公开(公告)号：US20230358599A1

公开(公告)日：2023-11-09

申请号：US18025683

申请日：2020-09-11

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Yoshifumi WAKISAKA ,  Daisuke IIDA ,  Tatsuya OKAMOTO ,  Nazuki HONDA ,  Hiroyuki OSHIDA

IPC: G01H9/00

CPC classification number: G01H9/004

Abstract: An object is to provide a vibration detection apparatus and a vibration detection method which can avoid occurrence of a point where detection sensitivity deteriorates in vibration detection of a scattered light intensity monitor according to optical frequency multiplexing.
The present invention conceives a multi-dimensional space having as many dimensions as the number of frequencies to be used, causes scattered light intensity change at each optical frequency to correspond to each axis, plots a scattered light signal as a vector on the space, performs linear approximation passing through an origin on the space having a plurality of plotted vector points as original data, and performs vibration detection using a direction vector of an approximate straight line obtained as a result of the approximation.

公开(公告)号：US20240192049A1

公开(公告)日：2024-06-13

申请号：US18286460

申请日：2021-04-14

Applicant: Nippon Telegraph and Telephone Corporation

Inventor： Tatsuya OKAMOTO ,  Daisuke IIDA ,  Yusuke KOSHIKIYA ,  Nazuki HONDA

IPC: G01H9/00

CPC classification number: G01H9/004

Abstract: An object of the present invention is to provide a cable test system, an analysis apparatus, a cable test method, and a program capable of recognizing a sag section of an overhead cable without sending a worker to a site.
A cable test system according to the present invention includes an optical fiber vibration distribution measurement apparatus 11 that acquires a vibration distribution waveform of an overhead optical fiber cable 50 to be tested, the vibration distribution waveform being represented in a time domain and a distance domain in a longitudinal direction, and an analysis apparatus 12 that calculates a propagation speed of vibrations propagating through the overhead optical fiber cable 50 from the vibration distribution waveform and detects, as a cable sag section, a section of the overhead optical fiber cable 50 in which the propagation speed is equal to or lower than a threshold value.

公开(公告)号：US20230152170A1

公开(公告)日：2023-05-18

申请号：US17798172

申请日：2020-03-05

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Atsushi NAKAMURA ,  Daisuke IIDA ,  Hiroyuki OSHIDA ,  Tatsuya OKAMOTO ,  Tomokazu ODA ,  Yoshifumi WAKISAKA

IPC: G01L1/24 ,  G01L5/00

CPC classification number: G01L1/242 ,  G01L5/0042

Abstract: An object of the present disclosure is to provide a method and an apparatus for acquiring curvature and torsion using an inexpensive sensor medium. Disclosed is a measurement apparatus including a fiber ribbon including a plurality of coated fibers arranged in parallel, a strain measurement unit that measures strain amounts of the plurality of coated fibers, and an arithmetic processing unit that calculates curvature and torsion of the fiber ribbon using a strain amount of a coated fiber arranged in a middle portion of the plurality of coated fibers and a strain amount of a coated fiber arranged in a marginal portion of the plurality of coated fibers.

公开(公告)号：US20220149934A1

公开(公告)日：2022-05-12

申请号：US17430016

申请日：2020-01-29

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Tatsuya OKAMOTO ,  Daisuke IIDA ,  Hiroyuki OSHIDA

IPC: H04B10/071 ,  H04B10/2507

Abstract: The purpose of the present invention is to provide a device for optical frequency domain reflectometry and a method thereof that can measure a reflectance distribution with less spatial resolution degradation due to a phase noise, without using a wideband receiving system even when a long-distance measurement is performed. The device for optical frequency domain reflectometry according to the present invention is provided with a delay optical fiber for delaying a local light by a prescribed time, and obtains information on a relative delay of a backscattered light from an optical fiber under measurement with respect to the local light and information on the positivity and the negativity of a beat frequency by measuring an in-phase component and a quadrature component of a beat signal obtained by multiplexing the backscattered light from the optical fiber under measurement and the local light delayed by the delay optical fiber, so as to obtain a reflectance distribution in a longitudinal direction of the optical fiber under measurement based on these pieces of information.

公开(公告)号：US20250123415A1

公开(公告)日：2025-04-17

申请号：US18682522

申请日：2021-08-16

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Tatsuya OKAMOTO ,  Daisuke IIDA ,  Yusuke KOSHIKIYA ,  Nazuki HONDA

IPC: G01V1/01 ,  G01H9/00 ,  G01V1/22

Abstract: The present disclosure provides an underground facility position contrast system S, which includes: a scattered light intensity distribution measurement device 1 for measuring, when an earthquake vibration is applied to an optical fiber F laid underground, a change over time in a scattered light intensity distribution in a longitudinal direction of the optical fiber F; and an underground facility position contrast device 2 for measuring a change over time in a distortion response distribution in the longitudinal direction of the optical fiber F based on the change over time in the scattered light intensity distribution in the longitudinal direction of the optical fiber F, estimating an underground facility state of the optical fiber F based on the change over time in the distortion response distribution in the longitudinal direction of the optical fiber F, and associating the underground facility position of the optical fiber F with a longitudinal distance of the optical fiber F.

