Patents by Inventor Hiroki Kawahara

Hiroki Kawahara has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11979226
    Abstract: A wavelength cross-connect device performs relay processing, the relay processing being such that wavelength multiplexed signal lights, which are multiband transmitted from a plurality of routes, are demultiplexed into different wavelength bands, and for each route, respective optical signals of the different wavelength bands are amplified, then subject to route change by WSSs and outputted to output side routes M. The device includes C-band WXC units that are the same in total number as the wavelength bands of the optical signals of the respective wavelength bands and perform relay processing on optical signals of a specific wavelength band of the different wavelength bands.
    Type: Grant
    Filed: February 4, 2020
    Date of Patent: May 7, 2024
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Hiroki Kawahara, Takeshi Seki, Sachio Suda, Kohei Saito, Kenta Hirose
  • Patent number: 11824583
    Abstract: A cyclic wavelength band permutation device (31) includes as many wavelength band converters (32a to 32c) as the wavelength bands of optical signals (S1, C1, and L1), and the wavelength band converters are individually connected to the output terminals of corresponding optical amplifiers among a plurality of optical amplifiers (17a to 17c) connected to an optical fiber (16) in an inserted manner. When a wavelength-multiplexed signal beam obtained by multiplexing optical signals in different wavelength bands is multiband-transmitted through an optical fiber while being amplified by the plurality of optical amplifiers, each wavelength band converter performs a cyclic permutation process of transitioning or converting an optical signal allocated to the shorter wavelength band side in the bands of the optical fiber to the longer wavelength band side, and also transitioning or converting an optical signal allocated to the longest wavelength band to the shortest wavelength band.
    Type: Grant
    Filed: February 4, 2020
    Date of Patent: November 21, 2023
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Hiroki Kawahara, Takeshi Seki, Sachio Suda, Kohei Saito, Kenta Hirose
  • Patent number: 11812205
    Abstract: A monitoring control unit (22) of an OXC (20d) stores a management table (22a) in which pieces of information regarding a modulation mode, an FEC, and a frame mode of an optical signal are associated with each other, and sequentially changes the modulation mode, the FEC, and the frame mode according to the management table (22a) upon an LOS alert from a relay-side optical input/output unit (24) or an LOF alert from a DSP (25) being input thereto. Upon successfully receiving an appropriate optical signal according to the change, the monitoring control unit (22) acquires transmission source information included in the optical signal, and detects an occurrence of erroneous connection of an optical transmission line in an OXC (20g), which serves as a relay apparatus, when the acquired transmission source information indicates an optical cross-connect apparatus that is a transmission source different from an original transmission source.
    Type: Grant
    Filed: July 12, 2019
    Date of Patent: November 7, 2023
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Masatoshi Namiki, Masahiro Yokota, Hiroki Kawahara, Hiroto Takechi, Katsuhiro Araya, Masaaki Inami, Daisaku Shimazaki, Hideki Maeda
  • Patent number: 11750317
    Abstract: The present invention is to provide a wavelength cross-connect device that reduces device costs. A wavelength cross-connect device 10B performs relaying for changing, using WSSs, routes of optical signals transmitted from M routes 1h to Mh, in which K optical fibers 1f to Kf are grouped for each of the routes, on an input side to output the optical signals to respective optical fibers 1f to Kf of M routes 1h to Mh on an output side. Input ports of each of the optical couplers 25a to 26d are connected to output ports of each of first WSSs 21a to 22k.
    Type: Grant
    Filed: March 9, 2020
    Date of Patent: September 5, 2023
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Hiroki Kawahara, Takeshi Seki
  • Publication number: 20230275668
    Abstract: A wavelength cross-connect device is formed by connecting a plurality of wavelength cross-connect devices in a ring-like form with WDM networks for each band of a plurality of bands on the input/output sides of the wavelength cross-connect devices, and includes a link wavelength allocation control unit. The link wavelength allocation control unit performs control to set different optical paths through which optical signals of the same wavelength are transmitted in the same zone between wavelength cross-connect devices, in the WDM networks of different bands in the same zone.
