Abstract: An optical fiber according to an embodiment has a structure capable of reducing an increase in transmission loss. The optical fiber includes a glass part extending in a direction of a central axis, and the glass part is comprised of silica-based glass, includes a core and a cladding, and has residual stress approximately uniform throughout a cross section of the glass part orthogonal to the central axis, the core having the central axis and being doped with chlorine with a mass fraction of 1% or more, the cladding surrounding the core and having a refractive index lower than a maximum refractive index of the core.

Abstract: A glass rod manufacturing device includes: a holding portion configured to hold one end of a starting rod; a heating portion configured to heat a bent portion; and a centering jig configured to apply a force in a first direction intersecting an axis to a part of the starting rod that whirls between the bent portion and another end of the starting rod due to rotation of the starting rod about an axis. The centering jig includes: an abutment portion configured to abut against the part; an elastic displacement portion configured to elastically displace the abutment portion in the first direction according to a run-out deviation of whirl of the part; and a slide portion configured to slide the abutment portion in a second direction intersecting the axis and the first direction according to the run-out deviation of whirl of the part.

Abstract: A multi-core optical fiber includes: a pair of cores; and a cladding that covers both of the pair of cores. A diameter of the cladding is 124 ?m or more and 126 ?m or less. A distance between centers of the pair of cores is 46.5 ?m or less. Cross talk between counter-propagating cores at a wavelength of 1550 nm is ?30 dB/100 km or less.

Abstract: A multicore optical fiber of an embodiment has a structure for simultaneously realizing low transmission loss, low fusion splicing loss, and low inter-core crosstalk. The multicore optical fiber includes a plurality of cores comprised of silica glass, a common cladding comprised of silica glass and surrounding the plurality of cores, and a resin coating surrounding the common cladding. The common cladding has a refractive index lower than a refractive index of the plurality of cores. Each of the plurality of cores contains chlorine at 10000 ppm or more in at least part thereof.

Abstract: A method for manufacturing an optical fiber preform made of silica-based glass, the method including: forming a core portion; and forming a cladding portion surrounding the core portion, the cladding portion having a refractive index lower than a refractive index of the core portion, wherein the forming the core portion includes: adding an alkali element group consisting of an alkali metal element and an alkaline earth metal element to an inner surface of a glass pipe made of silica-based glass; and integrating the glass pipe and a glass rod disposed inside the glass pipe to form an integrated rod after the adding.

Abstract: An MCF includes a plurality of cores each extending in a direction along a central axis and a cladding covering each of the plurality of cores. The cladding includes a low refractive index barrier. The low refractive index barrier includes an alkali metal element. A relative refractive index of the low refractive index barrier is lower than an average value of a relative refractive indices of the cladding overall. The core interval is set such that a total sum of the power coupling coefficients between a specific core among the plurality of cores and each of all remaining cores is 2.3×10?4/km or less.

Abstract: One embodiment of the present disclosure relates to an optical fiber having lower transmission loss. The optical fiber is an optical fiber comprised of silica-based glass and includes a core including a central axis and a cladding. The cladding surrounds the core and has a refractive index lower than a refractive index of the core. The core contains phosphorus, chlorine, and fluorine. The core further includes an alkali metal element or an alkaline earth metal element. In a cross section of the optical fiber orthogonal to the central axis, a ratio Rp/Ra of a radius Rp of a phosphorus-containing region with respect to a radius Ra of the core is 0.3 or more.

Abstract: The MCF of the present disclosure suppresses occurrence of structural abnormality such as air bubbles in the vicinity of a boundary between a marker and a cladding. The MCF includes a glass optical fiber including a plurality of cores, a marker, and a cladding, and a resin coating. On a cross section of the MCF, centers of the plurality of cores and a center of the marker constitute a plane figure having a rotational symmetry of order 1 with respect to a center of the cross section. Moreover, on the cross section, the marker is disposed so as to be located on a circumference of a circle having a center coinciding with the center of the cross section and having the circumference passing through the respective centers of the plurality of cores.

Abstract: An optical fiber is formed from silica-based glass. The optical fiber includes a core including a central axis and a cladding surrounding the core. A refractive index of the core is greater than a refractive index of the cladding. The core contains chlorine, and one or more kinds of elements selected from an element group consisting of alkali metal elements and alkaline earth metal elements. A relative refractive index difference of the core based on a refractive index of pure silica is 0.00% or greater and 0.15% or less. An average concentration of fluorine in the cladding is 1.2% or less in a mass fraction.

Abstract: An optical fiber has a structure uniform in a longitudinal direction. This optical fiber includes a core and a cladding that surrounds the core in a cross-section perpendicular to the longitudinal direction. A refractive index of the cladding is lower than a refractive index of the core. The cladding has, in the cross-section, an inner cladding layer including an inner circumferential surface of the cladding, and an outer cladding layer including an outer circumferential surface of the cladding. The inner cladding layer contains fluorine. The inner and outer cladding layers have refractive indexes different from each other. The outer cladding layer includes a local maximum portion where a residual stress, which is a tensile stress, becomes local maximum. A radial distance between the local maximum portion and an inner circumferential surface of the outer cladding layer is 10 ?m or less.

