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公开(公告)号：US20210278272A1
公开(公告)日：2021-09-09
申请号：US17256532
申请日：2019-06-19
Applicant: Nippon Telegraph and Telephone Corporation
Inventor： Kunihiro Toge , Daisuke Iida , Shingo Ono , Yoshifumi Wakisaka , Tetsuya Manabe
Abstract: A distributed optical fiber vibration measurement device includes a phase constant difference computation unit causing the first backscattered light generated at the points of a plurality of optical fibers under test that are integrated to interfere with another light to obtain two AC components and determining a phase constant difference from the two AC components, a phase distribution data creation unit comparing amplitudes between the two AC components obtained by causing the first backscattered light generated at the points of the optical fibers under test to interfere with the other light and selecting, for each of the points, phase data regarding one of the two AC components having a larger amplitude to create phase distribution data with the phase data, and a vibration measurement unit identifying an optical path length difference between any two points of the optical fiber under test to measure vibration of the optical fiber under test.
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公开(公告)号：US20210255005A1
公开(公告)日：2021-08-19
申请号：US17275327
申请日：2019-09-12
Applicant: Nippon Telegraph and Telephone Corporation
Inventor： Tatsuya Okamoto , Daisuke Iida , Hiroyuki Oshida , Tetsuya Manabe
Abstract: A manhole position identification method of the present invention includes: measuring, from an end of an optical fiber, a temporal variation in scattering light from the optical fiber when an impact blow is applied to a cover of a manhole located on a path of the optical fiber, so as to obtain temporal variations in a scattering light intensity distribution in a longitudinal direction of the optical fiber; determining an occurrence of vibration due to the impact blow based on the temporal variations at positions in the scattering light intensity distribution, so as to identify an impact blow position on the optical fiber; and associating the impact blow position on the optical fiber with a map position of the manhole whose cover has received the impact blow, so as to identify a position of the manhole expressed in terms of optical fiber length from the end.
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13.发明授权公开(公告)号：US12031858B2
公开(公告)日：2024-07-09
申请号：US17429861
申请日：2020-01-29
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Tatsuya Okamoto , Daisuke Iida , Hiroyuki Oshida
IPC: G01H9/00 , G01M11/00 , H04B10/071
CPC classification number: G01H9/004 , G01M11/30 , H04B10/071
Abstract: It is an object of the present invention to provide an aerial optical fiber cable inspection method, an aerial optical fiber cable inspection device, and a program which can identify a cable sagging section from vibration sensing results. In the aerial optical fiber cable inspection method according to the present invention, a vibration distribution waveform along the longitudinal direction of an aerial optical fiber cable measured using an optical fiber vibration sensing device is received as an input, a standard deviation of the amplitude of vibration at each position in the vibration distribution waveform is calculated, and a section with a standard deviation larger than that of other sections is identified as a cable sagging section.
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公开(公告)号：US11644347B2
公开(公告)日：2023-05-09
申请号：US17275327
申请日：2019-09-12
Applicant: Nippon Telegraph and Telephone Corporation
Inventor： Tatsuya Okamoto , Daisuke Iida , Hiroyuki Oshida , Tetsuya Manabe
CPC classification number: G01D5/35306 , E02D29/14 , G01D5/35358 , G01H9/004
Abstract: A manhole position identification method of the present invention includes: measuring, from an end of an optical fiber, a temporal variation in scattering light from the optical fiber when an impact blow is applied to a cover of a manhole located on a path of the optical fiber, so as to obtain temporal variations in a scattering light intensity distribution in a longitudinal direction of the optical fiber; determining an occurrence of vibration due to the impact blow based on the temporal variations at positions in the scattering light intensity distribution, so as to identify an impact blow position on the optical fiber; and associating the impact blow position on the optical fiber with a map position of the manhole whose cover has received the impact blow, so as to identify a position of the manhole expressed in terms of optical fiber length from the end.
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公开(公告)号：US11463163B2
公开(公告)日：2022-10-04
申请号：US17430016
申请日：2020-01-29
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Tatsuya Okamoto , Daisuke Iida , Hiroyuki Oshida
IPC: H04B10/07 , H04B10/071 , H04B10/2507 , G01M11/00 , H04B10/61 , H04B10/63 , H04B10/64
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.
