Abstract: The present invention provides a method of forming a planar optical waveguide comprising the steps of forming a silica-based waveguide at a first temperature which is below a melting temperature of material from which the waveguide is formed; and annealing a region of the waveguide at a second temperature which is greater than the formation temperature and less than a melting temperature of material from which the waveguide is formed, so as to alter an effective refractive index of the region. In one embodiment the step of annealing is preceded by the step of forming a thin film heater over the region of the waveguide, the heater being capable of heating the region to the second temperature. The first temperature is preferably low (below 400° C.) to maximise the range of annealing temperatures.

Abstract: The invention resides in a method of forming a waveguide structure comprising the steps of forming a silica based waveguide on a substrate; annealing one or more localised regions of said waveguide to permanently set the refractive index profile of said localised regions relative to other regions of said waveguide. In a particular form of the invention a core-forming layer is formed and selected regions of the core-forming layer are annealed to reduce their refractive, index thereby defining a core region therebetween. Other applications of the invention reside in reducing bend losses in bent waveguides, and forming long-period gratings in planar waveguides.

Abstract: A method of depositing a dual layer top clad for an optical waveguide of a planar lightwave circuit (PLC). The method includes a first step of providing a high flow rate of a Boron dopant gas for a first top cladding layer deposition process. Then, a low flow rate of a Boron dopant gas is provided for a second top cladding layer deposition process. The second top cladding layer deposition process is performed directly on the first top cladding layer deposition. The first and second top cladding layer deposition processes are combined to form a dual layer top clad of the PLC having a high Boron portion covering a plurality of optical cores and a low Boron portion covering the first portion. The first top cladding layer deposition process can comprises three deposition and anneal cycles using the high flow rate for the Boron dopant gas. The three deposition and anneal cycles are used to fill gaps between the plurality of optical cores of the PLC.

Abstract: A method of making an optical waveguide structure having improved thermal isolation and stress reduction. The method etches both deep trenches and shallow trenches in a single step. The method includes the step of depositing a partial top clad layer over a first and second waveguide core. An etch back is then performed on the partial top clad layer to obtain a desired thickness of the partial top clad layer. A first hard mask layer is subsequently deposited over the partial top clad layer. A set of hard masks are then formed over the first and second waveguide cores by patterning and etching the first hard mask layer. A full top clad layer is then deposited over the partial top clad layer and the set hard masks to form a top clad. A second hard mask layer is then deposited over the top clad. A deep trench area and first and second shallow trench areas are then exposed by patterning and etching the second hard mask layer.

Abstract: A method of forming an oxide structure and an oxide structure formed by the method. In one embodiment a lower cladding layer on a substrate is provided. At least one core layer is formed on lower cladding layer, the core layer includes boron at a concentration that produces substantially zero internal stress of said core layer. At least one upper cladding layer is formed on the core layer wherein at least one of the upper and lower cladding layers include germanium at a concentration level such that the upper and lower cladding layers exhibit substantially equivalent refractive indices.

Abstract: The present invention provides a method of depositing a cladding layer over external surfaces of a waveguide structure formed on a planar substrate, the waveguide structure comprising a planar waveguide core formed on the planar substrate and a raised structure formed on the planar substrate adjacent the waveguide core. The invention allows high-aspect-ratio gaps in a planar optical waveguide structure to be filled without incorporating macroscopic or microscopic voids. In one embodiment, the method comprises depositing a cladding material over the planar waveguide structure, etching the deposited cladding material so as to reduce shadowing effects between the waveguide core and the raised structure during the deposition of the cladding material, and controlling at least one parameter of the deposition so as to form a cladding layer front the deposited material. In another embodiment, the method involves modifying the profile of the waveguide structure before depositing the cladding layer.

Abstract: The present invention relates to a method of manufacturing a waveguide using an ion exchange process. The present invention controls the refractive index and the thickness of a surface layer on a glass substrate using an ion exchange process, forms the waveguide pattern on the surface layer by means of photolithography and etching process and coats with materials having the refractive index same to or lower than that of the glass substrate to form a cladding layer. Accordingly, the present invention can manufacture a planar waveguide, which is excellent in dimension control and reproducibility and has a sharp step wall.