Abstract: A method for manufacturing an optical fiber preform includes: adding an alkali metal element or an alkaline earth metal element to an inner surface of a glass pipe made of silica-based glass; reducing a diameter of the glass pipe after the adding; etching an inner surface of a continuous section of the glass pipe in a longitudinal direction after the reducing; and collapsing the glass pipe after the etching. At least one of the adding, the reducing, the etching, and the collapsing includes performing a local etching on an inner surface of a section of the glass pipe that is shorter than the continuous section.

Abstract: Provided is a method for evaluating a sample, the method including using a mixture containing a sample including at least one member selected from the group consisting of cell support-derived components, a cell suspension containing cells, an evaluation sample obtained from a cell suspension, a sample containing a liquid and microcarriers for use in cell culture, and a sample containing a liquid obtained following treatment of microcarriers, together with at least one substance selected from the group consisting of an aromatic compound having at least one functional group selected from the group consisting of a hydroxyl group, an amino group, a nitro group and a carbonyl group, and a fluorescent dye.

Abstract: An optical fiber according to an embodiment has a structure capable of reducing an increase in transmission loss. The optical fiber includes a glass part extending in a direction of a central axis, and the glass part is comprised of silica-based glass, includes a core and a cladding, and has residual stress approximately uniform throughout a cross section of the glass part orthogonal to the central axis, the core having the central axis and being doped with chlorine with a mass fraction of 1% or more, the cladding surrounding the core and having a refractive index lower than a maximum refractive index of the core.

Abstract: One embodiment relates to an organic electronic material containing a charge transport polymer, wherein the charge transport polymer is a polymer which, when 25 ?L portions of methanol are added dropwise and stirred into 1,000 ?L of a solution containing the charge transport polymer and toluene in a ratio of 20 mg of the charge transport polymer per 2,290 ?L of toluene, the amount of methanol added by the time cloudiness develops in the solution is greater than 350 ?L.

Abstract: Objects of the disclosure are to provide a preanalysis treatment method for a sample, which can reduce mixing of a reagent into the sample, and to provide a sample pretreatment system capable of performing the preanalysis treatment method. An aspect of the present embodiment is a preanalysis treatment method for a sample, which includes a step A of mixing the sample and a reagent A containing a support and a reducing agent immobilized on the support, a step B of mixing the sample and a reagent B containing a support and an enzyme immobilized on the support, a step X-A of, after the step A, separating the reagent A and a supernatant from each other, and a step X-B of, after the step B, separating the reagent B and a supernatant from each other.

Abstract: An optical fiber has a structure uniform in a longitudinal direction. This optical fiber includes a core and a cladding that surrounds the core in a cross-section perpendicular to the longitudinal direction. A refractive index of the cladding is lower than a refractive index of the core. The cladding has, in the cross-section, an inner cladding layer including an inner circumferential surface of the cladding, and an outer cladding layer including an outer circumferential surface of the cladding. The inner cladding layer contains fluorine. The inner and outer cladding layers have refractive indexes different from each other. The outer cladding layer includes a local maximum portion where a residual stress, which is a tensile stress, becomes local maximum. A radial distance between the local maximum portion and an inner circumferential surface of the outer cladding layer is 10 ?m or less.

Abstract: An optical amplifier is provided in which adjacent ones of a plurality of cores each containing a rare-earth element and included in an amplifying multi-core optical fiber (MCF) serve as coupled cores at an amplifying wavelength, a connecting MCF is connected to the amplifying MCF, a pump light source is connected to the connecting MCF, and the pump light source pumps the rare-earth element in the amplifying MCF through the connecting MCF.

Abstract: The present embodiment relates to an optical amplifier and the like having a structure for enabling efficient use of pumping light while avoiding complication of a device structure. In such an optical amplifier, since pumping light from a pumping light source is supplied to each core of an amplification MCF, a coupling MCF in which adjacent cores form a coupled core is arranged between the amplification MCF and the pumping light source. The pumping light source is optically connected to a specific core of the coupling MCF, and pumping light is coupled from the specific core to remaining cores except the specific core in the coupling MCF before pumping light is supplied to each core of the amplification MCF. This enables coupling of pumping light between optically connected cores between the amplification MCF and the coupling MCF.

Abstract: An optical fiber having an effective area that can be easily increased and bending loss characteristics that can be easily improved is provided. The optical fiber includes a glass fiber including a core and a cladding; a first resin coating layer that is in contact with the glass fiber and surrounds the glass fiber; and a second resin coating layer that surrounds the first resin coating layer and has a Young's modulus greater than a Young's modulus of the first resin coating layer. An effective area is greater than or equal to 110 ?m2 and less than or equal to 180 ?m2 at a wavelength of 1550 nm. A cable cut-off wavelength is less than or equal to 1530 nm. A uniformity of thickness of the first resin coating layer is greater than or equal to 60% and less than or equal to 80%.

Abstract: A method for manufacturing an optical fiber includes: heating an optical fiber preform to draw glass fiber; measuring an outer diameter of the glass fiber to obtain a function of time; transforming the function of time into a function of frequency; identifying a first peak caused by a first drawing condition and a second peak caused by a second drawing condition in the function of frequency; and adjusting the second drawing condition so as to satisfy fn<fm?wm/2 or fn>fm+wm/2, where fm is a frequency of the first peak, wm is a full width at half maximum of the first peak, and fn is a frequency of the second peak.