Patents by Inventor Shinsuke Fujisawa
Shinsuke Fujisawa 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).
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Patent number: 11212027Abstract: This optical path setting device comprises: a transmission characteristic calculating means for calculating an inter-endpoint transmission characteristic that is a characteristic for transmission between endpoints of an optical path accommodating traffic in a plurality of optical communication systems; a required wavelength bandwidth determining means for determining a required wavelength bandwidth that is a wavelength bandwidth meeting an arrival performance of the optical path on the basis of the inter-endpoint transmission characteristic; and an accommodating wavelength band determining means for determining, as an accommodating wavelength band for accommodating the optical path, a common wavelength band that is a wavelength band where an optical path having the required wavelength bandwidth can be allocated, and that is common to the plurality of optical communication systems.Type: GrantFiled: November 29, 2018Date of Patent: December 28, 2021Assignee: NEC CORPORATIONInventors: Shinsuke Fujisawa, Hitoshi Takeshita, Shigeyuki Yanagimachi, Emmanuel Le Taillandier De Gabory
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Patent number: 11201668Abstract: If wavelength defragmentation is performed during the operation of an optical network, an instantaneous interruption of a network arises; consequently, data are lost; therefore, an optical network control method according to an exemplary aspect of the present invention includes monitoring a data volume of a client signal to be transmitted using a plurality of optical subcarriers; and performing synchronously, depending on a variation in the data volume, an optical subcarrier changing process of changing an active optical subcarrier, of the plurality of optical subcarriers, to be used for transmitting the client signal, and a remapping process of remapping the client signal onto an active optical subcarrier after having been changed.Type: GrantFiled: June 17, 2020Date of Patent: December 14, 2021Assignee: NEC CORPORATIONInventors: Tomoyuki Hino, Akio Tajima, Hitoshi Takeshita, Shinsuke Fujisawa
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Publication number: 20210356316Abstract: Aspects of the present disclosure are directed to alternative repeater design(s) that advantageously improve signal-to-noise of distributed acoustic sensing (DAS) systems using coherent detection of Rayleigh backscatter in multi-span links including inline amplification that may be employed—for example—in undersea submarine systems. The repeater designs incorporate Rayleigh combine units (RCU) and Rayleigh drop units (RDU) to reduce Rayleigh backscatter loss as Rayleigh signal(s) is/are routed to a link that propagates the backscatter signal in an opposite direction relative to interrogation pulse(s).Type: ApplicationFiled: May 6, 2021Publication date: November 18, 2021Applicant: NEC LABORATORIES AMERICA, INCInventors: Ezra IP, Yue-Kai HUANG, Fatih YAMAN, Shinsuke FUJISAWA
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Publication number: 20210352386Abstract: It is difficult to improve the usage efficiency of an optical communication network due to the passband narrowing effect in a wavelength selection process in an optical communication network using a wavelength division multiplexing system; therefore, an optical network management apparatus according to an exemplary aspect of the present invention includes wavelength selection information generating means for generating wavelength selection information on a wavelength selection process through which an optical path accommodating an information signal goes, with respect to each optical path; and wavelength selection information notifying means for notifying an optical node device through which the optical path goes of the wavelength selection information.Type: ApplicationFiled: July 26, 2021Publication date: November 11, 2021Applicant: NEC CORPORATIONInventors: Hitoshi Takeshita, Shinsuke Fujisawa, Tomoyuki Hino, Akio Tajima
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Patent number: 11115117Abstract: A submarine optical communication system control device (1) according to the present invention includes: a light intensity distribution determination device (2) configured to determine an optimum distribution of signal light intensity of each optical path for each allocated frequency; a light intensity distribution measuring device (3) configured to measure a light intensity distribution of an optical path after transmission through a submarine cable transmission line; an equalization setting calculation unit (4) configured to calculate a gain equalization setting for compensating for the difference between an optimum distribution in the light intensity distribution determination device and a measured distribution in the light intensity distribution measuring device; and a variable gain equalizer (5) configured to compensate for a light intensity distribution of an optical path to the optimum distribution, based on a gain equalization setting in the equalization setting calculation unit.Type: GrantFiled: March 27, 2018Date of Patent: September 7, 2021Assignee: NEC CORPORATIONInventors: Shinsuke Fujisawa, Hitoshi Takeshita, Shigeyuki Yanagimachi, Emmanuel Le Taillandier De Gabory
