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公开(公告)号：US20210396626A1
公开(公告)日：2021-12-23
申请号：US17281186
申请日：2019-09-18
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Keiji OKAMOTO , Atsushi NAKAMURA , Hiroyuki OSHIDA
IPC: G01M11/02 , H01S3/30 , H04B10/071 , H04B10/2537
Abstract: The present invention is to provide a backscattered light amplification device, an optical pulse test apparatus, a backscattered light amplification method, and an optical pulse test method for amplifying a desired propagation mode of Rayleigh backscattered light with a desired gain by stimulated Brillouin scattering in a fiber under test having the plurality of propagation modes. The backscattered light amplification device according to the present invention is configured to control individually power, incident timing, and pulse width of a pump pulse for each propagation mode when the pump pulse is incident in a plurality of propagation modes after the probe pulse is input to the fiber under test in any propagation mode.
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公开(公告)号：US20210356358A1
公开(公告)日：2021-11-18
申请号：US17286605
申请日：2019-06-06
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Atsushi NAKAMURA , Keiji OKAMOTO , Hiroyuki OSHIDA
IPC: G01M11/00
Abstract: An optical pulse test apparatus according to the present disclosure includes a light generation unit configured to generate an optical pulse for generating backscattered light beams in an optical fiber under test and generate first light having an optical frequency for amplifying backscattered light in an LP11 mode out of the backscattered light beams in two LP modes through stimulated Brillouin scattering, and second light having an optical frequency for attenuating backscattered light in an LP01 mode out of the backscattered light beams in the two LP modes through stimulated Brillouin scattering, a mode demultiplexing unit configured to input the optical pulse, the first light, and the second light generated by the light generation unit into the optical fiber under test in the LP01 mode and separate, out of the backscattered light beams generated by the optical pulse, the backscattered light in the LP11 mode, a local oscillation light generation unit configured to generate local oscillation light by which the backscattered light separated by the mode demultiplexing unit is heterodyne-detected, a light reception unit configured to multiplex the backscattered light in the LP11 mode separated by the mode demultiplexing unit and the local oscillation light generated by the local oscillation light generation unit and photoelectrically convert the multiplexed light into an electrical signal, and an arithmetic processing unit configured to calculate a time-intensity distribution of the electrical signal obtained by the light reception unit photoelectrically converting the backscattered light in the LP11 mode.
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33.发明公开公开(公告)号：US20230288287A1
公开(公告)日：2023-09-14
申请号：US18020958
申请日：2020-08-21
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Atsushi NAKAMURA , Daisuke IIDA , Tomokazu ODA , Hiroyuki OSHIDA
IPC: G01M11/00
CPC classification number: G01M11/31
Abstract: An object of the present disclosure is to provide a power coupling coefficient measurement method and a power coupling coefficient measurement device capable of inexpensively and easily measuring a power coupling coefficient. The power coupling coefficient measurement method according to the present disclosure is a power coupling coefficient measurement method for measuring a power coupling coefficient of a multi-core fiber in order to achieve the aforementioned object, and includes: inputting a test light pulse from one end of the multi-core fiber to any one of cores; receiving backscattered light of the core to which the test light pulse is input or any one of the other cores; measuring an intensity distribution of the backscattered light with respect to a distance from the one end of the multi-core fiber; and calculating the power coupling coefficient from the intensity distribution of the backscattered light.
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公开(公告)号：US20230221153A1
公开(公告)日：2023-07-13
申请号：US17928264
申请日：2020-06-03
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Kazutaka NOTO , Nazuki HONDA , Hiroyuki OSHIDA
CPC classification number: G01D21/02 , G01M11/02 , G01M11/3109
Abstract: The present disclosure is directed to enabling detection of microbending even in a case where a microbending loss varies.