Abstract: A method of depositing a top clad layer for an optical waveguide of a planar lightwave circuit. A GeBPSG top clad layer for an optical waveguide structure of a planar lightwave circuit is fabricated such that the top clad layer comprises doped silica glass, wherein the dopant includes Ge (Germanium), P (Phosphorus), and B (Boron). In depositing a top clad layer for the optical waveguide, three separate doping gasses (e.g., GeH4, PH3, and B2H6) are added during the PECVD (plasma enhanced chemical vapor deposition) process to make Ge, P and B doped silica glass (GeBPSG). The ratio of the Ge, P, and B dopants is configured to reduce the formation of crystallization areas within the top clad layer and maintain a constant refractive index within the top clad layer across an anneal temperature range. A thermal anneal process for the top clad layer can be a temperature within a range of 950C to 1050C.

Abstract: A planar optical device is formed on a substrate. The device comprises an array of waveguide cores which guide optical radiation. A cladding layer is formed contiguously with the array of waveguide cores to confine the optical radiation to the array of waveguide cores. At least one of the array of waveguide cores and cladding layer is an inorganic-organic hybrid material that comprises 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 moieties. This material can be designed with an index of refraction between 1.4 and 1.55 and can be deposited rapidly to thicknesses of up to 40 microns. In accordance with another embodiment of the invention, a method for forming a planar optical device obviates the need for a lithographic process.

Abstract: A method of forming an optical component is disclosed. The method includes forming a first medium on a base. The base has one or more pockets defined in a side of the base. The first medium is formed on the base such that the first medium is positioned over the one or more pockets. The method also includes converting at least a portion of the first medium to a light transmitting medium.

Abstract: Devices and methods for the vapor deposition of amorphous, silicon-containing thin films using vapors comprised of deuterated species. Thin films grown on a substrate wafer by this method contain deuterium but little to no hydrogen. Optical devices comprised of optical waveguides formed using this method have significantly reduced optical absorption or loss in the near-infrared optical spectrum commonly used for optical communications, compared to the loss in waveguides formed in thin films grown using conventional vapor deposition techniques with hydrogen containing precursors. In one variation, the optical devices are formed on a silicon-oxide layer that is formed on a substrate, such as a silicon substrate. The optical devices of some variations are of the chemical species SiOxNy:D. Since the method of formation requires no annealing, the thin films can be grown on electronic and optical devices or portions thereof without damaging those devices.

Abstract: Methods of forming optical filament circuit patterns with planar and non-planar portions are provided. An optical filament circuit pattern is scribed by moving a filament guide and a substrate relative to one another at a speed between about 110 inches/minute and about 190 inches/minute, and dispensing an optical filament on, or in the vicinity of, a surface of the substrate. The filament or the substrate or both have adhesive surface(s). The adhesive surface is capable of being adhesively actuated by application of energy. Energy is applied simultaneous with, or subsequent to, scribing. Preferably, ultrasound energy is applied having an output power between about 2.0 watts and about 3.5 watts while applying a pressure to the filament between about 1.177 Newtons and about 1.324 Newtons. A portion of the filament circuit pattern is planar and another portion is non-planar. The non-planar portion traverses but does not contact or adhere to a pre-selected area of the substrate.

Abstract: The crosstalk characteristics of an arrayed waveguide grating or the like are improved. One or more of substrates are placed at a circumferential position centering the table rotational center C on a turntable that rotates at a constant angular speed of rotation &ohgr; and the turntable is rotated. A burner is moved to and fro in the radial direction of the turntable between positions r1 and r2 in the radial direction of the turntable and is reciprocated across the substrates. A material gas of glass, an oxygen gas and a hydrogen gas are passed through the burner to generate a hydrolysis reaction of the material gas in a hydrogen oxygen flame and an under cladding glass particle, a core glass particle and an over cladding particle are sequentially deposited on the substrates to form an optical waveguide part.