    Type: Application
    Filed: July 6, 2020
    Publication date: August 31, 2023
    Inventors: Hiroki KAWAHARA, Takeshi SEKI, Sachio SUDA, Kohei SAITO
  • Publication number: 20230275667
    Abstract: A wavelength cross-connect device performs a relay process in which multiple wavelength signal light beams that have been transmitted in multiple bands from a plurality of paths and demultiplexed into optical signals in the respective wavelength bands for each path are amplified, are switched to paths by contention WSSs, and are output to paths on the output side. A WXC unit performs the relay process on an optical signal in a specific wavelength band An input-side conversion unit that converts a wavelength band other than the specific wavelength band into the specific wavelength band is provided on the input side, and an output-side conversion unit that converts the specific wavelength band after the conversion into the wavelength band prior to the conversion is provided on the output side. A directly-input optical signal in the specific wavelength band is directly output after the relay process at the WXC unit.
    Type: Application
    Filed: July 6, 2020
    Publication date: August 31, 2023
    Inventors: Hiroki KAWAHARA, Takeshi SEKI, Sachio SUDA, Kohei SAITO
  • Publication number: 20230268998
    Abstract: Provided is an optical transmission system that includes: a transponder having a transmitter and a receiver; a loopback path that directly couples a signal of the transmitter to the receiver; and a server that calculates, based on a signal transmitted using the loopback path, a compensation value to compensate for frequency characteristics of a signal transmitted from the transmitter.
    Type: Application
    Filed: July 2, 2020
    Publication date: August 24, 2023
    Inventors: Kohei SAITO, Takeshi SEKI, Sachio SUDA, Hiroki KAWAHARA, Kenta HIROSE, Hideki MAEDA
  • Publication number: 20230254611
    Abstract: An optical node device (1aA to 1cA) includes a transmission transponder (27), WSSs (22 to 25), a beam splitter (21), and a monitoring transponder (26). The transmission transponder (27) transmits an optical signal (B1) via an optical path (P3) set in an optical fiber (2). The WSSs (22 to 25) multiplex, on the transmitted optical signal (B1), a monitoring control signal (M1) for performing optical path tracing that is confirmation of conduction along the optical path (P3). The monitoring transponder (26) measures and monitors the optical power of the monitoring control signal (M1) multiplexed into the optical signal (B1) branched by the beam splitter (21), and further monitors whether the monitored optical power is equal to or higher than a predetermined level indicating normality of the optical path (P3).
    Type: Application
    Filed: July 6, 2020
    Publication date: August 10, 2023
    Inventors: Hiroki Kawahara, Takeshi SEKI, Sachio Suda, Kohei Saito
  • Patent number: 11722235
    Abstract: The present invention is to provide an optical add/drop multiplexing device capable of realizing a configuration in which many transponders can be connected at low cost. An optical add/drop multiplexing device 30A includes branch function units 34a to 34d connected to each of WSSs 22a to 22d connected to respective routes 1 to D having a plurality of optical fibers and dropping optical signals having a plurality of wavelengths among the optical signals having the respective wavelengths transmitted by wavelength division multiplexing. The optical add/drop multiplexing device includes C-function units 35a to 35d configured to transmit the optical signals branched by the branch function units 34a to 34d to a plurality of transponders.
    Type: Grant
    Filed: March 9, 2020
    Date of Patent: August 8, 2023
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Hiroki Kawahara, Takeshi Seki
  • Publication number: 20230244025
    Abstract: A multi-core fiber (23) connects an optical transmitter device (10) and an optical receiver device (30) to each other. The multi-core fiber (23) includes cores each having a wavelength dispersion characteristic different from a wavelength dispersion characteristic of another adjacent core of the cores. In an optical transport system (100), the optical transmitter device (10) and the optical receiver device (30) are connected in series by the plurality of multi-core fibers (23).
    Type: Application
    Filed: June 29, 2020
    Publication date: August 3, 2023
    Inventors: Kenta HIROSE, Kohei SAITO, Hiroki KAWAHARA, Sachio SUDA, Takeshi SEKI
  • Patent number: 11696056
    Abstract: [Problem] whether optical input interruption detected by an OXC device is due to an external failure from an upstream side or an internal failure of the OXC device in a transponder device connected to the OXC device using an optical transmission line, and this determination is implemented at low cost. [Solution] An optical transmission system (10A) is configured by connecting a plurality of OXC devices (14A) using optical fibers (16) between transponder devices (15A1) that relay optical signals transmitted to/from terminals (19a, 19b). The OXC device (14A) includes an OSC part (4d1) and a monitoring control part (4e1). The OSC part (4d1) outputs wavelength information on an optical signal in which optical input interruption has occurred and path information on a path of an optical fiber (16) in which the optical input interruption has occurred, at the time of detecting the optical input interruption from the optical fiber (16).
