Abstract: An optical fiber includes: a core; and a clad which is formed so as to surround an outer circumference of the core concentrically with the core, the clad having at least an inner cladding layer adjacent to the outer circumference of the core and an outer cladding layer formed on an outer circumference of the inner cladding layer, wherein a refractive index of the outer cladding layer is ?3, and an outer circumference radius of the outer cladding layer is r3, a relationship of ?1max>?3>?2min is satisfied, a relationship of ?3??2min?0.08% is satisfied, a relationship of r1<r2<r3 is satisfied, a relationship of 0.35?r1/r2?0.55 is satisfied, a cable cut-off wavelength is less than or equal to 1260 nm, and an MFD at a wavelength of 1310 nm is 8.6 ?m to 9.2 ?m.

Abstract: An optical fiber includes: a core; and a clad which is formed so as to surround an outer circumference of the core concentrically with the core, the clad having at least an inner cladding layer adjacent to the outer circumference of the core and an outer cladding layer formed on an outer circumference of the inner cladding layer, wherein a refractive index of the outer cladding layer is ?3, and an outer circumference radius of the outer cladding layer is r3, a relationship of ?1max>?3>?2min is satisfied, a relationship of ?3??2min?0.08% is satisfied, a relationship of r1<r2<r3 is satisfied, a relationship of 0.35?r1/r2?0.55 is satisfied, a cable cut-off wavelength is less than or equal to 1260 nm, and an MFD at a wavelength of 1310 nm is 8.6 ?m to 9.2 ?m.

Abstract: There is provided a manufacturing method for an optical fiber that easily reduces transmission losses in the optical fiber. The method includes a drawing process P1 of drawing an optical fiber from an optical fiber preform 1P in a drawing furnace 110; and a slow cooling process P3 of slowly cooling the optical fiber having been drawn in the drawing process P1 in an annealing furnace 121. The temperature of the optical fiber to be delivered into the annealing furnace 121 is a temperature of 1,300° C. or more and 1,650° C. or less. The temperature of the optical fiber to be delivered out of the annealing furnace 121 is a temperature of 1,150° C. or more and 1,400° C. less.

Abstract: An optical fiber winding reel of the invention includes: a cylindrical main winding body; main flanges provided at both respective ends of the main winding body in an axis direction thereof; and an auxiliary winding body provided outside at least one of the main flanges, wherein a slit that extends toward a central axis line of a reel is formed at part in a circumferential direction of the main flange at which the auxiliary winding body is provided, and both side portions of a position of the main flange at which the slit is formed are a low rigidity region, the low rigidity region has a rigidity locally lower than that of the other portions in a direction orthogonal to a plate surface of the main flange.

Abstract: Provided is a process for producing an optical fiber including a processing process where an optical fiber work made of a glass is held by a processing apparatus for an optical fiber work to be heated and processed, wherein in the processing process, vibration caused by an abnormality of the optical fiber work in the heated state or vibration caused by an abnormality of a glass body which is a portion of the processing apparatus for an optical fiber work and is in the state where the glass body portion is heated due to the heating of the optical fiber work is detected by using an acoustic emission sensor.

Abstract: An optical fiber winding reel of the invention includes: a cylindrical main winding body; main flanges provided at both respective ends of the main winding body in an axis direction thereof; and an auxiliary winding body provided outside at least one of the main flanges, wherein a slit that extends toward a central axis line of a reel is formed at part in a circumferential direction of the main flange at which the auxiliary winding body is provided, and both side portions of a position of the main flange at which the slit is formed are a low rigidity region, the low rigidity region has a rigidity locally lower than that of the other portions in a direction orthogonal to a plate surface of the main flange.

Abstract: A method of producing optical fiber preform includes: forming a deposited layer by depositing glass particles on a periphery of a target element in a deposition mode while burning a mixed gas containing a glass source material gas, a flaming gas, and a supporting gas by use of a flaming burner; maintaining a state where the supporting gas flows at a flow velocity greater than or equal to a flow velocity at which a nozzle end of the supporting gas discharge nozzles does not glow while maintaining a pilot burner by allowing the flaming gas to flow to the seal gas discharge nozzle after a seal gas is replaced with the flaming gas in a case where a mode is changed from the deposition mode to a non-deposition mode; and replacing the flaming gas flowing to the flaming gas port with a purge gas.

