Abstract: A method and an apparatus for bonding optical disk substrates, includes placing a pair of optical disk substrates on a stage while securing a height difference at an upper face of the stage loading the substrates between an upper face at a side of a center of the substrates and an upper face at a side of an outer circumference of the substrates. The method and the apparatus also includes photosetting the adhesive layer on the stage by irradiating a setting light to the substrate pair, thereby photosetting the adhesive layer and bonding the substrates.

Abstract: Fiber material and cooking liquor are introduced at the top of the digester and pulp is discharged from the bottom of the digester, via a line in which the pulp is maintained at substantially the same pressure level, to a pressurized wash. More than 50% of the used cooking liquor (black liquor) which is extracted from the system in total is extracted from the wash filtrate of the pressurized wash. At the same time a small portion of the wash filtrate is also to be recirculated to the bottom of the digester as dilution liquid. The pressurized wash is regulated so that a high temperature is maintained in the wash filtrate. The extraction is regulated so that a net co-current flow is established at the bottom of the digester.

Abstract: A method and device for bleaching chemical paper pulp or dissolving wood pulp, which has been cooked and delignified without employing chlorine-containing chemicals, comprising a bleaching sequence which comprises optionally a first stage comprising a chelation treatment step; a second stage comprising a first peroxide treatment stage, wherein said first peroxide treatment stage is a delignifying peroxide treatment stage in which the amount of peroxide is less than 12 kilo/bone dry metric tons; a third stage comprising an acidic delignifying treatment stage, following said second stage and including a wash, and a fourth stage comprising a second peroxide treatment stage, following said third stage and including a wash, wherein said second peroxide treatment stage is a bleaching peroxide treatment, in which the amount of peroxide exceeds 3 kilo/bone dry metric tons and exceeds the amount of peroxide employed in said second step.

Abstract: (Co)poly-&agr;-hydroxyacrylic-acid-based polymers (P), optionally in lactonized form or in salt form, optionally as Mg-complexes, and which are characterized by a content in carbohydrate units and 2-hydroxy-2-carboxyethylene-1,2 monomer units, are suitable as biologically degradable, alkali-resistant stabilizers for peroxide bleaching agents.

Abstract: Antifoam formulations contain a siloxane antifoam and a polyether/polysiloxane copolymer of the general formula (R2R*SiO)2(RR′SiO)x(R2SiO)y(RR″SiO)2  (I) wherein R* is either R, R′, or R″, and wherein R′ is R1O—(CH2CH2O)a[CH2CH(CH3)O]b[CH2CH(CH2CH3)O]c—R2—  (R′) and wherein R″ is —R2—O—(CH2CH2O)d[CH2CH(CH3)O]e[CH2CH(CH2CH3)O]f—R2—  (R″) wherein R, R1, R2, a, b, c, d, e, f, x, y, and z are defined herein.

Abstract: A method and apparatus treat fiber based material so as to reduce the loss of mineral fractions in the treatment of broke in paper production. Broke is a reusable raw material from a paper machine that contains mineral fractions which are desirably returned to the process as a raw material. The material containing minerals is dispersed into broke pulp, which is fractionated, and the accepts from the fractionation are returned to the paper manufacturing process providing for efficient and economical recovery of the minerals in broke. The mineral fraction provided in the rejects from the fractionation is treated separately before it is reused as filler or coating material in the production of paper or board.

Abstract: A method and apparatus for manipulating dryer steam pressure in a paper machine during grade change, wherein change in moisture percentage is determined from a change in production amount during grade change, dryer stream pressure is manipulated so as to cancel the change in the moisture percentage, and production amount during grade change is calculated from basis weight and machine speed before and after grade change, whereby moisture percentage is kept constant during grade chagne so that sheet breaks are avoided and downtime is reduced.

Abstract: A headbox for use in a water felting process includes a housing and two rotating horizontal distribution rolls. The housing has curved sections shaped to conform to the outer cylindrical surface of the distribution rolls, wherein the curved section is closely spaced to a portion of the outer cylindrical surface of both distribution rolls.

Abstract: A method of producing a pulp molded article comprising a papermaking step in which a pulp slurry is fed to the surface of a papermaking mold having suction paths, and water contained in the pulp slurry is sucked through the suction paths whereby the pulp is deposited on the surface to form a wet preform, and a dewatering step in which the wet preform is dewatered, wherein the temperature of the fed pulp slurry is raised while the pulp is being deposited on the surface.