    Type: Grant
    Filed: February 13, 2020
    Date of Patent: July 4, 2023
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Hiroto Takechi, Katsuhiro Araya, Masatoshi Namiki, Hiroki Kawahara, Takeshi Seki
  • Patent number: 11677489
    Abstract: A large number of degrees for relays of optical signals transmitted via optical paths in the degrees is secured. A wavelength cross-connect device 20A performs a relay by splitting optical signals from respective degrees indicated by reference numerals 40l, 40h, 40m, 40q, each of the degrees being provided by optical fibers, via respective optical couplers and outputting the split optical signals to output sides of the plurality of degrees via respective WSSs 23a to 23d. As the optical couplers, variable couplers 27a to 27d whose respective splitting ratios, each of which is a ratio of optical signal power losses in splitting an optical signal, are variable are used. The wavelength cross-connect device 20A includes a control unit 26 that performs control to change the splitting ratios in such a manner as to eliminate an imbalance among OSNR margins of the output sides of the degrees in which a plurality of optical paths transmitting the split optical signals extend.
    Type: Grant
    Filed: March 9, 2020
    Date of Patent: June 13, 2023
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Hiroki Kawahara, Takeshi Seki
  • Publication number: 20230074213
    Abstract: A cyclic wavelength band permutation device (31) includes as many wavelength band converters (32a to 32c) as the wavelength bands of optical signals (S1, C1, and L1), and the wavelength band converters are individually connected to the output terminals of corresponding optical amplifiers among a plurality of optical amplifiers (17a to 17c) connected to an optical fiber (16) in an inserted manner. When a wavelength-multiplexed signal beam obtained by multiplexing optical signals in different wavelength bands is multiband-transmitted through an optical fiber while being amplified by the plurality of optical amplifiers, each wavelength band converter performs a cyclic permutation process of transitioning or converting an optical signal allocated to the shorter wavelength band side in the bands of the optical fiber to the longer wavelength band side, and also transitioning or converting an optical signal allocated to the longest wavelength band to the shortest wavelength band.
    Type: Application
    Filed: February 4, 2020
    Publication date: March 9, 2023
    Inventors: Hiroki Kawahara, Takeshi SEKI, Sachio Suda, Kohei Saito, Kenta Hirose
  • Publication number: 20230067932
    Abstract: A wavelength cross-connect device (20A) performs relay processing, the relay processing being such that wavelength multiplexed signal lights (1a to 1m), which are multiband transmitted from a plurality of routes M(1), are demultiplexed into different wavelength bands (S band, C band, and L band), and for each route, respective optical signals of the different wavelength bands (S band, C band, and L band) are amplified, then subject to rout change by WSSs and outputted to output side routes M(2). The device includes C-band WXC units 22 that are the same in total number as the wavelength bands of the optical signals of the respective wavelength bands and perform relay processing on optical signals of a specific wavelength band (C band) of the different wavelength bands.
    Type: Application
    Filed: February 4, 2020
    Publication date: March 2, 2023
    Inventors: Hiroki Kawahara, Takeshi SEKI, Sachio Suda, Kohei Saito, Kenta Hirose
  • Publication number: 20220416897
    Abstract: An optical amplifier (21) configured to operate with saturated output power is coupled on the receive side with respect to a receiver (18) coupled to a transmitter (17) via an optical fiber (14). The saturated output power is represented as a saturation characteristic drawing a flat curve in which, as power (input optical power) of an optical signal (22i) inputted to the optical amplifier (21) increases in excess of a given level, the variation in power (output optical power) of an optical signal (22o) outputted from the optical amplifier (21) decreases. Consequently, information represented by the optical signal (22o) inputted from the optical amplifier (21) to the receiver (18) can be properly received.