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Patent Agency Ranking
公开(公告)号：US11976962B2
公开(公告)日：2024-05-07
申请号：US15734211
申请日：2019-05-29
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Yoshifumi Wakisaka , Daisuke Iida , Kunihiro Toge , Tetsuya Manabe
CPC classification number: G01H9/004 , G01B17/04 , G01D5/35358
Abstract: An object is to provide an optical fiber path search method, an optical fiber path search system, a signal processor, and a program that can be operated free of the effects of walls, supporting members, and the like so that only a signal generated by an acoustic wave propagating through the air can be extracted. An optical fiber path search system according to the present invention utilizes DAS and includes: a vibration source 304 configured to provide an acoustic wave to a predetermined region; a light reflection measurement device 305 configured to be connected to one end of an optical fiber 302 and configured to measure vibration of a change in an optical path length from the other end of the optical fiber 302 to a point in the optical fiber 302 due to the acoustic wave provided by the vibration source 304; and a signal processor 313 configured to extract a signal component in a high frequency region higher than a preset cutoff frequency from a signal of the vibration of the change in the optical path length measured by the light reflection measurement device 305 and calculate a distance between the vibration source 304 and the point in the optical fiber 302 using the signal component.
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公开(公告)号：US11867555B2
公开(公告)日：2024-01-09
申请号：US17440514
申请日：2020-03-19
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Yoshifumi Wakisaka , Daisuke Iida , Kunihiro Toge , Hiroyuki Oshida
CPC classification number: G01H9/004 , G01D5/35383
Abstract: It is intended to provide a phase measurement method and a signal processing device that are capable of reducing influence of noise of a measuring device without increasing the peak intensity of an incident light pulse when measuring the phase of scattered light in DAS-P.
A phase measurement method according to the present invention causes wavelength-multiplexed pulse light to be incident on a measurement target optical fiber, produces a scattered light vector obtained by plotting scattered light from the measurement target optical fiber for each wavelength onto a two-dimensional plane having the in-phase component thereof on the horizontal axis and the orthogonal component thereof on the vertical axis, rotates the produced scattered light vector for each wavelength at each place in the measurement target optical fiber to align the directions of the vectors, generates a new vector by calculating the arithmetic average of the vectors having the aligned directions, and calculates the phase by using the values of the in-phase and orthogonal components of the generated new vector.-
公开(公告)号：US11860028B2
公开(公告)日：2024-01-02
申请号：US17427792
申请日：2020-01-22
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Yoshifumi Wakisaka , Daisuke Iida , Keiji Okamoto , Hiroyuki Oshida
IPC: G01H9/00
CPC classification number: G01H9/004
Abstract: A vibration detection method is presented to accurately detect vibration physically applied to an optical fiber, using a simple determination reference. In a vibration detection method, scattered light of a given target segment of a measurement target fiber is indicated by vectors of an in-phase component and a quadrature component, and a triangular shape constituted by a near-end-side vector of the target segment and a far-end-side vector is used as a physical amount to be tracked. That is, it is determined whether or not there is vibration based on a change in shape of the triangular shape with respect to a reference state. This is a detection method in which DAS-I and DAS-P are combined, a simple determination reference such as shape change of a triangular shape is employed, and overlooking of vibration detection can be reduced.
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公开(公告)号：US11788909B2
公开(公告)日：2023-10-17
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
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.
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公开(公告)号：US11750283B2
公开(公告)日：2023-09-05
申请号：US17427651
申请日：2020-01-17
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Daisuke Iida , Nazuki Honda , Tatsuya Okamoto , Yoshifumi Wakisaka , Hiroyuki Oshida
IPC: H04B10/27 , H04B10/071 , H04B10/2507
CPC classification number: H04B10/071 , H04B10/2507 , H04B10/27
Abstract: An object is to provide an optical fiber route search method, an optical fiber route search device, and a program that can efficiently confirm a path of an optical fiber that is installed over a long distance or across a large range. The optical fiber route search method according to the present invention carries out optical measurement that performs distributed measurement of the state of an optical fiber while applying a disturbance to the optical fiber in a portion in which wires of the optical fiber are parallel to each other, branch out, or intersect with each other (a proximity portion), and determines that the position in which the number of singularities (peaks or intensity fluctuations) fluctuates (becomes plural) is the position of the proximity portion from a distribution diagram obtained through the optical measurement.
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