Abstract: Provided is a process for producing an optical fiber including a processing process where an optical fiber work made of a glass is held by a processing apparatus for an optical fiber work to be heated and processed, wherein in the processing process, vibration caused by an abnormality of the optical fiber work in the heated state or vibration caused by an abnormality of a glass body which is a portion of the processing apparatus for an optical fiber work and is in the state where the glass body portion is heated due to the heating of the optical fiber work is detected by using an acoustic emission sensor.

Abstract: A porcelain enamel substrate (1) mounts a light emitting element in which a porcelain enamel layer (5) is coated onto a surface of a core metal (4), and a reflective cup portion (7) that has a flat bottom surface and a sloping portion that surrounds this bottom surface is provided on a light emitting element mounting surface, and an electrode (6) for energizing a light emitting element (3) is provided on the light emitting element mounting surface, and the thickness of the electrode (6) within the reflective cup portion (7) is within a range of 5 ?m to 100 ?m.

Abstract: A method of producing optical fiber preform includes: forming a deposited layer by depositing glass particles on a periphery of a target element in a deposition mode while burning a mixed gas containing a glass source material gas, a flaming gas, and a supporting gas by use of a flaming burner; maintaining a state where the supporting gas flows at a flow velocity greater than or equal to a flow velocity at which a nozzle end of the supporting gas discharge nozzles does not glow while maintaining a pilot burner by allowing the flaming gas to flow to the seal gas discharge nozzle after a seal gas is replaced with the flaming gas in a case where a mode is changed from the deposition mode to a non-deposition mode; and replacing the flaming gas flowing to the flaming gas port with a purge gas.

Abstract: A physical quantity measuring apparatus utilizing optical frequency domain reflectometry includes a tunable laser; a first polarization maintaining fiber; a polarization maintaining coupler; a second polarization maintaining fiber; a third polarization maintaining fiber; a sensor consists of a fiber Bragg grating formed in a core of the third polarization maintaining fiber; a fourth polarization maintaining fiber; a photodiode detects Bragg reflected light from the sensor and reference light from the referential reflecting end; a controller that detects modulation of an interference intensity between the Bragg reflected light and the reference light; and an incidence part that inputs the measuring light, wherein the incidence part being provided on the first polarization maintaining fiber or on both the second polarization maintaining fiber and the third polarization maintaining fiber.

Abstract: A method for manufacturing an optical fiber preform and an optical fiber preform apparatus are provided which can reduce hydroxyl groups in an optical fiber preform to a sufficient level without requiring any special equipment or operating conditions. When an optical fiber preform is manufactured by the vapor-phase deposition method, the dehydrating treatment is performed on a porous core preform that is obtained by depositing glass microparticles. In this treatment, a dehydrating agent is supplied to a dehydration apparatus through a feeding pipe and a main feeding pipe made of a material having a water permeance factor of 1.0×10?11 g·cm/cm2·s·cmHg or less, thereby manufacturing an optical fiber preform.

Abstract: A method for manufacturing an optical fiber preform and an optical fiber preform apparatus are provided which can reduce hydroxyl groups in an optical fiber preform to a sufficient level without requiring any special equipment or operating conditions. When an optical fiber preform is manufactured by the vapor-phase deposition method, the dehydrating treatment is performed on a porous core preform that is obtained by deposing glass microparticles. In this treatment, a dehydrating agent is supplied to a dehydration apparatus through a feeding pipe and a main feeding pipe made of a material having a water permeance factor of 1.0×10?11 g·cm/cm2·s·cmHg or less, thereby manufacturing an optical fiber preform.

