公开(公告)号：US20250044187A1

公开(公告)日：2025-02-06

申请号：US18837117

申请日：2022-02-21

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Atsushi NAKAMURA ,  Yusuke KOSHIKIYA

IPC: G01M11/02 ,  G01M11/00

Abstract: An object of the present invention is to provide an optical fiber testing device and an optical fiber testing method capable of acquiring both unidirectional crosstalk and bidirectional crosstalk of an uncoupled multicore fiber in a short time and with a little man-hour.
The optical fiber testing device 301 according to the present invention includes: the light input unit 10 configured to input test light to an arbitrary core at one end A of the uncoupled multicore fiber 50; the light receiving unit 20 configured to receive output light outputted from each core at the other end B of the uncoupled multicore fiber 50 by the test light and measure light intensity of the output light of each core; and the calculation unit 30 configured to calculate unidirectional transmission crosstalk in a case of performing unidirectional transmission, in which transmission directions of light beams are the same between two cores of the uncoupled multicore fiber 50, from the light intensity of the output light, and calculate bidirectional transmission crosstalk in a case of performing bidirectional transmission, in which transmission directions of light beams are different between two cores of the uncoupled multicore fiber 50, from the unidirectional transmission crosstalk.

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：US20240035808A1

公开(公告)日：2024-02-01

申请号：US18286140

申请日：2021-05-07

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Atsushi NAKAMURA ,  Yusuke KOSHIKIYA ,  Nazuki HONDA

IPC: G01B11/16

CPC classification number: G01B11/16

Abstract: The present disclosure relates to an optical fiber strain measurement method including, in order: a strain amount measurement step S2 of measuring a strain amount εn′ of each core wire of an optical fiber ribbon F; a torsion angle calculation step S3 of calculating a torsion angle γ per unit length of the optical fiber ribbon F on the basis of a difference ε′ in strain amount between an outer core wire and an inner core wire; a torsional strain amount calculation step S4 of calculating a strain amount εn caused by torsion of each core wire of the optical fiber ribbon F on the basis of the torsion angle γ; and a tensile strain amount calculation step S5 of subtracting the strain amount εn from the strain amount εn′, and calculating a strain amount Δεn caused by tension of each core wire of the optical fiber ribbon F.

公开(公告)号：US20210239567A1

公开(公告)日：2021-08-05

申请号：US16973396

申请日：2019-06-04

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Hiroyuki IIDA ,  Tetsuya MANABE ,  Yusuke KOSHIKIYA ,  Hidenobu HIROTA ,  Takui UEMATSU

IPC: G01M11/00 ,  G01M11/02 ,  A61B5/024 ,  H04B10/071

Abstract: An object of the present invention is to provide an optical pulse test apparatus that can test an optical fiber cable at once in a short period of time. The optical pulse test apparatus according to the present invention includes: an optical pulse signal generation unit 11 that emits an optical pulse with a width that is n times as large as a pulse width T corresponding to desired spatial resolution; a light reception unit 12 that receives reflected light and back-scattered light from n FUTs; an optical path control unit 13 that switches paths connected to the n FUTs are connected at an interval T, inject the optical pulse, as a test optical pulse having the pulse width T, sequentially into the paths, then switches the paths at an interval ts that is shorter than the time period T, and emit the reflected light and the back-scattered light from the n FUTs sequentially onto the light reception unit 12 at an interval n×ts; and an arithmetic processing unit 14 that divides the electrical signal output from the light reception unit 12, with an interval equal to the interval ts at which switching the paths is performed, into discrete signals respectively corresponding to the FUTs, and calculates the reflectance distributions of the reflected light and the back-scattered light of the respective FUTs.

公开(公告)号：US20250155277A1

公开(公告)日：2025-05-15

申请号：US18725072

申请日：2022-01-11

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Yoshifumi WAKISAKA ,  Hiroshi TAKAHASHI ,  Daisuke IIDA ,  Yusuke KOSHIKIYA

IPC: G01H9/00

Abstract: In order to achieve the above object, a signal processing method according to the present disclosure includes: a calculation step of calculating a phase change at each of points on a medium from a phase of a reflected signal generated by a pulse signal transmitted to the medium, at each of predetermined times; a phase connection step of performing phase connection processing, at each of the predetermined times, on the phase change at each of the points calculated in the calculation step; and a correction step of detecting an outlier using a phase change at each of the points at the same time at which the phase connection processing is performed in the phase connection step, and correcting the outlier, at each of the predetermined times.

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：US20240280403A1

公开(公告)日：2024-08-22

申请号：US18567606

申请日：2021-06-09

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Yoshifumi WAKISAKA ,  Daisuke IIDA ,  Yusuke KOSHIKIYA ,  Hiroyuki IIDA ,  Nazuki HONDA

IPC: G01H9/00 ,  G01D5/353

CPC classification number: G01H9/004 ,  G01D5/35358

Abstract: The present disclosure relates to a vibration measuring instrument that repeatedly injects a plurality of light pulses with different optical frequencies into an optical fiber, and performs distributed acoustic sensing-phase (DAS-P). In the vibration measuring instrument, light pulses having a waveform with a spectral side lobe smaller than a side lobe of a rectangular wave are used as the plurality of light pulses.

公开(公告)号：US20240146413A1

公开(公告)日：2024-05-02

申请号：US18272188

申请日：2021-01-26

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Tomokazu ODA ,  Daisuke IIDA ,  Atsushi NAKAMURA ,  Yusuke KOSHIKIYA ,  Nazuki HONDA

IPC: H04B10/2537 ,  G01D5/353

CPC classification number: H04B10/2537 ,  G01D5/35364

Abstract: An object of the present invention is to provide a Brillouin gain spectrum distribution measuring method and apparatus capable of measuring a BGS, having a line width narrower than usual, in a distributed manner in the longitudinal direction of an optical fiber under test.
This measuring apparatus prepares pump light in which a pulse is added to continuous light and probe light of continuous light in which a frequency is shifted from the pump light, makes the probe light incident on one end of the FUT and the pump light incident on the other end, and obtains a time waveform of a component amplified by the pump light pulse of a probe light intensity amplified by the pump light. This measuring apparatus changes an optical frequency difference between the pump light and the probe light, and obtains a time waveform for each optical frequency difference. This measuring apparatus obtains a BGS distribution of the FUT from these time waveforms.

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.

公开(公告)号：US20240060817A1

公开(公告)日：2024-02-22

申请号：US18269858

申请日：2021-01-21

Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION

Inventor： Daisuke IIDA ,  Yusuke KOSHIKIYA ,  Nazuki HONDA

IPC: G01H9/00 ,  G01B11/00

CPC classification number: G01H9/004 ,  G01B11/00

Abstract: An object of the present invention is to provide a facility position specification system, a cover, and a facility position specification method capable of specifying a route of an overhead cable without directly giving disturbance to the overhead cable itself.
The facility position specification system according to the present invention includes an optical fiber 25 along an overhead cable 26, a cylindrical cover 40 covering the overhead cable 26 at an arbitrary position on the overhead cable 26 in a longitudinal direction, an optical measuring instrument 20 connected to an end of the optical fiber 25 and configured to acquire temporal change in scattered light from the optical fiber 25 when vibration is applied to the overhead cable 26 from the cover 40 as temporal change in a scattered optical intensity distribution of the optical fiber 25 in a longitudinal direction, and a signal processing unit 21 configured to specify a vibration position on the optical fiber 25 to which the vibration is applied based on the scattered optical intensity distribution, and specify an actual position of the overhead cable 26 to which the vibration is applied by associating the vibration position on the optical fiber 25 with a position of the overhead cable 26 on a map.