Abstract: A method of depositing a core layer for an optical waveguide structure of a planar lightwave circuit. A GePSG core for an optical waveguide structure of a planar lightwave circuit is fabricated such that the optical core comprises doped silica glass, wherein the dopant includes Ge and P. In depositing a core layer from which the optical core is formed, two separate doping gasses (e.g., GeH4 and PH3) are added during the PECVD process to make Ge and P doped silica glass (GePSG). The ratio of the Ge dopant and the P dopant is configured to maintain a constant refractive index within the core layer across an anneal temperature range and to reduce a formation of bubbles within the core layer. The ratio of the Ge dopant and the P dopant is also configured to reduce refractive index birefringence within the core layer across an anneal temperature range. A thermal anneal process for the core layer can be a temperature within a range of 900 C. to 1200 C.

Abstract: A method for manufacturing an optical device with a defined total device stress and a there-from resulting defined birefringence and a therefrom resulting defined optical polarization dependence is disclosed. The method comprises a first step of providing a lower cladding layer of an amorphous material, preferably based on SiO2, that may be doped with elements like Boron and/or Phosphorous with a first refractive index and a second step of providing above the lower cladding layer an upper cladding layer of an amorphous material, preferably based on SiO2, that may be doped with elements like Boron and/or Phosphorous with a second refractive index, and being manufactured from a material which is tunable in its stress.

Abstract: An optical waveguide device comprises at least one Y-junction integrated on a planar substrate. The junction comprises a first (1), a second (3) and a third (4) optical waveguide extending on the said substrate, and a transition portion (2), in which the second and third waveguides branch from the first waveguide, comprising a truncation (5) of predetermined width. At the position of the truncation, the width of the first waveguide is less than the sum of widths of the second waveguide, the third waveguide and the truncation. The first optical waveguide extends into the transition portion up to the bifurcation with its width essentially constant.

Abstract: An optical waveguide apparatus comprises a substrate (1), a patterned waveguide as a core (4), and an upper cladding layer (10) formed on the substrate. The core is surrounded by a cladding comprising the substrate as a lower cladding layer and the upper cladding layer and smaller in refractive index than the core. The core and the cladding are integrally coupled to each other in a manner such that temperature-dependent expansion or contraction is performed substantially in accordance the characteristic of the cladding. The core and the cladding are made of materials selected so that the variation in optical path length according to the temperature-dependent expansion or contraction of the cladding is canceled by the variation in optical path length according to temperature-dependent variation in refractive index of the core.

Abstract: A method for manufacturing an optical device with a defined total device stress and a therefrom resulting defined birefringence and a therefrom resulting defined optical polarization dependence is disclosed. In a preferred embodiment, a lower cladding layer of an amorphous material with a first refractive index is provided and above that an upper cladding layer of an amorphous material with a second refractive index, which latter is manufactured from a material which is tunable in its stress. Between the lower and upper cladding layer an optical waveguide core is manufactured comprising an amorphous material having a third refractive index which is larger than the first and second refractive index. The optical waveguide core is thermally annealed, after which it has a defined waveguide core stress. The upper cladding layer is manufactured to have a cladding layer stress that together with the waveguide core stress results in the total device stress.

Abstract: A method for performing high aspect ratio gap fill during planar lightwave circuit top clad deposition. A plurality of waveguide cores are formed on a substrate, the waveguide cores having a plurality of gaps there between. A cladding layer is formed over the waveguide cores and the substrate using a high-density plasma deposition process. The refractive index of the waveguide cores are controlled by using a dopant to be higher than the refractive of the cladding layer. An anneal process is performed on the cladding layer after the high-density plasma deposition process. The gaps between the waveguide cores can be smaller than 2 microns. The aspect ratio of the gaps between the waveguide cores can be greater than 3. The high-density plasma deposition process provides a very high purity USG (undoped silica glass) and BPSG (Boron Phosphorous silica glass) layers having a uniform refractive index.

Abstract: A buffer layer and an optical waveguide layer are formed on a single crystal substrate. A ridge type channel optical waveguide is formed at the optical waveguide layer along a longitudinal direction of the single crystal substrate. A cladding layer having a refractive index smaller than that of the optical waveguide layer and having a width substantially the same as that of the channel optical waveguide and having a thickness which increases in a tapered manner toward an end surface, is formed above both of a light entering end portion and a light exiting end portion of the channel optical waveguide. By the cladding layer, a mode field diameter in a direction orthogonal to a substrate surface can be enlarged, and a coupling loss with an optical fiber can be greatly reduced. Further, loss due to mode mismatching can be prevented by a light confining effect.