Abstract: A physical quantity measuring apparatus utilizing optical frequency domain reflectometry of the invention includes a tunable laser; a first polarization-maintaining fiber; a polarization-maintaining coupler; a second polarization-maintaining fiber; a third polarization-maintaining fiber; a sensor consists of fiber Bragg gratings formed at a core of the third polarization-maintaining fiber; a fourth polarization-maintaining fiber; a photodiode detects Bragg reflected light from the sensor and reference light from the referential reflecting end; a controller detects a modulation of an interference intensity between the Bragg reflected light and the reference light, based on an intensity change of multiplexed light of the Bragg reflected light and the reference light; an incidence part inputs the measuring light; and an optical path-length adjuster arranged on the third polarization-maintaining fiber; the incidence part provided on the first polarization-maintaining fiber, or on both the second and third polariz

Abstract: A physical quantity measuring apparatus utilizing optical frequency domain reflectometry of the invention includes a tunable laser; a first polarization-maintaining fiber; a polarization-maintaining coupler; a second polarization-maintaining fiber; a third polarization-maintaining fiber; a sensor consists of fiber Bragg gratings formed at a core of the third polarization-maintaining fiber; a fourth polarization-maintaining fiber; a photodiode detects Bragg reflected light from the sensor and reference light from the referential reflecting end; a controller detects a modulation of an interference intensity between the Bragg reflected light and the reference light, based on an intensity change of multiplexed light of the Bragg reflected light and the reference light; an incidence part inputs the measuring light; and an optical path-length adjuster arranged on the third polarization-maintaining fiber; the incidence part provided on the first polarization-maintaining fiber, or on both the second and third polariz

Abstract: A physical quantity measuring apparatus utilizing optical frequency domain reflectometry includes a tunable laser; a first polarization maintaining fiber; a polarization maintaining coupler; a second polarization maintaining fiber; a third polarization maintaining fiber; a sensor consists of a fiber Bragg grating formed in a core of the third polarization maintaining fiber; a fourth polarization maintaining fiber; a photodiode detects Bragg reflected light from the sensor and reference light from the referential reflecting end; a controller that detects modulation of an interference intensity between the Bragg reflected light and the reference light; and an incidence part that inputs the measuring light, wherein the incidence part being provided on the first polarization maintaining fiber or on both the second polarization maintaining fiber and the third polarization maintaining fiber.

Abstract: A drawing method for a bare optical fiber, comprises the steps of: melting an optical fiber preform using a heating device and drawing the bare optical fiber; and naturally cooling down the bare optical fiber or forcibly cooling down the bare optical fiber by a cooling device after the heating and melting step, wherein a temperature history during the drawing the optical fiber preform to obtain the bare optical fiber in the heating device satisfies a relational expression: T??0.01X+12 where a time period when the heated and molten portion of the optical fiber preform heated and molten by the heating device reaches 1800° C. or higher is T (min) and a OH group concentration in a cladding layer of the optical fiber preform is X (wtppm).

Abstract: A treatment method for an optical fiber including accommodating an optical fiber inside a treatment chamber; introducing a deuterium containing gas into the treatment chamber; and in a deuterium treatment step, exposing the optical fiber to atmosphere of the deuterium containing gas. In the deuterium treatment step, a deuterium concentration D in the treatment chamber during the deuterium treatment is calculated from an initial value A of a deuterium concentration in the deuterium containing gas inside the treatment chamber, a concentration B of oxygen in an ambient atmosphere of the treatment chamber, and a concentration C of oxygen in the deuterium containing gas inside the treatment chamber, and the deuterium concentration in the treatment chamber is controlled based on the deuterium concentration D calculated. Other gases such as hydrogen containing gas or nitrogen containing gas may also be used according to the invention.

Abstract: A porcelain enamel substrate mounts a light emitting device in which a porcelain enamel layer is coated onto a surface of a core metal, and a reflective cup portion that has a flat bottom surface and a sloping portion that surrounds this bottom surface is provided on a light emitting device mounting surface, and an electrode for energizing a light emitting device is provided on the light emitting device mounting surface, and the thickness of the electrode within the reflective cup portion is within a range of 5 ?m to 100 ?m.

Abstract: A method for manufacturing an optical fiber preform and an optical fiber preform apparatus are provided which can reduce hydroxyl groups in an optical fiber preform to a sufficient level without requiring any special equipment or operating conditions. When an optical fiber preform is manufactured by the vapor-phase deposition method, the dehydrating treatment is performed on a porous core preform that is obtained by depositing glass microparticles. In this treatment, a dehydrating agent is supplied to a dehydration apparatus through a feeding pipe and a main feeding pipe made of a material having a water permeance factor of 1.0×10?11 g·cm/cm2·s·cmHg or less, thereby manufacturing an optical fiber preform.