Abstract: A SiO2—Al2O3—Li2O component-based glass material, which comprises, as basic components, SiO2: 60-63 wt %; Al2O3: 23-25 wt %; and Li2O: 4-5 wt % and, as modifying components, ZrO2: 1.5-2.5 wt %; TiO2: 0.5-2.5 wt %; MgO: 0.5-1.5 wt %; ZnO: 0.5-1.2 wt %; Na2O: 0.5-2.0 wt %; and K2O: 0.5-2.0 wt %, and further comprises any one of BaO: 0.5-1.0 wt, CaO: 1.0-2.0 wt %, and B2O3: 0.01-1.0 wt %. This can be reheat-formed in a glass state and has a low thermal expansion coefficient.

Abstract: There is provided a thermally fused integral ferrule in which a first glass substrate is at least partly unitarily combined with a second glass substrates by means of thermal fusion. The first glass substrate includes optical-fiber fixing V-shaped grooves on its side opposed to the second glass substrate, and also includes on the optical-fiber fixing V-shaped grooves in the first glass substrate, a guide section having a predetermined void between the first and second glass substrates. The thermally fused integral ferrule is manufactured by contacting the surface to be thermally fused of the first glass substrate in which the optical-fiber fixing V-shaped grooves are formed, with the surface to be thermally fused of the second glass substrate, followed by thermal fusion of the surfaces of the first and second glass substrates at a temperature of (Tg1−100) to (Tg2+150)° C.

Abstract: An optical fiber array having: a lower substrate with V-grooves formed; and an upper substrate configured by a fiber presser substrate for pressing optical fibers disposed on the V-grooves, and a coated-fiber settling substrate for settling coated fibers 13. On the coated-fiber settling substrate, a slit or a groove is formed. With this optical fiber array, damages or the like of constituents are avoided and an excellent long-term reliability is attained.

Abstract: To provide a substrate having V-shaped grooves having multi-angled V-shaped grooves in which a slant face of the V-shaped grooves has two or more angles. A cross section of the V-shaped grooves is formed so that the angle that a straight line forming a groove above a contact point of a fiber with the V-shaped grooves makes with a tangential line at the contact point is an acute angle smaller than 180 degrees. The cross section of the V-shaped grooves may be formed so that the angle that a straight line forming a groove below a contact point of a fiber with the V-shaped grooves makes with a tangential line at the contact point is an acute angle smaller than 180 degrees. The substrate having V-shaped grooves having a slant face shape with two or more angles can be manufactured by grinding a glass substrate by using a diamond grinding stone having several types of tip end angles.

Abstract: On the pressing surface of a die, a first protrusion having a substantially triangular cross section and a second protrusion having a length which is greater than a width thereof and a substantially trapezoidal cross section in planes extending through both length and width dimensions thereof are provided. By press forming, a groove with a substantially V-shaped cross section to mount an optical part, and a groove with a substantially inverse-trapezoidal cross section providing an alignment marking are formed, being inverse-transferred in correspondence with the respective protrusions on one principal surface of a glass substrate. Forming such a pattern on a glass substrate produced with a die enables alignment of the glass substrate with a mask for photolithography with high accuracy.

Abstract: A platinum thin film having a thickness of 0.01 to 5 &mgr;m is formed by means of the sputtering method on a press face of a die based on the use of a cemented carbide base material. A nickel thin film having a thickness of 0.05 to 0.5 &mgr;m and a thin film made of an alloy of platinum and iridium are allowed to intervene between the cemented carbide base material and the platinum thin film, if necessary. Alternatively, an alloy thin film having a thickness of 0.01 to 5 &mgr;m, which contains 10 to 70% by weight of iridium and 30 to 90% by weight of one or more species of metals selected from metals of the platinum group except for iridium, may be allowed to intervene between the cemented carbide base material and the platinum thin film.

Abstract: A SiO2-Al2O3-Li2O component-based glass material, which comprises, as basic components, SiO2: 60-63 wt %; Al2O3: 23-25 wt %; and Li2O: 4-5 wt % and, as modifying components, ZrO2: 1.5-2.5 wt %; TiO2: 0.5-2.5 wt %; MgO: 0.5-1.5 wt %; ZnO: 0.5-1.2 wt %; Na2O: 0.5-2.0 wt %; and K2O: 0.5-2.0 wt %, and further comprises any one of BaO: 0.5-1.0 wt, CaO: 1.0-2.0 wt %, and B2O3: 0.01-1.0 wt %. This can be reheat-formed in a glass state and has a low thermal expansion coefficient.