公开(公告)号：US20240118126A1

公开(公告)日：2024-04-11

申请号：US18275726

申请日：2021-02-17

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Tatsuya OKAMOTO ,  Daisuke IIDA ,  Yusuke KOSHIKIYA ,  Nazuki HONDA

IPC: G01H9/00 ,  G01D5/353

CPC classification number: G01H9/004 ,  G01D5/35358

Abstract: An object of the present disclosure is to provide a method for remotely identifying a utility pole position and estimating a state of an overhead optical fiber cable.
The present disclosure is a method for identifying a utility pole position including identifying a boundary region of a vibration distribution as a utility pole position, from a vibration distribution pattern obtained by measuring strain amounts with respect to distances of an optical fiber by an optical fiber vibration distribution measuring method at each time and sequentially stacking the strain amounts.

公开(公告)号：US20230341245A1

公开(公告)日：2023-10-26

申请号：US18025697

申请日：2020-09-15

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Tatsuya OKAMOTO ,  Daisuke IIDA ,  Hiroyuki OSHIDA

IPC: G01D5/353

CPC classification number: G01D5/35358

Abstract: The present disclosure aims to enable measurement of a long distance exceeding 1 km with a spatial resolution of 100 μm or lower, and diagnosis of health of an optical device installed at a long distance.
An apparatus according to the present disclosure is an optical frequency domain reflectivity measuring apparatus that includes: a local light delay fiber that delays local light; an optical 90-degree hybrid that receives an input of the local light delayed by the local light delay fiber and backscattered light from the measurement target, causes the local light and the backscattered light to interfere with each other, and generates an in-phase component and an orthogonal component of a beat signal generated by the interference; and a balance photodetector that detects the in-phase component and the orthogonal component of the beat signal. In the apparatus, an optical frequency response of the measurement target is measured with respect to a relative distance based on the local light delay fiber.

公开(公告)号：US20230288231A1

公开(公告)日：2023-09-14

申请号：US18020969

申请日：2020-08-26

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Tatsuya OKAMOTO ,  Daisuke IIDA ,  Hiroyuki OSHIDA

IPC: G01D5/353 ,  G01H9/00

CPC classification number: G01D5/35361 ,  G01H9/004

Abstract: An object of the present disclosure is to enable vibration analysis using a spectral shift under appropriate conditions depending on a measurement object.
According to the present disclosure, there is provided a vibration distribution measuring apparatus which measures backscattered light in an optical fiber to be measured a plurality of times at different times, extracts an optical spectrum of a window section determined from a plurality of backscattered light waveforms obtained by the measurement, and measures a vibration distribution in the optical fiber to be measured using optical spectra of the plurality of extracted backscattered light waveforms, in which the optical spectrum of the window section is calculated using the window section in which the vibration amplitude in the window section in the optical fiber to be measured is larger than a threshold value defined in the window section.

公开(公告)号：US20240295433A1

公开(公告)日：2024-09-05

申请号：US18551642

申请日：2021-03-23

Applicant: Nippon Telegraph and Telephone Corporation

Inventor： Yoshifumi WAKISAKA ,  Tatsuya OKAMOTO ,  Daisuke IIDA ,  Yusuke KOSHIKIYA ,  Masashi KIKUCHI ,  Nazuki HONDA

IPC: G01H9/00 ,  G01D5/353 ,  G01M11/00

CPC classification number: G01H9/004 ,  G01M11/3109 ,  G01D5/35358

Abstract: A signal processing method executed by a signal processing device, includes performing a phase connection process on a position in a space and a phase value at each of a plurality of times, performing outlier correction of a phase value for each position in the space in a predetermined direction of the space at a predetermined time among the plurality of times based on a result of the phase connection process, and correcting a phase value at a time other than the predetermined time for each of correction target positions among positions in the space.

公开(公告)号：US20240118127A1

公开(公告)日：2024-04-11

申请号：US18275848

申请日：2021-02-26

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Daisuke IIDA ,  Yoshitaka ENOMOTO ,  Chihiro KITO ,  Tatsuya OKAMOTO ,  Yusuke KOSHIKIYA ,  Yoshifumi WAKISAKA ,  Nazuki HONDA

IPC: G01H9/00

CPC classification number: G01H9/004

Abstract: The present disclosure is an optical line test system that detects a distribution of loss points of an optical line in a longitudinal direction, using a coherent light measurement device, applies vibration to facility disposed on a path of the optical line, detects a vibration point of the optical line in a longitudinal direction upon applying the vibration, using the coherent light measurement device, and identifies the loss point based on correspondence between the detected loss point and vibration point.