公开(公告)号：US20210234326A1

公开(公告)日：2021-07-29

申请号：US17266181

申请日：2019-08-06

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Yoko YAMASHITA ,  Masaki WADA ,  Takashi MATSUI ,  Kazuhide NAKAJIMA

IPC: H01S3/067 ,  G02B27/00

Abstract: Provided is a differential modal attenuation compensation fiber that has a simple structure and can reduce MDL while eliminating the need for precise alignment work, an optical amplifier, and a transmission line design method. The differential modal attenuation compensation fiber according to the present invention, imparts excess loss to a desired propagation mode by forming a cavity portion or a ring-shaped high refractive index portion in a core of an optical fiber. By forming the cavity portion or the ring-shaped high refractive index portion in a part of the profile of the core, electric field distribution of a particular mode propagating through the fiber can be controlled, and different losses can be imparted to different propagation modes at an interface between the cavity portion or the ring-shaped high refractive index portion and a region not including the cavity portion or the ring-shaped high refractive index portion.

公开(公告)号：US20250093575A1

公开(公告)日：2025-03-20

申请号：US18294124

申请日：2021-08-04

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Takashi MATSUI ,  Kazuhide NAKAJIMA ,  Nobutomo HANZAWA ,  Yuto SAGAE

IPC: G02B6/02

Abstract: An object of the present disclosure is to provide an optical fiber having a simple structure, as well as attaining removal of loss components generated in an electric field part oozing out to a core-clad interface or a clad region and reduction in scattering loss generated from an interface with the clad region.
The present disclosure relates to an optical fiber including a core for propagating light, a cladding disposed around the core, an air layer between the core and the cladding, and two or more bridges for supporting the core in the air layer.

公开(公告)号：US20250076568A1

公开(公告)日：2025-03-06

申请号：US18293918

申请日：2021-08-02

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Nobutomo HANZAWA ,  Takayoshi MORI ,  Takashi MATSUI ,  Yoko YAMASHITA ,  Kazuhide NAKAJIMA

IPC: G02B6/02

Abstract: The present disclosure is a photonic crystal fiber in which a plurality of holes are formed in a cladding, having a uniform light refractive index, capable of propagating three modes of a fundamental mode, a first higher-order mode, and a second higher-order mode, wherein the plurality of holes are disposed in a triangular lattice pattern so as to surround a center of the photonic crystal fiber with no hole disposed at the center of the photonic crystal fiber, and the photonic crystal fiber has a ratio d/A of a diameter d of each of the holes to a pitch A between the holes such that a confinement loss of a third higher-order mode at a minimum wavelength within a used wavelength range is 1.0 dB/m or more and a confinement loss at a maximum wavelength is 0.001 dB/km or less.

公开(公告)号：US20240375093A1

公开(公告)日：2024-11-14

申请号：US18690903

申请日：2021-09-24

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Asuka MIYAKE ,  Hitoshi SESHIMO ,  Ryuji YAMAMOTO ,  Tomohiro TANIGUCHI ,  Ayako IWAKI ,  Satoshi NARIKAWA ,  Takahito KIRIHARA ,  Kazuhide NAKAJIMA ,  Takashi MATSUI ,  Yuto SAGAE ,  Chisato FUKAI ,  Nobutomo HANZAWA

IPC: B01J35/39 ,  A61L2/10 ,  B01J35/54

Abstract: An object of the present invention is to provide a photocatalytic sheet configured to perform disinfection independent of the state of external light.
A photocatalytic sheet 50 according to the present invention includes a sheet 10 having a photocatalytic layer 17 on one surface, and an optical fiber 20 embedded in the sheet 10 and configured to supply ultraviolet light UV from inside of the sheet 10 to the photocatalytic layer 17. In the photocatalytic sheet, ultraviolet light is supplied from the optical fiber disposed in the sheet to the photocatalytic layer coated on the surface of the sheet (ultraviolet light is supplied from the back of the photocatalytic layer). This configuration allows for disinfection independent of the state of external light.

公开(公告)号：US20240277886A1

公开(公告)日：2024-08-22

申请号：US18693133

申请日：2021-09-30

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Asuka MIYAKE ,  Hitoshi SESHIMO ,  Ryuji YAMAMOTO ,  Tomohiro TANIGUCHI ,  Ayako IWAKI ,  Satoshi NARIKAWA ,  Takahito KIRIHARA ,  Kazuhide NAKAJIMA ,  Takashi MATSUI ,  Yuto SAGAE ,  Chisato FUKAI ,  Nobutomo HANZAWA

IPC: A61L9/20 ,  F24F8/22

CPC classification number: A61L9/20 ,  F24F8/22 ,  A61L2209/12 ,  A61L2209/16

Abstract: An object of the present invention is to provide an air conditioner unit that allows for greater flexibility in designing the shape of the unit and is capable of reducing the cost of lamp replacement.
An air conditioner unit according to the present invention includes an optical fiber group 17 formed by bundling a plurality of optical fibers 16 emitting a part of propagating light from side faces thereof; an air duct 10 that incorporates the optical fiber group 17 in a space 13 through which air passes; and a light source 30 that supplies ultraviolet light to each of the optical fibers 16. Since the intensity of the light is inversely proportional to the square of the distance from the light source, if the same sterilization effect is to be obtained, the irradiation intensity of the ultraviolet light can be reduced when the irradiation distance is shorter. In other words, in this air conditioner unit, since the plurality of optical fibers 16 are arranged in the air duct 10, the air (air flow) in the air duct 10 can be sterilized by the ultraviolet light of the LED having a small output from the light source 30.