Abstract: Transfer belt for a paper machine, comprising a base structure (2) and a fiber batt layer (3) attached to the base structure and facing the fiber web. At least the fiber batt layer side of the belt is provided with a polymer matrix (4) impregnating the fiber batt layer (3). According to the idea of the invention, the transfer belt fiber batt layer comprises at least two fibers with different surface properties, the transfer belt surface facing the fiber web being thus provided with hydrophilic and, correspondingly, hydrophobic areas. The fibers in the fiber batt layer may differ from one another with regard to their polarity, hydrophilicity, electric charge, surface energy, friction properties, degree of fineness or porosity.

Abstract: Suction box in a paper machine including a vacuum chamber, a deck or a number of substantially U-section holders open toward a wire and ribs arranged in the deck or the holders so that they can be loaded against the wire. At least in a running situation, the deck of the suction box is curved or the ribs are arranged to provide a curve run of the wire so that the wire tension of the curved run over the deck or ribs serves to lower a normal force which is produced by the vacuum present in the suction box and which is effective between the wire and the deck or ribs.

Abstract: The method and system of the present invention is designed to minimize exergy consumption consistent with a given level of product purity. For example, in a distillation system, the design employs a plurality of thermostatted trays which are maintained at a sequence of temperatures specified by finding the optimal control for an irreversible thermodynamic process. The specified temperatures at each tray are achieved with the help of a tandem heat pump which works over the range of required temperatures and which delivers the specified heat demands.

Abstract: A process for the work up of a reaction mixture obtained from the preparation of diaryl carbonate by direct carbonylation of aromatic hydroxy compounds is disclosed. The process entails obtaining a reaction mixture that contains diaryl carbonate, aromatic hydroxy compound, water, base and quaternary salt, separating the mixture in a distillation apparatus having only one theoretical separation stage into a liquid phase and a gas phase and recycling the liquid phase without further work up to the reaction step of the direct carbonylation.

Abstract: A process for the distillative recovery of high purity monoethylene glycol from the hydrolysis, product of ethylene oxide by pressure dewatering, preferably in a battery, vacuum dewatering and subsequent purifying distillation, wherein during the vacuum dewatering an aqueous stream is withdrawn which contains-monoethylene glycol in a concentration below 1% by weight, preferably below 0.1% by weight, medium boilers and low boilers. The withdrawn aqueous stream is, optionally after further workup, removed from the system.

Abstract: A method for isolating 32 from a crude mixture containing HCl and an azeotropic mixture of 32 and HF is provided without the need to isolate any HF azeotrope.

Abstract: The present invention relates to novel calix pyrroles and a process for synthesis of calix (4) pyrroles by reacting pyrrole with cyclic or acyclic ketones in dichloro methane (DCM) solvent over molecular sieve catalysts which provides an eco-friendly, more economical and selective heterogeneous method.

Abstract: A sputtering apparatus for depositing layers of material onto a substrate includes a vacuum chamber, a first target and a second target positioned within the vacuum chamber. A source of power is placed in electrical communication with the first target and the second target. A switch alternately connects the source of power between the first target and the second target. The first target and the second target are different materials. The switch connects power to the first target when the transport mechanism positions the substrate near the first target and the switch connects power to the second target when the transport mechanism positions the substrate closer to the second target.

Abstract: Provided are a method of forming a magnetic layer pattern and a method of manufacturing a thin film magnetic head, which can reduce the number of manufacturing steps and thus reduce the manufacturing time. A precursory nonmagnetic layer and a precursory bottom pole layer are formed in this sequence so as to cover a frame pattern formed on an underlayer (a top shield layer) and having an opening. Then, the precursory nonmagnetic layer and the precursory bottom pole layer are patterned by polishing the overall surface by CMP until at least the frame pattern is exposed, and thus a nonmagnetic layer and a bottom pole are selectively formed. The number of manufacturing steps can be reduced and thus the manufacturing time can be reduced, as compared to the case of forming the nonmagnetic layer and the bottom pole without forming the frame pattern.

