公开(公告)号：US20130136409A1

公开(公告)日：2013-05-30

申请号：US13754963

申请日：2013-01-31

Applicant: FURUKAWA ELECTRIC CO., LTD. ,  NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Naomi Kumano ,  Iwao Shimotakahara ,  Ryuichi Sugizaki ,  Takeshi Yagi ,  Tomoya Shimizu ,  Takashi Matsui ,  Yukihiro Goto ,  Toshio Kurashima ,  Kazuhide Nakajima

IPC: G02B6/032

CPC classification number: G02B6/032 ,  G02B6/02333 ,  G02B6/02366 ,  G02B6/03627

Abstract: A hole-assisted optical fiber includes a core portion and a cladding portion that includes an inner cladding layer, an outer cladding layer, and holes formed around the core portion. A diameter of the core portion is 3 μm to 9.8 μm, a relative refractive index difference of the core portion relative to the outer cladding layer is 0.11% to 0.45%, an outside diameter of the inner cladding layer is 53 μm or less, a relative refractive index difference of the inner cladding layer relative to the outer cladding layer is a negative value, −0.30% or more, a diameter of each hole is 2.4 μm to 4.0 μm, a hole occupancy rate is 17% to 48%, a bending loss at a wavelength of 1625 nm when bent at a radius of 5 mm is 1 dB/turn or less, and a cut-off wavelength is 1550 nm or less.

Abstract translation: 空穴辅助光纤包括芯部和包括内包层，外包层和形成在芯部周围的孔的包层部分。 芯部的直径为3μm〜9.8μm，芯部相对于外包层的相对折射率差为0.11〜0.45％，内包层的外径为53μm以下，a 内包层相对于外包层的相对折射率差为-0.30％以上的负值，每个孔的直径为2.4μm〜4.0μm，孔占有率为17〜48％，a 以5mm的半径弯曲时，波长1625nm处的弯曲损耗为1dB /匝以下，截止波长为1550nm以下。

公开(公告)号：US12203847B2

公开(公告)日：2025-01-21

申请号：US17915924

申请日：2021-06-03

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION ,  THE UNIVERSITY OF TOKYO

Inventor： Nobutomo Hanzawa ,  Kazuhide Nakajima ,  Takashi Matsui ,  Hideaki Murayama ,  Ryota Wada ,  Makito Kobayashi

IPC: G01N21/47 ,  G01N21/63 ,  G01N21/954

Abstract: A shape measurement system and method for a three-dimensional shape of a linear object over a long distance with high resolution. The shape measurement system comprises: a multicore optical fiber having a center core positioned in the center of the cross section thereof and three or more outer peripheral cores positioned at equal intervals concentrically with respect to and outside of the center core; a measurement device for measuring the backward Brillouin scattered light distribution in the propagation direction of each core of the multicore optical fiber; and an analysis device for calculating position coordinates, in three-dimensional space, of a linear structure having an unknown three-dimensional shape from the backward Brillouin scattered light distributions of a multicore optical fiber positioned along the linear structure having an unknown three-dimensional shape and a multicore optical fiber positioned along a linear structure having a known three-dimensional shape.

公开(公告)号：US20240427078A1

公开(公告)日：2024-12-26

申请号：US18822957

申请日：2024-09-03

Applicant: Nippon Telegraph and Telephone Corporation

Inventor： Takashi Matsui ,  Kazuhide Nakajima

IPC: G02B6/02 ,  G02B27/00

Abstract: There are provided a multi-core optical fiber including four step-index type cores with a standard cladding diameter and having excellent mass productivity, quality, and yield while meeting desired specifications, and a design method thereof. A multi-core optical fiber according to the present disclosure includes: four cores arranged in a square lattice shape along a longitudinal direction, each of the four cores having a step-index type refractive index distribution with a radius a; and a cladding region having a lower refractive index than that of each core and a diameter of 125±1 μm and provided on an outer peripheral portion of each core, where an absolute value of a relative refractive index difference between each core and the cladding region is Δ. The four cores are arranged so that a relationship between a minimum distance (OCT) from the center of each core to an outer periphery of the cladding region, a minimum value Λ of spacing between the cores, and the MFD at a wavelength of 1310 nm satisfies Formula C1, and the radius a of each core and the relative refractive index difference Δ between the core and the cladding region are set. [ Formula ⁢ C ⁢ 1 ] OCT ≥ 3.73 MFD + 3.43 ⁢ Λ ≤ - 5.28 ⁢ MFD + 83.54 ( C1 )

