide center having a first refractive index and a coating layer formed contiguously with said center and having a second refractive index smaller than said first refractive index; at least one of said center and said coating layer being an inorganic-organic hybrid material comprising an extended matrix containing silicon and oxygen atoms with at least a fraction of the silicon atoms being directly bound to substituted hydrocarbon portions or not replaced. 2. The plane optical waveguide according to claim 1, further characterized in that the first refractive index is on a scale of 1.4-1.55 and the second index of refraction is on a scale of 1.3-1.6. 3. The flat optical waveguide according to claim 1, further characterized in that the hybrid organic-norwegian material has an aita transmission and an absorbance of less than 0.
2. 2 AU for wavelengths on a scale of between 1200-1600nm . 4. The plane optical waveguide according to claim 3, further characterized in that the inorganic-organic hybrid material has high transmission and an absorbance of less than 0.05 AU for wavelengths on a scale between 1525-1570 nm. 5. The plane optical waveguide according to claim 3, further characterized in that the inorganic-organic hybrid material has an aita transmission and an absorbance of less than 0.05 AU for wavelengths on a scale between 1270-1330 nm . 6. The plane optical waveguide according to claim 4, further characterized in that the absorbance on the scale between 1525-1570 nm is less than 0.4 db / cm. 7. The optical waveguide piaña according to claim 5, further characterized in that the absorbance on the scale between 1270-1330 nm is less than 0.2 db / cm. 8. The flat optical waveguide according to claim 1, further characterized in that the inorganic-organic hybrid material has a mass loss of less than 6% of the original mass when the material changes from a non-solid to a solid 9. The plane optical waveguide according to claim 1, further characterized in that the inorganic-organic hybrid material has a mass loss not greater than 4% of the original mass when the material changes from a non-solid to a solid . 10. The flat optical waveguide according to claim 1, further characterized in that the inorganic-organic hybrid material loses approximately 50% of its original mass before being cured to form a solid. 11. The flat optical waveguide according to claim 1, further characterized in that the inorganic-organic hybrid material is deuterated. 12. The flat optical waveguide according to claim 1, further characterized in that said second coating layer is formed on said center and wherein said waveguide includes an additional coating layer formed between said substrate and said center. 13. The flat optical waveguide according to claim 1, further characterized in that the hybrid organic-organic material comprises methylsiloxane, phenylsiloxane and fluorine groups. 14. The flat optical waveguide according to claim 1, further characterized in that the inorganic-organic hybrid material is provided by curing precursors comprising polydimethylsiloxane, methyltriamyxysilane and phenyltrialkoxysilane. 15. The flat optical waveguide according to claim 1, further characterized in that the hybrid organic-organic material is provided by curing precursors comprising PDMS, MTES, PTES and PTFS. 16. A flat optical device formed on a substrate and comprising: an arrangement of waveguide centers guiding optical radiation, and a coating layer formed contiguously with said arrangement of waveguide centers to confine said optical radiation to said arrangement of waveguide centers; at least one of said arrangement of waveguide centers and said coating layer being an inorganic-organic hybrid material comprising an extended matrix containing silicon and oxygen atoms with at least a fraction of the silicon atoms being directly bound to substituted or unsubstituted hydrocarbon portions. 17. The optical device according to claim 16, further characterized in that said device is a separator. 18. The optical device according to claim 16, further characterized in that said device is a coupler. 19. The optical device according to claim 16, further characterized in that said device is a wavelength division multiplexer. 20. The optical device according to claim 16, further characterized in that one of said centers and said coating layer comprises a hydrolyzed and poiimerized siian selected from the group consisting of tetraalkoxysilanes, alkyltrialkoxysilanes and aryltrialkoxysilanes. 21. The optical device according to claim 20, further characterized in that the content of the hydrolyzed and polymerized silane is at least 50%. 22. - The optical device according to claim 16, further characterized in that the hydrocarbon portions are hydrolyzed products of a modifier selected from the group consisting of inert network modifiers, active network modifiers, organic network forming modifiers, reactive polymeric modifiers and polymeric reactive modifiers. 23. The optical device according to claim 16, further characterized in that the hydrocarbon portions are unsubstituted or substituted alkyl or aryl portions. 24. The optical device according to claim 23, further characterized in that the substituted alkyl or aryl portions are selected from the group consisting of an aminoalkyl, a hydroxyalkyl, a carboxyalkyl and mercaptoalkyl. 25. The device according to claim 16, further characterized in that said one of said center arrangement of said coating layer comprises the hydrolysis product of an interpenetrating organic polymer matrix. 26. The device according to claim 25, further characterized in that there are substantially no covalent bonds between the interpenetrating organic polymer matrix and the extended silicon-oxygen matrix. 