Abstract: The present disclosure pertains to a method of filling features (typically trenches or vias) on a semiconductor workpiece surface with copper using sputtering techniques previously believed incapable of achieving a copper fill. In particular, when the feature is to be filled with a single, continuous application of sputtered copper, the surface of the substrate to which the sputtered copper is applied should range between about 200° C. and about 600° C.; preferably the surface temperature of the substrate ranges between about 300° C. and about 500° C. When the feature is to be filled using a thin wetting layer of copper, followed by a fill layer of copper, the wetting layer may be applied by sputtering techniques or by other methods such as evaporation or CVD, while the fill layer of copper is applied using sputtering techniques. The thin wetting layer of copper is applied at a substrate surface temperature ranging between about 20° C. to about 250° C.

Abstract: An electrical field between a positive anode and a negative target in a cavity and a magnetic field in the cavity cause electrons from the target to ionize neutral gas (e.g. argon) atoms in the cavity. The ions cause the target to release sputtered atoms (e.g. aluminum) for deposition on a substrate. A shield between the target and the substrate inhibits charged particle movement to the substrate. The anode potential may be positive, and the shield and the magnetic members may be grounded, to obtain electron movement to the anode, thereby inhibiting the heating of the shield and the magnetic members by electron impingement. The anode may be water cooled. The magnitude of the positive anode voltage relative to the target voltage provides selectively for (a) a uniform thickness of sputtered atoms on the walls of a groove in the substrate or (b) a filling of the groove by the sputtered atoms and a uniform thickness of deposition on the substrate surface including the filled groove.

Abstract: An aluminum alloy sputter target having a sputter target face for sputtering the sputter target is provided. The sputter target face has a textured-metastable grain structure. The textured-metastable grain structure has a grain orientation ratio of at least 35 percent (200) orientation. The textured-metastable grain structure is stable during sputtering of the sputter target. The textured-metastable grain structure has a grain size of less than 5 &mgr;m. The method forms aluminum alloy sputter targets by first cooling an aluminum alloy target blank to a temperature of less than −50° C. Then deforming the cooled aluminum alloy target blank introduces plastic strain into the target blank and reduces the grain size of the grains to form a textured-metastable grain structure. Finally, finishing the aluminum alloy target blank forms a finished sputter target that maintains the textured-metastable grain structure of the finished sputter target.

Abstract: Novel polymeric transition metal complexes of iron, cobalt, ruthenium, osmium, and vanadium are described. The polymeric transition metal complexes can be electron transfer mediators in enzyme-based electrochemical sensors. In such instances, transition metal complexes accept electrons from, or transfer electrons to, enzymes at a high rate and also exchange electrons rapidly with the sensor.

Abstract: Novel transition metal complexes of iron, cobalt, ruthenium, osmium, and vanadium are described. The transition metal complexes can be used as redox mediators in enzyme based electrochemical sensors. In such instances, transition metal complexes accept electrons from, or transfer electrons to, enzymes at a high rate and also exchange electrons rapidly with the sensor. The transition metal complexes include at least one substituted or unsubstituted biimidazole ligand and may further include a second substituted or unsubstituted biimidazole ligand or a substituted or unsubstituted bipyridine or pyridylimidazole ligand. Transition metal complexes attached to polymeric backbones are also described.

Abstract: A mixed potential electrochemical sensor for the detection of gases has a ceria-based electrolyte with a surface for exposing to the gases to be detected, and with a reference wire electrode and a sensing wire electrode extending through the surface and fixed within the electrolyte as the electrolyte is compressed and sintered. The electrochemical sensor is formed by placing a wire reference electrode and a wire sensing electrode in a die, where each electrode has a first compressed planar section and a second section depending from the first section with the second section of each electrode extending axially within the die. The die is filled with an oxide-electrolyte powder and the powder is pressed within the die with the wire electrodes. The wire-electrodes and the pressed oxide-electrolyte powder are sintered to form a ceramic electrolyte base with a reference wire electrode and a sensing wire electrode depending therefrom.

Abstract: There is disclosed an electrode apparatus, which comprises an electrode (1) composed of a conductor through which perforations (2) are formed from a surface to a backing surface, wherein when the conductor is maintained at an electric potential sufficient to cause an oxidation or reduction reaction to occur in substances to be treated (3) of a solution entered from an inlet of the perforation and passed through inside the perforation, the substances to be treated are captured or rendered harmless by their oxidation or reduction reaction inside the perforation, and the solution whose concentration is lowered is diffused from an outlet of the perforations.