公开(公告)号：US12117645B2

公开(公告)日：2024-10-15

申请号：US18232524

申请日：2023-08-10

Applicant: Nippon Telegraph and Telephone Corporation

Inventor： Takashi Matsui ,  Kazuhide Nakajima

IPC: G02B6/02 ,  G02B27/00

CPC classification number: G02B6/02042 ,  G02B6/02004 ,  G02B27/0012

Abstract: A multi-core optical fiber includes four cores arranged in a shape along a longitudinal direction, each of the four cores having a step-index type refractive index distribution with a radius, and a cladding region having a lower refractive index than that of each core and a diameter of 125±1 μm and provided on an outer portion of each core. An absolute value of a relative refractive index difference between each core and the cladding region is Δ. The four cores are arranged so that a relationship between a minimum distance from the center of each core to an outer periphery of the cladding region, a minimum value A of spacing between the cores, and the MFD at a set wavelength satisfies a Formula C1, and the radius of each core and the relative refractive index difference Δ between the core and the cladding region are set.

公开(公告)号：US20240250757A1

公开(公告)日：2024-07-25

申请号：US18290383

申请日：2021-05-19

Applicant: Nippon Telegraph and Telephone Corporation

Inventor： Chisato Fukai ,  Tomohiro TANIGUCHI ,  Kazuhide Nakajima ,  Ayako IWAKI ,  Takashi Matsui ,  Nobutomo HANZAWA ,  Yuto SAGAE ,  Kazutaka HARA ,  Atsuko KAWAKITA

IPC: H04B10/80 ,  G02B6/02 ,  G02B6/04 ,  G02B6/10

CPC classification number: H04B10/801 ,  G02B6/02042 ,  G02B6/04 ,  G02B6/102

Abstract: An object of the present invention is to provide an ultraviolet optical transmission system in which cutting of an optical fiber or a complicated procedure is not necessary when an optical fiber is exchanged.
The present invention provides a system in which light with an ultraviolet band is transmitted along an optical transmission path formed of a quartz-based optical fiber, and in which an optical transmission unit is switched by a rotation mechanism in which an optical transmission path of one of an optical coupling unit rotates about an axis, the optical coupling unit including an optical transmission path including a plurality of optical transmission units on the same circumference from a center on an end surface of the optical coupling unit; an optical transmission path in which the optical transmission units are arranged on the same circumference as a circumference on which the plurality of optical transmission units are arranged; two ferrules each containing the two optical transmission paths; and a cylindrical sleeve in which the two ferrules are inserted in a hollow.

公开(公告)号：US12019267B2

公开(公告)日：2024-06-25

申请号：US17627866

申请日：2020-07-21

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Taiji Sakamoto ,  Kazuhide Nakajima ,  Takashi Matsui ,  Kyozo Tsujikawa ,  Kunimasa Saitoh ,  Takeshi Fujisawa

IPC: G02B6/02 ,  G02B27/00

CPC classification number: G02B6/02042 ,  G02B27/0012

Abstract: An object of the present invention is to provide a multi-core optical fiber that can prevent an increase in bending loss even when a distance between a peripheral core and a cladding boundary is decreased, and can improve a bending loss characteristic in a state where an influence on a cutoff wavelength and a mode field diameter is small, and a design method thereof.
The multi-core optical fiber according to the present invention is an optical fiber in which two or more core regions are arranged in a cladding region having a refractive index lower than a refractive index of the core at a minimum core interval, a ring-shaped low refractive index region surrounding the core and having a refractive index lower than the refractive index of the cladding region is provided, a bending loss after the provision of the ring-shaped low refractive index region is reduced as compared with a characteristic in a case where the ring-shaped low refractive index region is not provided, and at the same time, a change in mode field diameter after the provision of the ring-shaped low refractive index region is not changed as compared with a characteristic in a case where the ring-shaped low refractive index region is not provided.