27. The device according to claim 22, further characterized in that the hydrolyzed and polymerized product of the modifier forms an organic network that is covalently linked by a Si-C bond. 28. The device according to claim 16, further characterized in that said one of said center arrangement and said coating layer contains fluorine. 29. The device according to claim 16, further characterized in that said one of said center arrangement and said coating layer contains an element for regulating the refractive index. 30. The device according to claim 29, further characterized in that said element is Ge or Ti. 31.- A flat optical waveguide formed on a substrate and comprising: an arrangement of waveguide centers in which optical radiation is propagated, a coating layer for confining said optical radiation to said arrangement of optical guidance centers; waves; said arrangement of centers comprises a first inorganic-organic hybrid material comprising an extended matrix containing silicon and oxygen atoms with at least a fraction of the silicon atoms being directly bound to substituted or unsubstituted hydrocarbon portions; said coating layer comprises a second inorganic-organic hybrid material comprising an extended matrix containing silicon and oxygen atoms with at least a fraction of the silicon atoms being directly bound to substituted or unsubstituted hydrocarbon portions; said second material has a lower refractive index than said first material. 32. A method for forming a flat optical device comprising the steps of: preparing a precursor material of central waveguide composition comprising at least one silane and a source of substituted or unsubstituted hydrocarbon portions; partially hydrolyzing and polymerizing the precursor material of central waveguide composition to form a central waveguide composition; using a mold, forming an arrangement of optical waveguide centers comprising said central waveguide composition and completing the hydrolysis and polymerization of the central waveguide composition under effective conditions to form an inorganic-organic hybrid material comprising an extended matrix containing silicon and oxygen atoms with at least a fraction of the silicon atoms being directly bound to substituted or unsubstituted hydrocarbon portions. 33.- The method according to claim 32, further characterized in that the mold allows the step of forming an arrangement includes the formation of structures that have a resolution of less than 1 miera. The method according to claim 32, further characterized in that the mold allows the step of forming an arrangement to include the formation of structures having a resolution of less than 0.6 microns. 35. - The method according to claim 32, further comprising the step of choosing the mold to be an Intaglio image formation plate. 36. The method according to claim 32, further characterized in that the step of forming an arrangement further comprises: (a) charging a negative master film with said central waveguide composition; (b) compressing the negative master film and the central waveguide composition against a substrate and simultaneously curing the central waveguide composition and (c) detaching the negative master film from the central composition. 37. The method according to claim 32, further characterized in that the step of forming an arrangement further comprises: (a) covering a plate with coating material; (b) using a positive master film, forming depressions in the coating material; (c) charging said central waveguide composition in the depressions; (d) compressing the central waveguide composition and the coating material against a substrate and simultaneously curing the core composition and the coating material and (e) detaching the plate from the core composition and the coating material. 38. The method according to claim 37, further characterized in that the curing further comprises thermal curing. 39. The method according to claim 37, further characterized in that the curing further comprises curing with light and selecting at least one of the substrate and the plate to be transparent. The method according to claim 32, further characterized in that the step of forming an arrangement further comprises: (a) covering a plate with coating material; (b) loading said central waveguide composition into a negative master film; (c) adhering said central waveguide composition to the coating material; (d) compressing the central waveguide composition and the coating material against a substrate and simultaneously curing the core composition and the coating material; and (e) detaching the plate from the core composition and the coating material. 41. The method according to claim 40, further comprising after the adhesion step; the overcoating of the core composition and the coating material with an additional layer of coating material. 42. The method according to claim 40, further characterized in that the adhesion step further comprises contacting said central waveguide composition and the coating material while simultaneously curing said central waveguide and material composition. coating. 43. - The method according to claim 40, further characterized in that the curing step comprises thermal curing. 44. The method according to claim 40, further characterized in that the curing step further comprises curing with light and selecting at least one of the substrate and the plate to be a transparent material. 45. The method according to claim 32, further characterized in that the step of forming an arrangement further comprises: (a) coating a substrate with coating material; (b) partially curing the coating material; (c) pressing a highlighting element into the partially cured coating material; (d) curing the enhanced coating material; (e) filling the enhanced coating material with the central waveguide composition and (f) curing the central waveguide composition. 46. The method according to claim 45, further characterized in that the curing further comprises thermal curing. 