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：US20240361551A1

公开(公告)日：2024-10-31

申请号：US18682993

申请日：2021-08-19

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Yusuke YAMADA ,  Kazuhide NAKAJIMA

IPC: G02B6/44

CPC classification number: G02B6/4413

Abstract: An object of the present invention is to ensure low crosstalk for all multi-core optical fibers in an optical fiber cable having a plurality of identical multi-core optical fibers of non-coupling type in different spiral shapes.
An optical fiber cable according to the present disclosure is an optical fiber cable formed by twisting a plurality of units each of which is formed by bundling a plurality of identical multi-core optical fibers of non-coupling type, which includes: that all the units have the same diameter; that the units are arranged in a plurality of layers from a center in a cross section; that the units are arranged in a spiral shape for each of the layers in a longitudinal direction; that all the units included in one of the layers have the same twist pitch of the spiral shape; and that the twist pitch is different for each layer, and is set based on a curvature Rpk of the multi-core optical fiber where crosstalk is the largest.

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：US20220360358A1

公开(公告)日：2022-11-10

申请号：US17760541

申请日：2019-09-17

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Taiji SAKAMOTO ,  Masaki WADA ,  Takashi YAMAMOTO ,  Kazuhide NAKAJIMA

IPC: H04J14/04 ,  H04B10/2581 ,  H04B7/0413 ,  H04B10/079

Abstract: An object of the present invention is to provide an optical transmission system capable of controlling a transmission capacity and a signal processing load of a MIMO equalizer, without depending on the number of propagation modes of the optical fiber. The present optical transmission system includes an optical fiber 11 with the number of spatial modes being L (an integer of 2 or greater), an optical multiplexer 13 connected to one end of the optical fiber 11 and configured to input M (a natural number of L or less) signal beams of light to the optical fiber 11 and cause the M input signal beams of light to be propagated for each of the spatial modes of the optical fiber 11, an optical demultiplexer 14 connected to another end of the optical fiber 11 and configured to demultiplex a propagated beam of light propagated through the optical fiber 11 for each of the spatial modes of the optical fiber 11, N (N=L) receivers 15 configured to each receive a demultiplexed beam of light obtained by demultiplexing the propagated beam of light, a signal generation apparatus 17 configured to generate P (an integer of from M to L) combined signals from the N received signals, and a P×M MIMO equalizer 16 configured to receive the P combined signals to output M demodulated signals.

公开(公告)号：US20220344888A1

公开(公告)日：2022-10-27

申请号：US17762403

申请日：2019-09-26

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Shinichi AOZASA ,  Taiji SAKAMOTO ,  Kazuhide NAKAJIMA ,  Masaki WADA

IPC: H01S3/067

Abstract: An objective of the present invention is to provide an amplification fiber having a cladding excitation configuration that improves amplification efficiency and an optical amplifier. An amplification fiber (10) according to the present invention is a multi-core amplification fiber having, from one end (E1) to the other end (EE), a plurality of cores (11b) in a cladding (11a), and a total distance from the one end (E1) to the other end (EE) in which rare earth ions are doped differs depending on the types of cores (11b). The cores (11b) are preferably disposed such that the cores of the same type are not adjacent to each other. By arranging the types of the cores in this manner, requirements for inter-core crosstalk can be mitigated since the bands of signal light in the adjacent cores are different. As a result, a density of cladding excitation light can be increased by shortening the inter-core distance, and thus the amplification efficiency can be improved.

公开(公告)号：US20220334307A1

公开(公告)日：2022-10-20

申请号：US17641061

申请日：2019-09-18

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Saki NOZOE ,  Nobutomo HANZAWA ,  Yuto SAGAE ,  Kazuhide NAKAJIMA ,  Kyozo TSUJIKAWA

IPC: G02B6/02 ,  G02B6/032

Abstract: An object of the present invention is to provide an HAF having a structure in which the number of air holes is decreased to be smaller than that of a PCF and Rayleigh scattering loss may be more reduced than that in the existing HAF. The HAF according to the present invention includes a core portion having a uniform optical refractive index; a cladding portion having a uniform optical refractive index and surrounding the core portion; and a plurality of air holes arranged in two layers at positions configuring hexagonal closest packing excluding the core portion within the cladding portion along a longitudinal direction of the hole-assisted fiber, wherein a center-to-center spacing of the air holes is a sum of a radius Rin of an inscribed circle inscribed in the air holes in an inner layer and a radius d/2 of the air hole, and a radius “a” of the core portion and a relative refractive index difference Δ between the core portion and the cladding portion are present within a range where Rn, which is a ratio of a Rayleigh scattering coefficient Rsmf of a single mode optical fiber and an effective Rayleigh scattering coefficient Reff of the hole-assisted fiber, is equal to or less than 0.92.