Abstract: An optical component comprising one or more optical elements (35′) aligned with the end(s) of one or more waveguides (25′) is fabricated by a process in which, first of all, a doped silica core layer (20) is deposited on a substrate (10) (or on a buffer layer on the substrate), and subsequently a partial overclad layer (30A) typically 1-5 &mgr;m thick is deposited on the core layer. The partial overclad layer and core layer are patterned and etched so as simultaneously to define the optical element(s) and the waveguide core(s). Afterwards, the overclad is completed by depositing a further overclad layer (30B). In the case of application of this fabrication method to a grating-based NBWDM device, the metallisation of the grating can precede or follow the deposition of the second overclad portion (30B). In either case, low-temperature deposition processes are required for deposition of this second overclad portion.

Abstract: A laser processing method for removing glass by melting, evaporation or ablation from sheet-like glass substrate for forming microscopic concavities and convexities. Diffraction grating and planar microlens array obtained thereby.

Abstract: Disclosed is a method of fabricating an optical fiber preform using a modified chemical vapor deposition method and a nonlinear optical fiber fabricated using the method, in which an impurity component is doped after both ends of a quartz glass tube are partially collapsed, so that an impurity doping process can be stably executed and the doped quantity of the impurity component can be increased. The method comprises the steps of: forming a cladding layer and a core layer in a quartz glass tube; partially sintering the core layer; partially shrinking both ends of the quartz glass tube, in which the cladding layer and the core layer partially sintered are formed; and doping a sintered portion of the core layer with an impurity component, so that the optical fiber preform fabricated has a predetermined function.

Abstract: There is disclosed a method for producing an optical waveguide substrate at least comprising a step of forming a silica film to be an optical waveguide having a thickness of 5 &mgr;m or more on a surface of a substrate by oxidizing a silicon substrate wherein the oxide film is formed by forming an oxide film having a thickness of 0.3 &mgr;m or more on the silicon substrate first, and then oxidizing the silicon substrate in an oxidizing atmosphere heated at 1000° C. or higher to form a remaining oxide film, and also disclosed an optical waveguide substrate produced by the method. There can be provided a method for producing an optical waveguide substrate comprising oxidizing a silicon substrate to a relatively deep part wherein particles generated due to exfoliation and oxidation of silicon atoms are quite few on the silica film, and thus a high quality optical waveguide substrate is produced, and also provided an optical waveguide substrate produced by the method.

Abstract: The present invention provides a method for producing low flow rates of feedstock vapors used in the manufacture of silica glass. The method includes the steps of providing a constant flow of a liquid feedstock, mixing the flow of the liquid feedstock with an injector gas, expelling the mixture of liquid feedstock and inert gas from an injector orifice into a vaporizer chamber, flowing a carrier gas into the vaporizer chamber and through the mixture of liquid feedstock and injector gas, and vaporizing the liquid feedstock in the vaporizer chamber. The present invention is useful in the fabrication of planar silica waveguides.

Abstract: According to the present invention, which provides a optical waveguide element achieving high performance and high yield, that makes it possible to form a complex light-wave circuit structure without requiring a larger mounting area and a optical waveguide element manufacturing method, a optical waveguide element 100 is provided with an Si substrate 102 and a first light-wave circuit layer 112 and a second light-wave circuit layer 120 sequentially laminated on the substrate 102. At the first light-wave circuit layer 112, a first optical waveguide structure constituted of a first clad layer 104 formed toward the substrate 102, a first core portion 108 and a second clad layer 110 formed toward the second light-wave circuit layer 120 is achieved. In addition, at the second light-wave circuit layer 120, a second optical waveguide structure constituted of a second core portion 116 and a third clad layer 118 at the second light-wave circuit layer 120 is achieved.

Abstract: A waveguide having an angled surface is created by depositing an optical core material onto a substrate having two levels. In one embodiment, a high density plasma deposition may be used to deposit the optical core material.

