The Furukawa Electric Co., Ltd.

Nissan Chemical Industries Limited

Mitsubishi Electric Corporation

Hewlett-Packard Company

Otis Elevator Company

Mitsubishi Eiectric Corporation

Koichi Maeda

Ryuichi Sugizaki

Masanori Takahashi

Shigehiro Takasaka

Hiroshi Sata

Masayoshi Tsukamoto

Kenichiro Toriumi

Hajime Fujimoto

Ataru Nakamura

Kengo Watanabe

Kohei Kawasaki

Yukihiro Tsuchida

Fumio Suzuki

Tsunetoshi Saito

Hisao Ikeda

Haruo Ito

Hideki Takamatsu

Yasuhiro Takahashi

Mitsunobu Matsumura

Yoshitane Watanabe

Hiroshi Matsuura

Shinichi Arai

Katsuaki Miyaji

Keizo Tanikawa

Ryozo Sakoda

Takeshi Mita

Yoshihiro Arashitani

Katsunori Imamura

Masateru Tadakuma

Yu Mimura

Keiichi Aiso

Ryo Miyabe

Hiroshi Murakami

Gozyo Sakata

Hitomi Suzuki

Takashi Tanaka

Shigeto Matsumoto

Kazuhiko Motomura

Yoshitane Watanbe

Yoshito Aoishi

Hirosi Murakami

Yoshio Tsukahara

A multicore fiber includes: a plurality of core portions made of glass; and a cladding portion made of glass and configured to surround outer periphery of the plurality of core portions. The cladding portion has tensile stress of 20 MPa or lower in a region on outer periphery side than a core portion that is closest to outer periphery of the cladding portion in the plurality of core portions.

Multicore fiber, manufacturing method for multicore fiber, multicore fiber preform, and manufacturing method for multicore fiber preform

A multicore fiber includes: a plurality of first glass regions each including: a core portion; and a first cladding portion having a lower refractive index than a maximum refractive index of the core portion; and a cladding region formed on outer peripheries of the plurality of first glass regions, wherein compressive stress is applied to the plurality of first glass regions.

Multicore fiber

An optical fiber bundle structure includes: a plurality of optical fiber core wires; and a capillary, wherein each of the optical fiber core wires includes a glass fiber portion including a core and a clad, and a resin coated portion, the glass fiber portions are inserted in the capillary, and d2/d1 is equal to or larger than 0.57 and smaller than 1, where d1 is a diameter of the core of each of the glass fiber portions in a rear end portion of the capillary and d2 is a diameter of the core of each of the glass fiber portions in a distal end portion of the capillary.

Optical fiber bundle structure, optical fiber connection structure, and optical fiber bundle structure manufacturing method

A multi-core optical amplifying fiber includes: core portions doped with a rare-earth element; an inner cladding portion; and an outer cladding portion. A mode field diameter of each core portion at a wavelength at which the rare-earth element performs optical amplification is 5 μm to 11 μm, a relative refractive-index difference of the maximum refractive index of each core portion with respect to the inner cladding portion is 0.35% to 2%, a core-to-core distance is set such that total inter-core crosstalk is −40 dB/100 m or lower in an optical amplification wavelength band subjected to the optical amplification, a cladding thickness is smaller than a value obtained by adding the mode field diameter to a minimum value of the core-to-core distance, and a ratio of a total sectional area of the core portions to a sectional area of the inner cladding portion is 1.9% or more.

Multi-core optical amplifying fiber, multi-core optical fiber amplifier, and optical communication system

An optical fiber bundle structure includes: plural optical fiber core wires; a crossing preventing member; and a grasping member. Further, the crossing preventing member has slits and the widths of the slits positioned at the respective sides are each equal to or larger than a difference between: a length of one side of a polygon circumscribing the plural optical fiber core wires at a hindmost end portion of the slits at the trailing end; and a length of one side of a polygon circumscribing the plural optical fiber core wires at the leading end.

Optical fiber bundle structure, optical connector, optical fiber connection structure, and method of manufacturing optical fiber bundle structure

A multicore fiber includes: n pieces of first core regions in a circular shape with a radius rthat are arranged about points Pto P, and that has a first core portion and a first cladding portion; a second core region in a circular shape with a radius Rthat is arranged about the point a, and that has a second core portion and a second cladding portion; and a cladding region that is formed on an outer circumferences of the first core region and the second core region. Further, abutting surfaces that are flat surfaces abutting on each other are formed in portions on the outer circumferences of the first core region and the second core region.

Manufacturing method of multicore fiber preform, multicore fiber preform, and multicore fiber

An aim is to provide an optical coupler that contributes increasing pump-efficiency in an optical amplifier, and the optical amplifier. The optical amplifier includes: a main optical fiber that includes a core transmitting signal light, an inner cladding portion formed around an outer periphery of the core and having a refractive index lower than a refractive index of the core, and an outer cladding portion formed around an outer periphery of the inner cladding portion and having a refractive index lower than the refractive index of the inner cladding portion, a part of the outer cladding portion of which in a longitudinal direction being removed; and at least one pump-light input-output optical fiber that is fusion-spliced to the inner cladding portion of the main optical fiber at the portion where the outer cladding portion is removed, an average refractive index of which in a contact region where the pump-light input-output optical fiber is in contact with the inner cladding portion being larger than the refractive index of the inner cladding portion. Pump-light propagating in the pump-light input-output optical fiber is coupled to the inner cladding portion from the contact region and propagates in the inner cladding portion, or the pump-light propagating in the inner cladding portion is coupled to the pump-light input-output optical fiber from the contact region and propagates in the pump-light input-output optical fiber.

Optical coupler and optical amplifier

Refrigerating machine

Rack for refrigerating machine

A multi-core optical amplifying fiber device includes a plurality of multi-core optical amplifying fibers including a plurality of core portions doped with amplification medium and a cladding portion formed at outer peripheries of the plurality of core portions; and a connection portion connecting the core portions of the plurality of multi-core optical amplifying fibers to one another. The connection portion connects the core portions to restrain deviation, between every connected core portions, of amplification gain for a total length of the core portions connected one another.

Multi-core optical amplifying fiber device and multi-core optical fiber amplifier

A bundle structure is obtained by arranging optical fibers having equal diameters in a close-packed arrangement around the outer circumference of a center optical fiber. The optical fibers are signal light optical fibers that transmit signal lights. The optical fiber is a pump light optical fiber that transmits pump light. The number of optical fibers is equal to the number of cores in the multi-core fiber. The bundle structure and the multi-core fiber are connected to one another by adhering or fusing. The cores and the cores are optically connected, and the core and the cladding are optically connected. When connecting, the mode field diameter of the cores and the cores are substantially equivalent. In addition, the outer diameter (diameter of circumscribed circle including optical fibers) of the bundle structure is set so as not to be greater than the outer diameter of the multi-core fiber.

Optical-fiber-bundle structure, rare-earth-doped multi-core fiber, connection structure therefor, method for exciting rare-earth-doped multi-core fibers, and multi-core-optical-fiber amplifier

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Tokyo, Japan

Koichi Maeda