The present disclosure relates to a device that measures a transmission loss in a measured optical fiber to be targeted, and detects microbending in the measured optical fiber based on periodicity of the transmission loss.-
公开(公告)号：US20230175884A1
公开(公告)日：2023-06-08
申请号：US17766494
申请日：2019-10-17
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Yoshifumi WAKISAKA , Daisuke IIDA , Hiroyuki OSHIDA
IPC: G01H9/00
CPC classification number: G01H9/004
Abstract: An object of the present invention is to propose a design method of a minimum value N of the number of multiplexed frequencies that is necessary for measuring an object vibrational frequency according to DAS-P while taking into consideration a trade-off between a measurement distance and an upper limit of a measurable vibrational frequency. When a phase change of an arbitrary section of a measured optical fiber is represented by A×sin (2πfvt), N=4Zfv/ν is satisfied when A is smaller than π/2 but N=2Zfv/(ν·Arcsin (π/2A)) is satisfied when A is equal to or larger than π/2, where fv represents vibrational frequency, t represents time, Z represents a length of the measured optical fiber (a measurement distance), and ν represents the speed of light inside the measured optical fiber.
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Patent Agency Ranking
公开(公告)号：US20220299401A1
公开(公告)日：2022-09-22
申请号：US17636093
申请日：2019-08-23
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Nazuki HONDA , Kazutaka NOTO , Hiroyuki OSHIDA
IPC: G01M11/02 , H04B10/071
Abstract: An object of the present invention is to provide an optical fiber test method, an optical fiber test apparatus, and a program, capable of detecting a boundary of an optical fiber line facility regardless of a change in a noise amount. A change amount (a differential value) of an OTDR waveform increases toward a distal end due to noise effects, making it difficult to determine a boundary of the optical fiber using the change amount. Therefore, in the present invention, a dispersion of the OTDR waveform, which increases toward a distal end due to noise effects, is also used to determine the boundary of the optical fiber. In other words, in the present invention, the noise amount is expressed by the dispersion, and the dispersion is compared with the change amount such as a differential value as a threshold, to determine the boundary of the optical fiber. For this reason, when noise increases, the threshold increases together with an increase in the change amount, and therefore, the boundary of the optical fiber can be determined regardless of noise.
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37.发明申请公开(公告)号：US20220260454A1
公开(公告)日：2022-08-18
申请号：US17622977
申请日：2019-07-11
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Tomokazu ODA , Yoshifumi WAKISAKA , Daisuke IIDA , Hiroyuki OSHIDA
IPC: G01M11/02 , G01M11/00 , H04B10/073
Abstract: An object is to provide a light intensity distribution measurement method and a light intensity distribution measurement apparatus that are capable of accurately measuring the intensity of light in each mode at each position of an optical fiber through which light is propagated in a plurality of modes. With a light intensity distribution measurement apparatus according to the present invention, a gain coefficient matrix is acquired in advance, which is constituted by Brillouin gain coefficients of propagation modes with predetermined optical frequency differences measured using a reference optical fiber that exhibits the same properties as a measurement-target optical fiber and that does not cause mode coupling, and the intensity distribution of light in each propagation mode in a lengthwise direction of the measurement-target optical fiber is calculated based on the gain coefficient matrix and a difference in light intensity before and after Brillouin amplification of the probe light emitted in a predetermined propagation mode at a predetermined optical frequency difference measured using the measurement-target optical fiber.
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公开(公告)号：US20220221314A1
公开(公告)日：2022-07-14
申请号：US17595065
申请日：2019-05-21
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Yoshifumi WAKISAKA , Daisuke IIDA , Keiji OKAMOTO , Hiroyuki OSHIDA
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.-
39.发明申请公开(公告)号：US20220172389A1
公开(公告)日：2022-06-02
申请号：US17437887
申请日：2020-03-18
Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Inventor： Masaaki INOUE , Tomoya SHIMIZU , Ryuji HONDA , Hiroyuki OSHIDA
Abstract: A structure detection device according to an embodiment includes: a reading processing unit that reads, as three-dimensional point group data on an object present in a three-dimensional space, data including three-dimensional position information and color information at a point on a surface of the object; a filtering processing unit that performs filtering processing for extracting three-dimensional point group data on a detection-target structure from the three-dimensional point group data on the object present in the three-dimensional space based on the color information; and a generation processing unit that generates three-dimensional model data in which the detection-target structure is represented as a three-dimensional model based on the three-dimensional point group data on the detection-target structure, the three-dimensional point group data being extracted by the filtering processing unit.
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公开(公告)号：US20220103252A1
公开(公告)日：2022-03-31
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: H04B10/071 , H04B10/27 , H04B10/2507
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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