Abstract: Disclosed is an improved electrolyte formulation for the electrodeposition of copper onto electronic devices substrates and a process using the formulation. The formulation is a solution which contains copper alkanesulfonate salts and free alkanesulfonic acids and which is intended for the metallization of micron or sub-micron dimensioned trenches or vias.

Abstract: An electrochemical reaction assembly and methods of inducing electrochemical reactions, such as for deposition of materials on semiconductor substrates. The assembly and method achieve a highly uniform thickness and composition of deposition material or uniform etching or polishing on the semiconductor substrates by retaining the semiconductor substrates on a moving cathode immersed in an appropriate reaction solution wherein a wire mesh anode rotates about the moving cathode during electrochemical reaction.

Abstract: A process for increasing the yield of C10 plus hydrocarbon products from a Fischer-Tropsch plant which comprises the steps of (a) separating a Fischer-Tropsch product into a wax fraction and a condensate fraction; (b) dewaxing the wax fraction to produce a high boiling intermediate; (c) hydrofinishing the high boiling intermediate; (d) dehydrating the alcohols in the condensate fraction to convert them into olefins; (e) oligomerizing the olefins to form higher molecular weight hydrocarbons; (f) hydrofinishing the oligomerization mixture; and (g) and recovering a C10 plus hydrocarbon product from the hydrofinishing zone.

Abstract: A catalyst suitable for use in fluid catalytic cracking of petroleum feedstock in the form of particulate of crystalline zeolite having a coating on it6s surface comprising bayerite phase alumina.

Abstract: A process and apparatus are disclosed that relate generally to a process for reducing harmful or unwanted emissions during the production of asphalt, such as blue smoke. The process includes the introduction of a pump around of the wax oil fraction for re-introduction into the vacuum tower. Additional desirable features include stripping trays below the wax oil collection tray and the feed zone. The result is to produce an asphalt product that creates less blue smoke in the hot mix plant. Another desirable feature is that a product can be created that meets Performance Grade specifications with the addition of polymers or other additives.

Abstract: A self-sustaining non-biodegradable waste breakdown system has a preprocessing assembly, a heating assembly, a reaction assembly and a filtering assembly. The reaction assembly has a filtering layer to retain long chain molecules of the melted waste for continuous breakdown so as to change the long chain molecules into short chain molecules. The filtering-adjusting mechanism of the filtering assembly recycles the medium with a special concentration, viscosity and heat resistance in the reaction chamber.

Abstract: A filter device for filtering hydraulic fluid includes first and second subelements 40, 42 within a filter housing having separate inflows 20, 24 thereto for the respective subelements and a common outflow 22. The first subelement has a higher filter fineness than the second subelement. Several bypass configurations are taught and include: (i) a bypass line 28 for bypassing the second subelement by drawing fluid directly from the supply 95; (ii) a bypass valve 116 (FIG. 3) for bypassing the first subelement; and (iii) a bypass valve 151 (FIG. 5) for connecting the first subelement inflow 20 with the common outflow 22. The device is compact, has an easy-to-service arrangement, and ensures protection of a hydraulic pump and highly stressed hydraulic components.

Abstract: The present invention relates to pool filters. An underdrain design is disclosed that primarily relies on a peripheral ring rather than lateral projections to transfer the water to the sand. The ends of the ring are not joined so that the ring is not closed. The ring is also bent into a helical shape which allows the ring to be screwed into an opening with a smaller diameter than that of the ring. The ring is radially slotted so that water flows radially from it in all directions both toward the center of the tank and away from the center, as well as straight up and down. Since the water transfer takes place primarily along an arc located relatively near the mid-point between the center and the perimeter of the tank, the disadvantages inherent in the concentration of the water flow at the center of the tank are eliminated.

Abstract: A method and device for removing pollution from polluted water, consisting of a rod on which are mounted an array of spaced magnesium plates and an array of spaced copper plates. The copper plates are in contact with the magnesium plates. Polluted water passing through the plates results in precipitates of the pollutants which can be mechanically removed.

Abstract: An automated analyzer for performing multiple diagnostic assays simultaneously includes multiple stations, or modules, in which discrete aspects of the assay are performed on fluid samples contained in reaction receptacles. The analyzer includes stations for automatically preparing a specimen sample, incubating the sample at prescribed temperatures for prescribed periods, preforming an analyte isolation procedure, and ascertaining the presence of a target analyte. An automated receptacle transporting system moves the reaction receptacles from one station to the next.