47. The method according to claim 45, further characterized in that the curing further comprises curing with light and selecting the substrate and making it transparent. 48. The method according to claim 32, further characterized in that the precursor material of the central waveguide composition comprises PDMS, MTES and PTES. 49. - The method according to claim 32, further characterized in that the precursor material of central waveguide composition comprises MTES, DPDMS and PTES. 50.- The method according to claim 32, further characterized in that the precursor material of central waveguide composition comprises MTES, PTES, PDMS and PTFS. 51.- The method according to claim 32, further comprising the steps of: forming a coating layer on said arrangement of waveguide centers according to a method comprising the steps of: (a) preparing a material coating composition precursor comprising at least one silane and a hydrocarbon portion source, (b) partially hydrolyze and polymerize the precursor material of coating composition to form a coating composition; (c) applying by liquid phase deposition a coating of said coating composition to said array of waveguide centers and (d) drying said coating composition to form a coating layer on said array of guide centers; waves. 52. The method according to claim 51, further characterized in that said coating layer comprises an inorganic-organic hybrid material comprising an extended matrix containing silicon and oxygen atoms with at least a fraction of the silicon atoms being directly attached to substituted or unsubstituted hydrocarbon portions. 53. The method according to claim 51, further characterized in that said coating composition precursor material comprises PDMS, MTES, PTES, or combinations thereof. 54. The method according to claim 51, further characterized in that the precursor material of coating composition comprises MTES, DPDMS, PTES, or combinations thereof. The method according to claim 51, further characterized in that the coating composition precursor material comprises, MTES, PTES, PDMS, PTFS, or combinations thereof. 56.- A method for forming a flat optical device on a substrate, comprising the steps of: forming an arrangement of waveguide centers and forming a coating layer on said arrangement of waveguide centers by the steps of: (a) preparing a coating composition precursor material comprising at least one silane and a hydrocarbon portion source; (b) partially hydrolyze and polymerize the precursor material of coating composition to form a coating composition; (c) applying by coating liquid phase a coating of said coating composition to said array of waveguide centers and (d) drying said coating composition to form a coating layer on said array of waveguide centers. The method according to claim 56, further characterized in that the coating layer comprises an inorganic-organic hybrid material comprising an extended matrix containing silicon and oxygen atoms with at least a fraction of the silicon atoms being directly attached to substituted or unsubstituted hydrocarbon portions. The method according to claim 56, further characterized in that a pattern is formed on said center arrangement by recording unmasked portions of a central layer. 59.- A method for forming a coating layer on a substrate in a flat optical device, comprising the steps of: (a) preparing a precursor material of coating composition comprising at least one silane and a source of portion of hydrocarbon, (b) partially hydrolyze and polymerize the precursor material of coating composition to form a coating composition; (c) applying a coating of said coating composition to said substrate by liquid phase deposition and (d) drying said coating composition to form a coating layer on said substrate. 60.- A method for forming a flat optical waveguide device, comprising the steps of: (a) depositing a first coating layer on a substrate, (b) printing a pattern of grooves in said first coating layer by applying a positive master film to said first coating layer; (c) inserting with a scalpel the central waveguide composition material in said grooves to form waveguide centers, (d) depositing a second layer of coating on said first coating layer and said waveguide centers. 61.- The method according to claim 60, further characterized in that the positive master film is compressible and comprises a film or foil on a flexible backing, and wherein the master film is applied by winding against said first coating layer. 62. The method according to claim 60, further comprising curing the waveguide center. 63. The method according to claim 62, further characterized in that the curing step comprises curing with light and further comprises selecting at least one of the substrate and the master film to be a transparent material. 64.- A method for forming a plane optical waveguide device, comprising the steps of: (a) filling a pattern of slots in a negative master film with a material of central waveguide composition, (b) applying the negative film to a substrate; (c) removing the master film to transfer the central waveguide composition material to the substrate to form a pattern of waveguide centers and (d) forming a coating layer on said pattern of waveguide centers. The method according to claim 64, further characterized in that the negative master film is compressible and comprises a film or foil on a flexible backing, and wherein the master film is applied by winding against said substrate. 66.- The method according to claim 64, further comprising curing the waveguide composition during the step of applying the negative master film to the substrate. 67.- The method according to claim 66, further characterized in that the curing step comprises curing with light, and further comprises selecting one of the substrate and the master film to be a transparent material.