Abstract: An ultrathin optical panel, and a method of producing an ultrathin optical panel, are disclosed, including stacking a plurality of glass sheets, which sheets may be coated With a transparent cladding substance or may be uncoated, fastening together the plurality of stacked coated glass sheets using an epoxy or ultraviolet adhesive, applying uniform pressure to the stack, curing the stack, sawing the stack to form an inlet face on a side of the stack and an outlet face on an opposed side of the stack, bonding a coupler to the inlet face of the stack, and fastening the stack, having the coupler bonded thereto, within a rectangular housing having an open front which is aligned with the outlet face, the rectangular housing having therein a light generator which is optically aligned with the coupler. The light generator is preferably placed parallel to and proximate with the inlet face, thereby allowing for a reduction in the depth of the housing.

Abstract: There is disclosed a silica optical waveguide which comprises a silicon substrate, a lower clad film consisting of silica glass formed on the substrate, a core part for propagating light consisting of silica glass formed on the lower clad film, and an upper clad film consisting of silica glass with which the core part is buried, wherein the above-mentioned lower clad film comprises two layers of a lower first silica glass clad film formed by thermally oxidizing the silicon substrate and a lower second silica glass clad film consisting of a silica glass deposited film, and a method for producing it. There can be provided an optical waveguide wherein incline or deformation of the core part, warp of a substrate, defects such as a crack or the like are not generated during the high temperature treatment, in order to produce a silica optical waveguide which has excellent circuit characteristics in the reproducibility of optical-waveguide type devices, such as a directional coupler, and a method for producing it.

Abstract: There is disclosed a method of constructing photosensitive waveguides on silicon wafers through the utilization of a Plasma Enhanced Vapor Deposition (PECVD) system. The deposition is utilized to vary the refractive index of resulting structures when they have been subject to Ultra Violet (UV) post processing.

Abstract: The present invention provides a method for reducing the density of sites on the surface of fused silica optics that are prone to the initiation of laser-induced damage, resulting in optics which have far fewer catastrophic defects and are better capable of resisting optical deterioration upon exposure for a long period of time to a high-power laser beam having a wavelength of about 360 nm or less. The initiation of laser-induced damage is reduced by conditioning the optic at low fluences below levels that normally lead to catastrophic growth of damage. When the optic is then irradiated at its high fluence design limit, the concentration of catastrophic damage sites that form on the surface of the optic is greatly reduced.

Abstract: A process for producing a waveguide, wherein a first layer is deposited on a silicon or glass substrate, a core structure is subsequently structured, and the core structure is protected by a protective layer. Prior to each step for depositing a new layer, the layer that has just been applied is fluorinated.

Abstract: An optical waveguide substrate, which has less particles or concave pits caused by Oxidation Induced Stacking Fault on the quartz film when oxidizing the surface of the silicon substrate relatively thickly and forming on its surface a quartz film to become an optical waveguide, is manufactured. The making method of the optical waveguide substrate comprises a step of exposing a silicon substrate to an atmosphere of oxidizing gas while heating to form a quartz film on the surface thereof for an optical waveguide, characterized in that a density of Oxygen contained in said silicon substrate is 24 ppma at maximum.

Abstract: An optical waveguide which can suppress adjacent crosstalk even when wavelength intervals to be multiplexed/demultiplexed are narrow. A lower clad film and a core film are deposited and formed on a substrate (11) by flame hydrolysis deposition, and they are consolidated, whereupon the core film is processed into a waveguide pattern. The waveguide pattern is formed by successively connecting at least one optical input waveguide (12), a first slab waveguide (13), an arrayed waveguide (14) consisting of a plurality of channel waveguides (14a) arranged side by side and having lengths different from one another, a second slab waveguide (15), and a plurality of light output waveguides (16) arranged side by side. The waveguides arranged side by side are at intervals from one another. An upper clad film covering the waveguide pattern is deposited and formed by flame hydrolysis deposition, and it is thereafter consolidated.

Abstract: The same mask pattern is used as an etching mask in defining the horizontal location of micro-machined (etched) features at the substrate surface of an optical device relative to the waveguide cores also at the substrate surface of the optical device. Exemplary micro-machined features include grooves, recesses and inclined surfaces formed in the substrate surface for any of a variety of purposes. The accurate horizontal positioning of these features relative to the integrated waveguide cores fosters accurate optical coupling between the integrated waveguide cores and external and/or internal components.