Abstract: There is provided a glass substrate having a V-groove portion for arranging an optical fiber core and a countersunk portion for containing an optical fiber coated portion, formed on the extension of the V-groove portion, on the surface thereof. The surface roughness of an inside side face of the countersunk portion is 1 &mgr;m or less in Rmax, or 0.2 &mgr;m or less in Ra at least at the connecting portion of the V-groove portion and the countersunk portion. The glass substrate is manufactured by a two-stage molding method in which a first molding step for forming a concave portion in the surface of a glass substrate molded body by grinding or pressing, and a second molding step for pressing the glass substrate molded body obtained by the first molding step from the top and bottom surfaces while reheating the molded body are performed.

Abstract: To provide a press mold for molding glass that is relatively less expansible than a mold material. The mold is configured so that the content volume of the mold is approximately equal to the volume of molded glass at the time of press molding, and a side face member of the mold is divided into a plurality of pieces so as to be capable of moving toward an outside but incapable of moving toward an inside. Thereby, over-tightening of mold side face can be prevented effectively, and a satisfactory molding operation can be performed by transmitting a molding pressure uniformly to a molded member without opening any mold side face.

Abstract: To provide a substrate having V-shaped grooves including: a V-groove portion having a plurality of V-grooves; a flat portion; and a stepped portion connecting the V-groove portion to the flat portion. The stepped portion is formed so as to be curved convexly toward the surface thereof. There is also provided an optical fiber array including: the substrate having V-shaped grooves; and a fiber holding substrate for holding at least fibers inserted and arranged in the V-grooves in the substrate having V-shaped grooves. A stress concentration on the fiber can be prevented and the stress can be decreased as a whole.

Abstract: A press mold for glass substrate includes an upper mold and a lower mold, and a pressure apparatus for applying pressure to the upper mold and the lower mold, for molding a plate-shaped glass substrate having a predetermined thickness between the upper mold and the lower mold. An engaging projected piece is projectingly provided on the side portion of the upper mold, an engaging projected piece supporting portion for supporting the engaging projected piece is provided on the side portion of the lower mold, and an end portion of the upper mold is formed so as to be released from the lower mold with the engaging projected piece as a rotating shaft. Variance in pressure on mold surfaces between the upper mold and lower mold is detected, and a buffer made of material having lower compressive yield strength than material constituting the lower mold is inserted between the lower mold and the pressure apparatus in a position corresponding to the mold surface portion at lower pressure.

Abstract: A press mold for glass substrate includes an upper mold and a lower mold, and a pressure apparatus for applying pressure to the upper mold and the lower mold, for molding a plate-shaped glass substrate having a predetermined thickness between the upper mold and the lower mold. An engaging projected piece is projectingly provided on the side portion of the upper mold, an engaging projected piece supporting portion for supporting the engaging projected piece is provided on the side portion of the lower mold, and an end portion of the upper mold is formed so as to be released from the lower mold with the engaging projected piece as a rotating shaft. Variance in pressure on mold surfaces between the upper mold and lower mold is detected, and a buffer made of material having lower compressive yield strength than material constituting the lower mold is inserted between the lower mold and the pressure apparatus in a position corresponding to the mold surface portion at lower pressure.

Abstract: An optical fiber array includes an upper substrate and a lower substrate in which V-shaped grooves are formed, optical fibers being inserted and arranged in the V-shaped grooves. The tips of a plurality of protruding portions formed between the plurality of V-shaped grooves are shaped like planes. The optical fiber array can prevent optical fibers from being damaged or cut while preventing substrates from being cut when the fibers are placed in V-shaped grooves for alignment.

Abstract: A heat-fused unitary ferrule includes a first glass substrate and a second glass substrate. The first glass substrate and the second glass substrate are unitarily joined by heat-fusion. A method for producing a heat-fused unitary ferrule includes the steps of: bringing a surface to be heat-fused of the first glass substrate having a groove for fixing an optical fiber into contact with a surface to be heat-fused of the second glass substrate; and subjecting the first and second glass substrates to heat-fusion at a temperature ranging from (Tg1-100).degree. C. to (Tg2+150).degree. C. (Tg1 denotes the higher glass transition temperature, and Tg2 denotes the lower glass transition temperature of the first and second glass substrates).