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Patent number: 11115318Abstract: An optical network control device includes: a path setting unit that sets, based on topology information including a connection relationship among a plurality of nodes and a first route selection index value of routes each connecting the plurality of nodes, a first path for a route having the first route selection index value being minimum from among route candidates linking a start point node and an end point node of a requested traffic; a topology information modification unit that calculates a second route selection index value acquired by increasing the first route selection index value of the route that accommodates the first path; and a path selection unit that selects a second path for a route having the second route selection index value being minimum from among the route candidates.Type: GrantFiled: October 4, 2017Date of Patent: September 7, 2021Assignee: NEC CORPORATIONInventors: Shinsuke Fujisawa, Hitoshi Takeshita, Akio Tajima
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Patent number: 11109123Abstract: It is difficult to improve the usage efficiency of an optical communication network due to the passband narrowing effect in a wavelength selection process in an optical communication network using a wavelength division multiplexing system; therefore, an optical network management apparatus according to an exemplary aspect of the present invention includes wavelength selection information generating means for generating wavelength selection information on a wavelength selection process through which an optical path accommodating an information signal goes, with respect to each optical path; and wavelength selection information notifying means for notifying an optical node device through which the optical path goes of the wavelength selection information.Type: GrantFiled: July 9, 2020Date of Patent: August 31, 2021Assignee: NEC CORPORATIONInventors: Hitoshi Takeshita, Shinsuke Fujisawa, Tomoyuki Hino, Akio Tajima
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Publication number: 20210256347Abstract: Aspects of the present disclosure describe optical transmission systems exhibiting low complexity fiber nonlinearity compensation provided by neural networks using lookup tables for multiplication operations.Type: ApplicationFiled: January 12, 2021Publication date: August 19, 2021Applicant: NEC LABORATORIES AMERICA, INCInventors: Shinsuke FUJISAWA, Fatih YAMAN, Eduardo Mateo RODRIGUEZ, Yoshihisa INADA, Kohei NAKAMURA, Takanori INOUE
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Patent number: 10938499Abstract: It is difficult in the elastic optical network to achieve a balance between the improvement in the frequency utilization efficiency and the increase in the probability of opening an optical path; therefore, an optical path controller according to an exemplary aspect of the present invention includes route selection means for searching for a route candidate being a candidate for a route to accommodate an optical path, and selecting a best possible route with a minimum route selection index serving as an index for route search; use rate collecting means for collecting a use rate serving as an index to indicate a usage condition of an optical frequency band in an optical fiber transmission line included in the route candidate; and route selection index judgment means for determining the route selection index based on the use rate.Type: GrantFiled: July 6, 2017Date of Patent: March 2, 2021Assignee: NEC CorporationInventors: Shinsuke Fujisawa, Akio Tajima, Hitoshi Takeshita
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Publication number: 20210058157Abstract: In a multi-layer network, a control load in the upper layer network increases, and the usage efficiency and the reliability of the entire network decrease; therefore, a multi-layer network system according to an exemplary aspect of the present invention includes a first network manager configured to set a logical path in a first network layer; and a second network manager configured to set a physical path corresponding to the logical path, in a second network layer, wherein the second network manager includes a network information storage configured to store physical network information including physical route information and transmission characteristic information on the second network layer, and the first network manager sets the logical path based on the physical network information.Type: ApplicationFiled: November 6, 2020Publication date: February 25, 2021Applicant: NEC CorporationInventors: Hitoshi TAKESHITA, Shinsuke FUJISAWA, Tomoyuki HINO, Akio TAJIMA