    Type: Application
    Filed: June 21, 2019
    Publication date: December 29, 2022
    Inventors: Kohei Saito, Hiroki Kawahara, Takeshi SEKI, Hideki Maeda
  • Patent number: 11528080
    Abstract: [Problem] In an optical transmission system, a position and a cause of a failure are identified while avoiding tightness of processing on a network controller side. [Solution] An optical transmission system 1 includes a plurality of nodes 4i to 4k interconnected by an optical transmission line, a plurality of node controllers 3i to 3k that detect degradation of signal quality at the nodes 4i to 4k, respectively, and determine a degradation mode correlated with the signal quality, and a network controller 2 that identifies a node or a component in which failure has occurred based on a node for which the node controller 3i to 3k has detected degradation of the signal quality, the degradation mode, a network topology formed of the nodes, and an optical path set between the nodes.
    Type: Grant
    Filed: November 15, 2019
    Date of Patent: December 13, 2022
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Hiroki Kawahara, Toshiyuki Oka, Takeshi Seki, Toshihiko Seki
  • Publication number: 20220286762
    Abstract: A monitoring control unit (22) of an OXC (20d) stores a management table (22a) in which pieces of information regarding a modulation mode, an FEC, and a frame mode of an optical signal are associated with each other, and sequentially changes the modulation mode, the FEC, and the frame mode according to the management table (22a) upon an LOS alert from a relay-side optical input/output unit (24) or an LOF alert from a DSP (25) being input thereto. Upon successfully receiving an appropriate optical signal according to the change, the monitoring control unit (22) acquires transmission source information included in the optical signal, and detects an occurrence of erroneous connection of an optical transmission line in an OXC (20g), which serves as a relay apparatus, when the acquired transmission source information indicates an optical cross-connect apparatus that is a transmission source different from an original transmission source.
    Type: Application
    Filed: July 12, 2019
    Publication date: September 8, 2022
    Inventors: Masatoshi Namiki, Masahiro YOKOTA, Hiroki Kawahara, Hiroto TAKECHI, Katsuhiro Araya, Masaaki Inami, Daisaku Shimazaki, Hideki Maeda
  • Patent number: 11424824
    Abstract: An OSNR spectrum estimation apparatus includes an OSNR estimation unit configured to cause an optical node to estimate an OSNR of a predetermined transmission line using a probe light of a predetermined wavelength in a predetermined number of wavelength channels, the predetermined number being less than the number of all wavelength channels; and an OSNR spectrum calculation unit configured to calculate an OSNR spectrum of all the wavelength channels from OSNRs of the predetermined number of wavelength channels measured by the optical node.
    Type: Grant
    Filed: August 14, 2019
    Date of Patent: August 23, 2022
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Hiroki Kawahara, Kohei Saito, Takeshi Seki, Tsutomu Kubo
  • Patent number: 11379801
    Abstract: A maintenance support system for a plurality of maintenance-target apparatus in a plant includes a maintenance information delivery unit that delivers maintenance information Im that indicates an operational status of each maintenance-target apparatus to maintenance personnel every preset time T, wherein the maintenance information delivery unit delivers predictive information If to the maintenance personnel at a specified time Tf between the previous delivery of the maintenance information Im and the next delivery of the maintenance information Im, the predictive information If providing predictions regarding the operational status of each maintenance-target apparatus at the next delivery of the maintenance information Im.
    Type: Grant
    Filed: February 15, 2016
    Date of Patent: July 5, 2022
    Assignee: TLV Co., Ltd.
    Inventors: Yoshiyasu Fujiwara, Kazunori Oda, Yoshio Miyamae, Hiroki Kawahara
  • Patent number: 11362894
    Abstract: When separate service apparatuses that provide various communication services to users are connected by a wiring with communication functional units interposed, if there is a wiring abnormality, the location of the abnormality is easily identified. When a wiring connection is completed between separated service apparatuses X and Y that provide various communication services to user terminals 31 and 32 with communication functional units A1 and B2 interposed, a wiring management system 10A includes a transmission network management apparatus 14A that identifies a wiring abnormality. The transmission network management apparatus 14A associates endpoint names of the service apparatuses X and Y and of the functional units A1 and B2 with opposite endpoint names on the opposite sides, defines opposite endpoint IDs of the endpoints of the functional units A1 and B2 as expected values, and saves the end points in association with the opposite endpoint IDs in a DB 14b.
    Type: Grant
    Filed: March 19, 2019
    Date of Patent: June 14, 2022
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Yoshihiko Uematsu, Hiroshi Yamamoto, Hiroki Kawahara, Katsuhiro Araya, Toshiyuki Oka