Abstract: A single housing includes a diluent inlet, a solution outlet, and a plurality of discrete reagent beds comprising at least one reagent in dry form, wherein the reagent is present in the discrete reagent bed in a proportion sufficient for production of a complete hemodialysate solution.

Abstract: An oil filter including a housing, a first oil filter element, a second oil filter element disposed circumferentially about a length of the first oil filter capable of filtering particles of a smaller size than the first oil filter element. A first oil filter inlet is disposed at a bottom portion of the housing for providing oil to be filtered to an outside surface of the first oil filter element, and a second oil filter inlet is disposed at the bottom portion of the housing and surrounding the first oil inlet for providing oil to be filtered to a bottom surface of the second oil filter element. A fluid communication path extends from a top surface of the second oil filter element into the first oil filter element such that oil filtered through the second oil filter element is mixed with oil filtered by the first oil filter element.

Abstract: A compact, rapid upflow deep media filter for removing suspended solids from a liquid flow, which includes: a filter casing having a liquid inlet port, a liquid outlet port, and a filter bed composed of a volume of granular filter media and located between the inlet port and the outlet port; and a screen, selectably movable between a first operative position and a second operative position within the filter casing, whereat in the first operative position the screen maintains the filter bed in a packed state so as to permit filtration therethrough of a liquid flow from the inlet port to the outlet port, and whereat in the second operative position the screen does not maintain the filter bed in a packed state such that in the presence of a liquid flow from the inlet port to the outlet port the volume of filter media expands so as to enable separation therefrom of suspended solids accumulated during filtration of the liquid flow therethrough.

Abstract: A bacterial fluid filter includes a filter element supported by a backing member. The filter element and backing member are sealed, e.g., with one or more o-ring seals, in a housing to provide a filter assembly capable of filtering fluid under relatively high pressure. In one embodiment, a filter element, backing member, and seal are disposed in a removable and disposable housing that is sized to fit within a filter housing.

Abstract: A dialyzer for blood treatment includes a semipermeable membrane which is made of a hydrophobic polymer and a hydrophilic polymer, and has a water permeating performance drying of ½ or higher relative to that before drying. The dialyzer has a vitamin B12 clearance not smaller than 135 ml/min per 1.6 m2 or the amount of the hydrophilic polymer eluted from the semipermeable membrane is not higher than 10 ppm. A dialyzer for blood treatment is light-weight, easy to handle, and exhibits a reduced elution of the hydrophilic polymer procedures for producing a dialyzer containing the semipermeable membrane and a process for producing a hollow fiber membrane for use in blood treatment as described.

Abstract: A wastewater treatment system for use with a conventional septic tank, or other small-scale wastewater treatment facility, for enhancing wastewater treatment without requiring complex control or maintenance limitations. The system incorporates a plurality of primary functions that combine to oxidize, nitrify, denitrify and remove water borne total dissolved solids prior to effluent discharge. Included is a fluidized-bed reactor containing biofilm attached to carrier particulates for use in the purification of wastewater. The fluidized-bed reactor is configured to include two distinct regions, namely a “lower” aerobic region and an “upper” anoxic region, during normal operating conditions. The lower aerobic region uses aerobic facultative bacteria to oxidize Carbonaceous Biochemical Oxygen Demand (CBOD), organic (Kjeldahl) nitrogen, and ammonia while consuming the dissolved oxygen in the water.

Abstract: A wastewater treatment process that provides improved reduction of total solids through endogenous respiration while reducing biochemical oxygen demand and utilizing biological nutrient reduction. The wastewater treatment process uses an efficient aeration delivery system to drastically reduce the time needed to oxidize organic matter, and recirculates, shreds and homogenizes the organic matter and microorganisms and oxygenates the entire mass many more times than traditional systems resulting in a greater biological solids digestion rate.

Abstract: Provided is a method for washing an impurities-containing polycarbonate/organic solvent solution with an aqueous washing solution, which comprises monitoring the viscosity of the mixture dispersion of the polycarbonate/organic solvent solution and the aqueous washing solution, and controlling the blend ratio of the aqueous washing solution in the system on the basis of the relation between the phase condition and the viscosity of the mixture dispersion. In the method of washing a polycarbonate/organic solvent solution with an aqueous washing solution, the amount of the washing solution to be used is reduced, and the mixture dispersion of the two solutions is stabilized at a high level of washing efficiency. The washing method is economical in practical use.