Abstract: A silica glass is provided for use in an optical system processing an excimer laser beam. The silica glass has a molecular hydrogen concentration of about 5×1018 molecules/cm3 or less and is substantially free from defects which become precursors susceptible to an one-photon absorption process and a two-photon absorption process upon irradiation of the excimer laser beam to the silica glass.

Abstract: A first layer to be processed later into a core is formed on a substrate. Next on the first layer, a mask layer and an alignment marker are formed within a core forming area and an alignment marker forming area, respectively. The alignment marker, which is used as a marker for groove processing, is covered with a protective layer. The protective layer is made so as to have a width larger than that of the alignment marker, and is made of an optically transparent material. The first layer is etched while being masked with the mask and protective layers. The mask layer is then removed to thereby leave a core. The structure thus obtained by the above processes is entirely covered with a second layer which later functions as a clad. Detection of the alignment marker is effected by optically sensing the edge thereof. The conventional problem is thus successfully solved that the edge of the alignment marker cannot be detected and thus the alignment for the groove processing remains impractical.

Abstract: A silicon surface oxidation device utilizes a steam generator in which heated water is barely in contact with the members of the device, steam with no contamination is efficiently generated, and the silicon surface can be oxidized through relatively large thickness by using a steam oxidation method which is simple and high in safety. The steam generator has a feed port for pure water which flows along a surface in a chamber, an oscillator for oscillating a microwave toward the surface, a steam exit port for sending out the steam of the pure water generated from the surface by the microwave, and a discharge port for the pure water flowing along the surface. A heating furnace is connected to the steam exit port, and silicon placed in the heating furnace is oxidized by the steam generated by the microwave.

Abstract: A technique is described for the formation of nano and micro-scale patterns and optical wave-guides, by using Bipolar Electrochemistry. Atoms are deposited or removed from a surface by creating and moving ions into or out of a medium by the use of electric fields, currents, and induced surface charges. To improve the deposition process, lasers, electron, and ion lenses can be positioned over the surface being deposited to further define the pattern being created. This technique does not harm the surface or crystal lattice of the substrate being deposited on and is powerful enough to transport dopants completely through a substrate. The technique can be used to expose electron beam activated resist which can be used in traditional fabrication processes or to create wave-guides connecting separate optical or electro-optical devices together. As a result smaller and newer types of integrated circuits, electronic devices, and micro machines can be fabricated.

Abstract: A silica based optical waveguide is described, comprising a substrate, a core waveguide formed thereon, and an over cladding part comprising a silica based glass with a refractive index lowering dopant and a refractive index increasing dopant added, formed on the substrate so as to cover the core waveguide, wherein a segregation layer with a higher concentration of the refractive index increasing dopant is formed in a part of the over cladding part in contact with the substrate and the core waveguide such that at least a part of the refractive index increase in the segregation layer provided by the refractive index increasing dopant with respect to the part of the over cladding part other than the segregation layer is offset by decline of the refractive index by increasing the amount of the refractive index lowering dopant added in the segregation layer and/or adding another refractive index lowering dopant.

Abstract: An optical waveguide has first dielectric substance region which is formed on a surface of the crystalline silicon substrate, and has second dielectric substance region which is formed outside first dielectric substance region. First dielectric substance region is provided with a region in which a concentration of impurity elements for increasing and/or decreasing a refractive index in a direction of transmitting light is periodically increased and decreased, or provided with a corrugated structure, or wherein its width is periodically changed. Therefore, utilizing the property of thermal equilibrium, the optical waveguide has a grating which is thermally stable even at ordinary temperatures.

Abstract: In a method for spatially selectively increasing the refractive index in a glass layer which has been produced by flame hydrolysis deposition of a hydrolytic glass initial product on a base and subsequent sintering of the glass initial product, no measures are taken to increase the photosensitivity. Instead, heat is supplied where the refractive index of the glass is to be increased. It has been shown that this results in a densification of the sintered glass accompanied by an increase in the refractive index. The chemical composition of the thus treated regions is the same as that of the untreated regions.