公开(公告)号：US10545333B2

公开(公告)日：2020-01-28

申请号：US15772263

申请日：2016-11-17

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Takashi Matsui ,  Kazuhide Nakajima ,  Kyozo Tsujikawa ,  Fumihiko Yamamoto

IPC: G02B6/032 ,  G02B6/02 ,  G02B27/00

Abstract: A photonic crystal fiber according to the present invention has a plurality of holes arranged in the optical fiber along a longitudinal direction, in which the holes are arranged such that, in a cross section, a hole ratio which is an area of the holes per unit area is larger in a central side than in an outer side in a portion corresponding to a cladding and that a wide core area can be obtained while the number of modes that can be propagated is limited to several. Moreover, in a high-power optical transmission system according to the present invention, the amount of axis misalignment between the central axis of a laser oscillator and the central axis of the photonic crystal fiber is less than or equal to a certain amount.

公开(公告)号：US12085749B2

公开(公告)日：2024-09-10

申请号：US18009784

申请日：2020-06-24

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Nobutomo Hanzawa ,  Takashi Matsui ,  Yuto Sagae ,  Kazuhide Nakajima

IPC: H04B10/00 ,  G02B6/02 ,  H04J14/00

CPC classification number: G02B6/02042 ,  G02B6/02342

Abstract: The purpose of the present invention is to provide an optical fiber evaluation equipment and an optical fiber evaluation method that evaluate the center of a cladding of an MCF and a deviation of the center of each core of the MCF from a design value with ease and high accuracy.
The optical fiber evaluation equipment according to the present invention approximates the outside diameter of a cladding by a circle, based on a cross-sectional image of an MCF, and determines the center of the circle as the center of the cladding. In addition, the optical fiber evaluation equipment according to the present invention obtains the center coordinates of cores with an origin at the center of the circle, rotates the cross-sectional image so as to minimize a difference between the center coordinates and design coordinates of each core, and derives the minimum value thereof as the amount of deviation of the center of each core.

公开(公告)号：US11906783B2

公开(公告)日：2024-02-20

申请号：US17764239

申请日：2019-10-08

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Yoko Yamashita ,  Masaki Wada ,  Takashi Matsui ,  Kazuhide Nakajima

IPC: G02B6/293 ,  G02B6/38

CPC classification number: G02B6/29313 ,  G02B6/3861

Abstract: An object of the present invention is to provide a core position recognition method, a connection method, and a connection apparatus that can simplify connection operations, and reduce rotational displacement and positional displacement. The connection apparatus according to the present invention includes a function capable of acquiring the rotation amount of an MCF during the bonding/fixing step. Specifically, the connection apparatus of the present invention uses an MCF with lines drawn on a side surface thereof, thereby recognizing the rotation amount of the MCF from the side surface, and calculating the absolute positions of the cores. The connection apparatus according to the present invention can recognize the absolute position s of the cores from a side image of an MCF in a state in which the MCF has been rotated. By forming a waveguide on a glass substrate serving as a connection destination so as to match the absolute positions of the cores, the rotational and positional displacements of the MCF can be eliminated, thus making it possible to reduce the connection loss.

公开(公告)号：US20240027678A1

公开(公告)日：2024-01-25

申请号：US18232524

申请日：2023-08-10

Applicant: Nippon Telegraph and Telephone Corporation

Inventor： Takashi Matsui ,  Kazuhide Nakajima

IPC: G02B6/02 ,  G02B27/00

CPC classification number: G02B6/02042 ,  G02B6/02004 ,  G02B27/0012

Abstract: There are provided a multi-core optical fiber including four step-index type cores with a standard cladding diameter and having excellent mass productivity, quality, and yield while meeting desired specifications, and a design method thereof.
A multi-core optical fiber according to the present disclosure includes: four cores arranged in a square lattice shape along a longitudinal direction, each of the four cores having a step-index type refractive index distribution with a radius a; and a cladding region having a lower refractive index than that of each core and a diameter of 125±1 μm and provided on an outer peripheral portion of each core, where an absolute value of a relative refractive index difference between each core and the cladding region is Δ. The four cores are arranged so that a relationship between a minimum distance (OCT) from the center of each core to an outer periphery of the cladding region, a minimum value Λ of spacing between the cores, and the MFD at a wavelength of 1310 nm satisfies Formula C1, and the radius a of each core and the relative refractive index difference Δ between the core and the cladding region are set.


[Formula C1]



OCT≥3.73MFD+3.43



Λ≤−5.28MFD+83.54  (C1)