公开(公告)号：US20240072507A1

公开(公告)日：2024-02-29

申请号：US18269611

申请日：2021-01-21

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Shinichi AOZASA ,  Taiji SAKAMOTO ,  Kazuhide NAKAJIMA ,  Takashi MATSUI

IPC: H01S3/10 ,  F21V8/00

CPC classification number: H01S3/10023 ,  G02B6/0003

Abstract: The purpose of the present invention is to provide an optical fiber amplifier capable of seamlessly and collectively amplifying optical signals in a plurality of bands.
In order to achieve the aforementioned purpose, the optical fiber amplifier according to the present invention is the optical fiber amplifier that amplifies multiple wavelength bands, and in cross-section, one signal light primary propagation region, and a doped region where rare-earth ions have been added, wherein the doped region includes the rare-earth-doped optical fiber existing other than the propagation region. The optical fiber amplifier uses the fact that the main propagation regions of the signal light are made the same in the fiber cross-section of the rare-earth-doped optical fiber and the propagation regions of the signal light are partially different in the signal wavelength, and adds rare-earth ions to the partially different propagation regions to make amplification factors different for each signal wavelength and flatten the gain of each amplification wavelength band.

公开(公告)号：US20230324604A1

公开(公告)日：2023-10-12

申请号：US18024559

申请日：2020-09-09

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Ryota IMADA ,  Yoko YAMASHITA ,  Takashi MATSUI ,  Taiji SAKAMOTO ,  Nobutomo HANZAWA ,  Noriyuki ARAKI ,  Shinichi AOZASA ,  Yuto SAGAE ,  Kazuhide NAKAJIMA

IPC: G02B6/02

CPC classification number: G02B6/02095

Abstract: Provided are an LPFG and an optical transmission system in which a mode conversion amount does not depend on a polarization state and an electric field distribution. The LPFG according to the present invention includes cavity rows (25-1 and 25-2) of cavities 15 periodically arranged in a core region 11 of the few-mode fiber 10 at a position away from a central axis z of the core region 11 in parallel with the central axis z. Each of the cavity rows (25-1 and 25-2) is located at a different position in a longitudinal direction of the few-mode fiber 10 (where the position in a z direction is different), and the cavity rows (25-1 and 25-2) are located at positions shifted by 90° on a cross section of the core region 11 with the center of the cross section of the core region 11 (the intersection of an x-axis and a y-axis) as an origin.

公开(公告)号：US20230310674A1

公开(公告)日：2023-10-05

申请号：US18015685

申请日：2020-11-02

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Tomohiro TANIGUCHI ,  Ayako IWAKI ,  Kazuhide NAKAJIMA ,  Nobutomo HANZAWA ,  Takashi MATSUI ,  Yuto SAGAE ,  Chisato FUKAI ,  Kazutaka HARA ,  Atsuko KAWAKITA

IPC: A61L2/10 ,  A61L2/24 ,  G02F1/37

CPC classification number: A61L2/10 ,  A61L2/24 ,  G02F1/37 ,  A61L2202/11

Abstract: An object of the present invention is to provide a light irradiation system capable of securing economic efficiency, flexibility, reliability, and safety, and further capable of reducing a transmission loss between a center side and a remote side.
The present light irradiation system can secure economic efficiency by sharing a single light source installed on the center side with a plurality of irradiation places. The present light irradiation system can irradiate a place to be sterilized with ultraviolet light output by moving the optical fiber tip end on the remote side in a pinpoint manner, and can also secure flexibility. In addition, the present light irradiation system can secure reliability and safety by performing output control of the light source on the center side. Furthermore, in the present light irradiation system, light in a low-loss wavelength region is transmitted from the center side through the optical fiber, wavelength conversion is performed on the remote side, and thus the transmission loss between the center side and the remote side can be reduced.

公开(公告)号：US20230147800A1

公开(公告)日：2023-05-11

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

CPC classification number: G01N21/47 ,  G01N21/636 ,  G01N21/954 ,  G01N2021/4709 ,  G01N2021/638 ,  G01N2021/9546

Abstract: An object is to provide a shape measurement system and a shape measurement method that allow deriving a three-dimensional shape of a linear object to be measured over a long distance and with high resolution. A shape measurement system according to the present invention includes: a multi-core optical fiber (10) including a center core (11) arranged in a center of a cross section of the multi-core optical fiber (10) and three or more outer peripheral cores (12) arranged at equal intervals on an outside of the center core (11) and in a concentric manner; a measuring device (20) that measures a backward Brillouin scattering light distribution in a propagation direction of each core of the multi-core optical fiber (10); and an analysis device (30) that computes positional coordinates in a three-dimensional space of a linear structural object having an unknown three-dimensional shape from the backward Brillouin scattering light distribution of the multi-core optical fiber (10) arranged along the linear structural object having the unknown three-dimensional shape and the multi-core optical fiber (10) arranged along a linear structural object having an already-known three-dimensional shape.

公开(公告)号：US20220276430A1

公开(公告)日：2022-09-01

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

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.