Abstract: The invention relates to a method for the production of factor VIII:C/von Willebrand factor complex from plasma or a plasma fraction by chromatography in a cation exchanger, wherein the factor VIII:C/von Willebrand factor complex is obtained with at least 300 times the purity of the plasma and the yield of factor VIII:C and the von Willebrand factor is at least 50% in relation to cryoprecipitates or analogous plasma fractions.

Abstract: An automated blood separation method and apparatus is described that allows for the separation of multiple units of blood simultaneously. The method and apparatus reliably and quickly separates blood into its components. An auto-balancing feature within the apparatus automatically preferably compensates for the changing state of imbalance, thereby eliminating the need for additional balancing steps during the separation process. The apparatus has a rotor into which a plurality of cassettes can be inserted. The cassettes have a number of sections for the containment of the whole blood and for the separated blood components, which are contained in disposable bags. The rotor is placed into a centrifuge assembly, and the blood components are then separated and transferred to the bags in the individual sections of the cassettes. Means for including secondary separation devices such as filters is included.

Abstract: A coalescer apparatus is used in oil-water separator tanks. The coalescer includes a frame that supports coalescing plates that are inclined upwardly from the bottom of the frame member. The coalescing plates run parallel with each other and are spaced equally apart. The coalescing plates have a bottom surface that is corrugated and a top surface that is flat without corrugations. Water containing oil and solids is passed through the coalescing apparatus and separation of the oil and solids from the water occurs. The solids fall to the top flat surface of the inclined coalescing plates. The inclined flat surface cause the solids to slide down the plate and out of the coalescer.

Abstract: A three-dimensional element is fabricated from a high-temperature superconductor. The method and apparatus can fabricate, for example, a single-electron tunnel device or an intrinsic Josephson device which utilize the layer structure peculiar to the high-temperature superconductor, with machining from the side surface of a monocrystal or thin film. In the focused-ion beam etching, a substrate holder which is rotatable about 360°, is rotated, at the minimum, through an angle of about 90°, and the thin film or monocrystal on the substrate is etched from the side surface thereof so as to fabricate the element. After the thin film or monocrystal is machined from above by means of an focused-ion beam to thereby form a bridge having a junction length, the sample is rotated by about 90° (270°). Subsequently, a multi-layer current path layer is formed through side-surface machining. The junction length is accurately controlled through measurement of the current path length from an image display.

Abstract: A method is disclosed for speeding workpiece thoughput in low pressure, high temperature semiconductor processing reactor. The method includes loading a workpiece into a chamber at atmospheric pressure, bringing the chamber down to an intermediate pressure, and heating the wafer while under the intermediate pressure. The chamber is then pumped down to the operating pressure. The preferred embodiments involve single wafer plasma ashers, where a wafer is loaded onto lift pins at a position above a wafer chuck, the pressure is rapidly pumped down to about 40 Torr by rapidly opening and closing an isolation valve, and the wafer is simultaneously lowered to the heated chuck. Alternatively, the wafer can be pre-processed to remove an implanted photoresist crust at a first temperature and the chamber then backfilled to about 40 Torr for further heating to close to the chuck temperature. At 40 Torr, the heat transfer from the chuck to the wafer is relatively fast, but still slow enough to avoid thermal shock.

Abstract: A method of manufacturing a ridge-shaped 3-dimensional waveguide, has the steps of: forming a crystal film made of a second ferroelectric oxide non-linear crystal having a refractive index higher than that of a substrate made of a first ferroelectric oxide non-linear crystal on the substrate; forming a metal film on the crystal film; forming a mask by etching the metal film; and forming a ridge portion by selectively removing the crystal film through the mask by a dry etching method.

Abstract: Proposed is a method for fabricating a planar optical waveguide device having a plurality of core segments formed between a lower clad layer and an upper clad layer, in which a hot isostatic pressing process (HIP) is carried out during the fabrication process. The lower clad layer may consist of a substrate or a buffer layer formed on a substrate. Each layer may be formed either by a low-temperature film-forming process such as CVD or by the flame hydrolysis pressing process. The HIP process is also effective in eliminating voids when the core is formed in a recess of the lower clad layer. According to the tests conducted by the inventors, it was found that the HIP process can be conducted without requiring any protective layer or a gas barrier through proper selection of the condition for the HIP process, as opposed to the common belief that a protective layer or a gas barrier is essential for the HIP process.