Abstract: A method for fabricating an optical waveguide, comprising the following steps. That is, forming an optical waveguide on surface of a substrate via an atmospheric pressure chemical vapor deposition (AP-CVD) method using a silica raw material containing an organic material, and irradiating ultraviolet light on at least a portion of that optical waveguide. The refractive index of the portion of the optical waveguide irradiated with ultraviolet light increases. Since changing the refractive index in this way enables the formation of a diffraction grating, it is possible to manufacture optical filters and wavelength dispersion devices.

Abstract: Disclosed is an optical waveguide fiber having a compressive outer layer that includes TiO2 in the SiO2 matrix glass. The compressive outer layer includes crystalline structures containing TiO2 that are predominately rutile. Also disclosed is a method for making an optical waveguide fiber having a compressive outer layer. The compressive outer layer can contain an additional metal oxide that is preferentially lost from the outer layer, instead of the TiO2, during the drying and consolidation step.

Abstract: A method for the manufacture of optical components, at least one three-dimensional optical waveguide structure being produced in a light-sensitive substrate by locally subjecting the substrate to an exposure so that a difference in refractive index between the substrate and the at least one optical waveguide structure is created. Provision is made for an exposure to occur at least twice, at different angles of incidence for the light perpendicular to a light wave propagation direction of the optical waveguide structure; the substrate surrounding what will later be the optical waveguide structure thereby experiences a diminution in refractive index, the optical waveguide structure being defined using a mask.

Abstract: An optical waveguide device for loss absorption, and a fabrication method thereof, are provided. The optical waveguide device for loss absorption includes: a substrate of a predetermined material; a lower cladding formed on the substrate; an optical waveguide formed on the lower cladding, and formed of a material having a refractive index greater than a refractive index of the lower cladding; an upper cladding formed so as to completely cover the optical waveguide; and an absorption layer formed of a material having refractive index greater than a refractive index of the upper cladding, and formed on the upper cladding to a thickness which can absorb a reflected or radiated optical signal. As described above, an absorption layer capable of absorbing light is formed in the waveguide device upon fabricating the optical waveguide, thus minimizing or removing loss due to reflection and radiation of an optical signal.

Abstract: A glass 1 is irradiated with a focused pulsed laser beam 2 having a peak power density of 10.sup.5 W/cm.sup.2 or more and a repetition rate of 10 KHz or more. The glass 1 irradiated with the laser beam 2 changes its refractive index at the focal point 4. During the laser beam irradiation, the glass 1 is continuously moved with respect to the focal point of the pulsed laser beam 2 or continuously scanned with the focused laser beam 2, so as to form the refractive index changed region (i.e. an optical waveguide 5) with a predetermined pattern. The glass 1 in which the optical waveguide 5 will be formed may be any kind of glass having high transparency.

Abstract: An optical waveguide device is provided with a core formed on a substrate and a clad layer. A low-temperature film-forming method, such as the CVD or PVD method, is used in a core forming process for forming the core and a clad forming process for forming the clad layer. The surface of the clad layer is coated with a protective film of chrome or the like in a protective film forming process that is carried out after the clad forming process. In a heating/pressurizing process that is carried out after the protective film forming process, the clad layer is heated and pressurized from its outside by the HIP (hot isostatic pressing) method. This heating/pressurizing process substantially eliminates voids in the clad layer and the like, and enhances or improves the density of a buffer layer, core, and upper clad layer and the transparency of the core layer. The protective film is removed by etching or the like in a removing process.

Abstract: A planar waveguide structure has, supported on a lower refractive index buffer layer (5), a pair of optical cores (1, 2) that, over at least a portion of their length, are closely spaced. These cores are covered with a layer (6) of cladding material comprising boron and phosphorus doped silica glass deposited by PECVD as a succession of individually annealed layers in order to minimize the incidence of voids in the deposit between the cores.

Abstract: Annealing a planar wave guide layer is critical because small structural imperfections lead to optical problems. Chemical vapor deposition of the layer tends to leave gaseous substances bonded to the deposit, which on being driven off by initial annealing warm-ups leave cavities requiring densification. Traditional annealing methods take several hours. This invention proposes a rapid heating of the layer to a temperature below the flow temperature, maintaining this temperature for about 30 to 300 seconds, then rapidly heating up further to a temperature close to or above the flow temperature, maintaining this temperature for about 30 to 300 seconds, then allowing the substrate and layer to cool rapidly to room temperature.