Sumitomo Electric Industries, Limited

Takuji Nagashima

Takashi Sasaki

Tetsuya Nakanishi

Tetsuya Hayashi

Toshiki Taru

Atsushi Inoue

Eisuke Sasaoka

Osamu Shimakawa

Tetsu Morishima

Akira Kawai

Naoki Matsushita

Kazuo Kaneko

Kimiaki Sato

A manufacturing method includes forming one or more first holes in a cladding rod, inserting a first glass rod into each of the one or more first holes, heating the cladding rod together with the inserted first glass rod to integrate the first glass rod and the cladding rod and to form an intermediate preform, forming one or more second holes in the intermediate preform, inserting a second glass rod into each of the one or more second holes, and heating the intermediate preform together with the inserted second glass rod to integrate the second glass rod and the intermediate preform.

Manufacturing method for preform of multi-core fiber and manufacturing method for multi-core fiber

An MCF according to the disclosure has a structure preventing deterioration in quality of optical transmission signals. The MCF comprises cores, a common cladding, and a coating. Any of the cores has a coating leakage loss of 0.01 dB/km or more at a wavelength within a wavelength range of from 850 nm to 1700 nm. The coating includes a leaked light propagation suppressive coating layer having a first optical property or a second optical property to light with a wavelength within a wavelength range of from 850 nm to 1700 nm or from 1260 nm to 1625 nm. The first optical property is defined by, as an attenuation index of the light, an absorbance per 1 &#x3bc;m thickness being 0.1 dB or more. The second optical property is defined by a product of absorbance per 1 &#x3bc;m thickness and a thickness being 0.1 dB or more.

Multi-core optical fiber

Provided is an optical fiber manufacturing method that uses a low-cost large optical fiber preform having high precision. The optical fiber manufacturing method includes at least a positioning step of positioning core rods in a hollow carbon pipe that contains carbon as a main component, a soot preform preparation step of filling a gap between the carbon pipe and the core rods with silica powder that contains SiOas a main component, thereby producing a soot preform, a consolidating step of introducing the soot preform into a furnace and consolidating the silica powder, thereby producing a transparent intermediate preform from the soot preform, an extraction step of extracting the transparent intermediate preform from the carbon pipe, and a drawing step of drawing the transparent intermediate preform, thereby manufacturing an optical fiber.

Optical fiber manufacturing method

A method for manufacturing a multicore optical fiber includes a step of forming ring-shaped closed-end holes to axially extend from a first end toward a second end of a glass rod; a step of heating bottom parts of the ring-shaped closed-end holes and softening center rods surrounded by the ring-shaped closed-end holes; a step of pulling out the center rods toward a side of the first end, forming columnar closed-end holes from the ring-shaped closed-end holes, and treating the glass rod as a cladding material; a connecting step of connecting a supporting pipe to the first end; an inserting step of inserting core rods into the columnar closed-end holes after the connecting step; and a drawing step of drawing the cladding material and the core rods while heating a portion near the second end and integrating the cladding material and the core rods after the inserting step.

Method for manufacturing multicore optical fiber

An optical connector manufacturing method includes inserting a protrusion of a fixing jig into a positioning hole in an end face of a cladding of an optical fiber and restraining rotation of the optical fiber, the positioning hole extending in an optical axis direction, the optical fiber being inserted in a through hole in a connector ferrule and protruding from an end face of the connector ferrule; and securing the optical fiber to the connector ferrule, with the protrusion of the fixing jig inserted in the positioning hole.

Optical connector manufacturing method

A method and an apparatus for measuring a profile of a beam output from a randomly-coupled multi-core fiber are provided. An apparatus includes a light source, a measurement unit, and an analysis unit. Light output from the light source is input in one or more of a plurality of spatial modes of the fiber at an input end of the fiber. The measurement unit measures a sum of intensity profiles of individual light components output from respective ones of the plurality of spatial modes by averaging a component of interference between the plurality of spatial modes in a beam profile of combined light output from the plurality of spatial modes at an output end of the fiber. The analysis unit calculates an MFD and/or Aof the fiber based on the sum of the intensity profiles of the individual light components obtained by the measurement unit.

Optical-fiber output beam profile measurement method and optical-fiber output beam profile measurement apparatus

There is provided a method for producing a multicore optical fiber while depressurizing holes in a common cladding tube. A production method for a multicore optical fiber includes a preform forming step of forming a common cladding tube having a plurality of holes extending between a first end and a second end, an end-face working step of digging the common cladding tube from the second end to a predetermined depth to forming a third end, a connection step of connecting a glass tube to the second end, an insertion step of inserting core rods into the holes to the third end, a sealing step of sealing the first end, and a drawing step of spinning the multicore optical fiber while depressurizing the holes through the glass tube and combining the common cladding tube and the core rods from the first end.