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Publication number: 20210013965Abstract: A submarine optical communication system control device (1) according to the present invention includes: a light intensity distribution determination device (2) configured to determine an optimum distribution of signal light intensity of each optical path for each allocated frequency; a light intensity distribution measuring device (3) configured to measure a light intensity distribution of an optical path after transmission through a submarine cable transmission line; an equalization setting calculation unit (4) configured to calculate a gain equalization setting for compensating for the difference between an optimum distribution in the light intensity distribution determination device and a measured distribution in the light intensity distribution measuring device; and a variable gain equalizer (5) configured to compensate for a light intensity distribution of an optical path to the optimum distribution, based on a gain equalization setting in the equalization setting calculation unit.Type: ApplicationFiled: March 27, 2018Publication date: January 14, 2021Applicant: NEC CORPORATIONInventors: Shinsuke FUJISAWA, Hitoshi TAKESHITA, Shigeyuki YANAGIMACHI, Emmanuel LE TAILLANDIER DE GABORY
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Publication number: 20200403383Abstract: Aspects of the present disclosure describe systems, methods and structures for providing semiconductor amplifiers exhibiting a low polarization-dependent gain.Type: ApplicationFiled: June 17, 2020Publication date: December 24, 2020Applicant: NEC LABORATORIES AMERICA, INCInventors: Fatih YAMAN, Shinsuke FUJISAWA, Eduardo Mateo RODRIGUEZ, Kohei NAKAMURA, Takanori INOUE, Yoshihisa INADA, Takaaki OGATA
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Publication number: 20200374607Abstract: This optical path setting device comprises: a transmission characteristic calculating means for calculating an inter-endpoint transmission characteristic that is a characteristic for transmission between endpoints of an optical path accommodating traffic in a plurality of optical communication systems; a required wavelength bandwidth determining means for determining a required wavelength bandwidth that is a wavelength bandwidth meeting an arrival performance of the optical path on the basis of the inter-endpoint transmission characteristic; and an accommodating wavelength band determining means for determining, as an accommodating wavelength band for accommodating the optical path, a common wavelength band that is a wavelength band where an optical path having the required wavelength bandwidth can be allocated, and that is common to the plurality of optical communication systems.Type: ApplicationFiled: November 29, 2018Publication date: November 26, 2020Applicant: NEC CORPORATIONInventors: Shinsuke FUJISAWA, Hitoshi TAKESHITA, Shigeyuki YANAGIMACHI, Emmanuel LE TAILLANDIER DE GABORY
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Patent number: 10848245Abstract: In a multi-layer network, a control load in the upper layer network increases, and the usage efficiency and the reliability of the entire network decrease; therefore, a multi-layer network system according to an exemplary aspect of the present invention includes a first network manager configured to set a logical path in a first network layer; and a second network manager configured to set a physical path corresponding to the logical path, in a second network layer, wherein the second network manager includes a network information storage configured to store physical network information including physical route information and transmission characteristic information on the second network layer, and the first network manager sets the logical path based on the physical network information.Type: GrantFiled: December 15, 2015Date of Patent: November 24, 2020Assignee: NEC CORPORATIONInventors: Hitoshi Takeshita, Shinsuke Fujisawa, Tomoyuki Hino, Akio Tajima
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Patent number: 10848262Abstract: In an optical communication network using the wavelength division multiplexing system, the accommodation efficiency for the optical paths decreases, and it becomes difficult to use the optical communication network efficiently, if the optical frequency slots are used concentrically in a specific optical fiber; therefore, an optical path design apparatus according to an exemplary aspect of the present invention includes route candidate selection means for searching for a route of an optical path to accommodate a communication demand and selecting a plurality of route candidates; optical path candidate selection means for selecting a plurality of optical path candidates by allocating an optical frequency band required to accommodate the optical path to each of optical fibers on the plurality of route candidates; and optical path determination means for determining the optical path from among the plurality of optical path candidates based on an optical frequency band utilization rate in the optical fibers.Type: GrantFiled: September 20, 2017Date of Patent: November 24, 2020Assignee: NEC CORPORATIONInventors: Hitoshi Takeshita, Shinsuke Fujisawa, Akio Tajima
