公开(公告)号：US20190339513A1

公开(公告)日：2019-11-07

申请号：US16507570

申请日：2019-07-10

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Takashi MATSUI ,  Kazuhide NAKAJIMA ,  Kyozo TSUJIKAWA ,  Fumihiko YAMAMOTO

IPC: G02B27/00 ,  G02B6/02 ,  G02B6/032 ,  G02B6/42

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：US20190004246A1

公开(公告)日：2019-01-03

申请号：US15752809

申请日：2016-03-03

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Takashi MATSUI ,  Kyozo TSUJIKAWA ,  Fumihiko YAMAMOTO ,  Nobutomo HANZAWA

IPC: G02B6/02 ,  G02B6/42

CPC classification number: G02B6/02347 ,  B23K26/702 ,  G02B6/02 ,  G02B6/02314 ,  G02B6/02333 ,  G02B6/0288 ,  G02B6/42 ,  G02B6/4206

Abstract: An optical fiber that is a photonic crystal fiber in which a plurality of holes is arranged along a longitudinal direction of the optical fiber, having a predetermined bending radius R determined according to a transmission distance L of the optical fiber and optical power output from the optical fiber, and having an inter-hole distance Λ and a ratio d/Λ between a hole diameter d and the inter-hole distance Λ such that light of a predetermined number of modes is transmitted and a bending loss of the light of a fundamental mode with the predetermined bending radius R is equal to or smaller than a predetermined value.

公开(公告)号：US20180321439A1

公开(公告)日：2018-11-08

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: G02B6/02 ,  G02B6/032

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：US20180341104A1

公开(公告)日：2018-11-29

申请号：US15771040

申请日：2016-11-17

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Takashi MATSUI ,  Kazuhide NAKAJIMA ,  Kyozo TSUJIKAWA ,  Fumihiko YAMAMOTO

IPC: G02B27/00 ,  G02B6/02

Abstract: An optical fiber design method according to the present invention is a design method of a photonic crystal fiber having a plurality of holes arranged in the optical fiber along a longitudinal direction, in which a required effective cross-sectional area is calculated from a light wavelength, a transmission distance, and output power 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 a fiber structure (hole diameter and hole interval) corresponding to the effective cross-sectional area is calculated.

公开(公告)号：US20180172902A1

公开(公告)日：2018-06-21

申请号：US15563988

申请日：2016-03-22

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Takashi MATSUI ,  Kyozo TSUJIKAWA ,  Fumihiko YAMAMOTO ,  Nobutomo HANZAWA

IPC: G02B6/02

CPC classification number: G02B6/02328 ,  G02B6/02009 ,  G02B6/02309 ,  G02B6/02314 ,  G02B6/02347

Abstract: An object of the present invention is to provide a structure of an optical fiber capable of satisfying desired requirements of an output power, a propagation distance, and a beam quality. In the design of the PCF of the present invention, the PCF has air holes having diameters d and intervals Λ in an overlapping region where a region of Aeff of a desired value or more and a cutoff region in a desired higher-order mode overlap each other on a graph where the horizontal axis represents d/Λ and the vertical axis represents Λ, so that it is possible to sufficiently cut off the mode which is the desired higher-order mode or more, and thus, it is possible to select a region where the Aeff is large.

公开(公告)号：US20170160466A1

公开(公告)日：2017-06-08

申请号：US15440228

申请日：2017-02-23

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

Inventor： Katsunori IMAMURA ,  Tomohiro GONDA ,  Ryuichi SUGIZAKI ,  Taiji SAKAMOTO ,  Takayoshi MORI ,  Masaki WADA ,  Takashi YAMAMOTO ,  Fumihiko YAMAMOTO

IPC: G02B6/02 ,  C03B37/16 ,  C03B37/012 ,  G02B6/028

CPC classification number: G02B6/02042 ,  C03B37/01205 ,  C03B37/01222 ,  C03B37/027 ,  C03B37/16 ,  C03B2203/10 ,  C03B2203/18 ,  C03B2203/22 ,  C03B2203/23 ,  C03B2203/26 ,  C03B2203/34 ,  C03B2205/30 ,  G02B6/0288 ,  G02B6/0365

Abstract: A multicore fiber includes a plurality of unit multicore fibers each including: a plurality of core portions; and a clad portion which is formed in an outer circumference of the core portions and has a refractive index lower than a maximum refractive index of the core portions. The plurality of the core portions have substantially same refractive index profile and different group delays at same wavelength in same propagation mode. The core portions of the multicore fiber are configured so that the core portions of the plurality of the unit multicore fibers are connected in cascade, a maximum value of differential group delays between the core portions of the multicore fiber is smaller than a reduced value of a maximum value of differential group delays between the core portions of each unit multicore fiber as a value in terms of a length of the multicore fiber.