Production method for multicore optical fiber

There is provided a method for producing a multicore optical fiber while reducing the mass of a glass block to be connected to a common cladding tube. A production method for a multicore optical fiber includes in order, a preform forming step of forming a common cladding tube having a plurality of holes extending between a first end and a second end, an insertion step of inserting core rods in the holes in a state in which end portions of the core rods are recessed from the first end, a heat shrinkage step of reducing a diameter of the first end by heating, a sealing step of sealing the holes by connecting a glass block to the first end, and a drawing step of depressurizing insides of the holes from the second end and performing spinning from the first end while combining the common cladding tube and the core rods.

Provided is a method for producing a multicore optical fiber (MCF) in which variations in positions of cores relative to the outer shape of the MCF are small. The method includes: an integrating step of heating a common cladding tube and a core rods, thereby integrating the tube with the core rods to form a core-cladding composite body including a plurality of cores and a common cladding and having a noncircular cross-sectional shape; an outline detecting step of detecting the outline of the composite body; an optical fiber preform forming step of machining the outer circumferential surface of the composite body using results obtained in the outline detecting step to form the preform having a flat surface; and a drawing step of drawing one end of the preform under heating to obtain the MCF. Also provided is a MCF for which a rotation alignment operation is easily performed.

Method for producing multicore optical fiber and multicore optical fiber

An embodiment of the invention enables each core in an end face to be readily identified by observation of either one end face, regardless of the presence or absence of a twist of a pertinent MCF and difference of ends. In a cross section of the MCF, a core group constellation has symmetry but each core in a core group is identifiable by breaking of all types of symmetry in a common cladding, defined by a combination of the core group constellation with the common cladding, or, by making the fiber ends distinguishable.

Optical fiber

A multi-core optical fiber ribbon easily optically connected to another optical component is provided. A multi-core optical fiber ribbonincludes a plurality of multi-core optical fibersarranged parallel to one another and a common resin, with which the plurality of multi-core optical fibersare collectively coated. A core arrangement direction in which plurality of cores in each of the plurality of multi-core optical fibersare arranged is parallel to or perpendicular to the fiber arrangement direction in which the plurality of multi-core optical fibersare arranged at least at both ends of the multi-core optical fiber ribbon

Multi-core optical fiber tape

There is provided a multi-core fiber that can reduce both skew and crosstalk between cores. The multi-core fiber includes a plurality of cores extending along a fiber axis, and optical claddings surrounding the plurality of cores. The skew between optical signals propagating through the plurality of cores is 1 ps/m or less, and the propagation constant difference between two adjacent cores of the plurality of cores is more than 0.

Multi-core fiber

A multi-core optical fiberA in which a plurality of cores can easily be identified even in the case where they are symmetrically arranged in its section has seven coresto, a visual recognition marker, and a shared claddingenclosing the seven corestoand the visual recognition marker. The coresto, the visual recognition marker, and the claddingare respectively made of silica glass as their main element. The corestoand the visual recognition markerextend along the fiber-axis direction. The respective refractive index of the corestois higher than the refractive index of the cladding. The refractive index of the visual recognition markerdiffers from that of the cladding. In the cross-section perpendicular to the fiber-axis, the corestoare arranged such that they have 6-fold rotational symmetry and line symmetry. The visual recognition markeris arranged at a position which breaks such symmetry.

A multi-core optical fiberA in which a plurality of cores can easily be identified even in the case where they are symmetrically arranged in its section has seven coresto, a visual recognition marker, and a shared claddingenclosing the seven corestoand the visual recognition marker. The corestoand the visual recognition markerextend along the fiber-axis direction. The respective refractive index of the corestois higher than the refractive index of the cladding. The refractive index of the visual recognition markerdiffers from that of the cladding. In the cross-section perpendicular to the fiber-axis, the corestoare arranged such that they have 6-fold rotational symmetry and line symmetry. The visual recognition markeris arranged at a position which breaks such symmetry.

Multi-core optical fibre

The present invention provides an optical branching device and an optical communication system which are easy to connect with optical fibers. In the optical branching device, when light emitted from an optical fiber in a front stage is incident on an entrance port of a multicore optical fiber, the light propagates through a first core and then is distributed from the first core to four second cores by core-to-core crosstalk between the first and second cores. The light beams distributed to the four second cores propagate through the respective cores and are emitted to four optical waveguides optically coupled core-to-core thereto within a fan-out part at exit ports.

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Yokohama, Japan

Takuji Nagashima