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Publication number: 20200344533Abstract: It is difficult to improve the usage efficiency of an optical communication network due to the passband narrowing effect in a wavelength selection process in an optical communication network using a wavelength division multiplexing system; therefore, an optical network management apparatus according to an exemplary aspect of the present invention includes wavelength selection information generating means for generating wavelength selection information on a wavelength selection process through which an optical path accommodating an information signal goes, with respect to each optical path; and wavelength selection information notifying means for notifying an optical node device through which the optical path goes of the wavelength selection information.Type: ApplicationFiled: July 9, 2020Publication date: October 29, 2020Applicant: NEC CORPORATIONInventors: Hitoshi TAKESHITA, Shinsuke FUJISAWA, Tomoyuki HINO, Akio TAJIMA
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Publication number: 20200313765Abstract: If wavelength defragmentation is performed during the operation of an optical network, an instantaneous interruption of a network arises; consequently, data are lost; therefore, an optical network control method according to an exemplary aspect of the present invention includes monitoring a data volume of a client signal to be transmitted using a plurality of optical subcarriers; and performing synchronously, depending on a variation in the data volume, an optical subcarrier changing process of changing an active optical subcarrier, of the plurality of optical subcarriers, to be used for transmitting the client signal, and a remapping process of remapping the client signal onto an active optical subcarrier after having been changed.Type: ApplicationFiled: June 17, 2020Publication date: October 1, 2020Applicant: NEC CorporationInventors: Tomoyuki HINO, Akio TAJIMA, Hitoshi TAKESHITA, Shinsuke FUJISAWA
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Patent number: 10750259Abstract: It is difficult to improve the usage efficiency of an optical communication network due to the passband narrowing effect in a wavelength selection process in an optical communication network using a wavelength division multiplexing system; therefore, an optical network management apparatus according to an exemplary aspect of the present invention includes wavelength selection information generating means for generating wavelength selection information on a wavelength selection process through which an optical path accommodating an information signal goes, with respect to each optical path; and wavelength selection information notifying means for notifying an optical node device through which the optical path goes of the wavelength selection information.Type: GrantFiled: June 18, 2019Date of Patent: August 18, 2020Assignee: NEC CORPORATIONInventors: Hitoshi Takeshita, Shinsuke Fujisawa, Tomoyuki Hino, Akio Tajima
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Patent number: 10715249Abstract: If wavelength defragmentation is performed during the operation of an optical network, an instantaneous interruption of a network arises; consequently, data are lost; therefore, an optical network control method according to an exemplary aspect of the present invention includes monitoring a data volume of a client signal to be transmitted using a plurality of optical subcarriers; and performing synchronously, depending on a variation in the data volume, an optical subcarrier changing process of changing an active optical subcarrier, of the plurality of optical subcarriers, to be used for transmitting the client signal, and a remapping process of remapping the client signal onto an active optical subcarrier after having been changed.Type: GrantFiled: March 18, 2016Date of Patent: July 14, 2020Assignee: NEC CORPORATIONInventors: Tomoyuki Hino, Akio Tajima, Hitoshi Takeshita, Shinsuke Fujisawa
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Publication number: 20200136743Abstract: It is difficult in the elastic optical network to achieve a balance between the improvement in the frequency utilization efficiency and the increase in the probability of opening an optical path; therefore, an optical path controller according to an exemplary aspect of the present invention includes route selection means for searching for a route candidate being a candidate for a route to accommodate an optical path, and selecting a best possible route with a minimum route selection index serving as an index for route search; use rate collecting means for collecting a use rate serving as an index to indicate a usage condition of an optical frequency band in an optical fiber transmission line included in the route candidate; and route selection index judgment means for determining the route selection index based on the use rate.Type: ApplicationFiled: July 6, 2017Publication date: April 30, 2020Applicant: NEC CorporationInventors: Shinsuke FUJISAWA, Akio TAJIMA, Hitoshi TAKESHITA