公开(公告)号：US20170264365A1

公开(公告)日：2017-09-14

申请号：US15529145

申请日：2015-11-18

Applicant: NEC Corporation

Inventor： Seigo TAKAHASHI ,  Toshiharu ITO ,  Akihiro TANAKA ,  Kohei HOSOKAWA ,  Manabu ARIKAWA

IPC: H04B10/118 ,  H04B10/548 ,  H04B10/112 ,  H04B10/2581 ,  H04B10/67

CPC classification number: H04B10/118 ,  H04B10/112 ,  H04B10/2581 ,  H04B10/548 ,  H04B10/676

Abstract: It is difficult in a free space optical receiver to satisfy both of the stable receiving and the highly sensitive receiving; therefore, a free space optical receiver according to an exemplary aspect of the present invention includes a light collecting means for collecting laser light having propagated through a free space transmission path; a multimode light generating means for receiving input of the laser light collected by the light collecting means, exciting multimode light, and outputting multimode propagation light including a plurality of propagation mode light beams with a number smaller than a number of multimode light beams possible to be excited; and a mode separating means for separating the multimode propagation light into the plurality of propagation mode light beams and outputting the plurality of propagation mode light beams.

公开(公告)号：US20170207850A1

公开(公告)日：2017-07-20

申请号：US15327862

申请日：2015-07-17

Applicant: NEC Corporation

Inventor： Seigo TAKAHASHI ,  Toshiharu ITO ,  Kohei HOSOKAWA

IPC: H04B10/112 ,  H04B10/60

CPC classification number: H04B10/112 ,  H04B10/60

Abstract: The circuit size of a signal processing circuit increases in a free space optical receiver, which increases in cost, because the signal processing becomes complex attempting to improve the coupling efficiency between received light and a fiber; therefore, a free space optical receiver according to an exemplary aspect of the present invention includes a light collecting means for collecting laser light having propagated through a free space transmission path; a multi-mode transmission medium for receiving input of the laser light and outputting multi-mode light; a multi-mode signal processing means for outputting a plurality of received electrical signals based on part of the multi-mode light; a monitor means for monitoring signal information based on the multi-mode light; a control means for controlling an operation of the multi-mode signal processing means based on the signal information; and a signal processing means for performing signal processing on the plurality of received electrical signals and outputting an output signal synthesized from the plurality of received electrical signals.

公开(公告)号：US20180323904A1

公开(公告)日：2018-11-08

申请号：US15773035

申请日：2016-11-01

Applicant: NEC CORPORATION

Inventor： Kohei HOSOKAWA ,  Toshiharu ITO ,  Manabu ARIKAWA ,  Seigo TAKAHASHI ,  Takashi ISHIKAWA ,  Yoshimasa ONO

IPC: H04L1/00 ,  H04L27/22 ,  H04B10/61 ,  H04B10/118 ,  H04L27/00

CPC classification number: H04L1/0057 ,  H04B10/118 ,  H04B10/61 ,  H04L27/0014 ,  H04L27/22 ,  H04L2027/0057

Abstract: An appropriate synthesized signal cannot be obtained by only correcting relative phase errors of a plurality of received signals; therefore, a received signal processor according to an exemplary aspect of the present invention includes a plurality of signal-to-noise ratio estimation means for estimating respective signal-to-noise ratios of a plurality of digital signal sequences in which relative phase errors of a plurality of received signal sequences having been corrected; a plurality of temporary decision means for performing symbol decisions of the plurality of digital signal sequences and outputting symbol signal sequences; symbol-map-rotation determination means for determining respective phase rotation amounts of the plurality of digital signal sequences from the plurality of symbol signal sequences and the respective signal-to-noise ratios of the plurality of digital signal sequences; and a plurality of phase rotation means for rotating phases of the plurality of digital signal sequences respectively based on the phase rotation amounts.

公开(公告)号：US20200304213A1

公开(公告)日：2020-09-24

申请号：US16088328

申请日：2017-03-17

Applicant: NEC Corporation

Inventor： Kohei HOSOKAWA ,  Toshiharu ITO ,  Seigo TAKAHASHI ,  Manabu ARIKAWA ,  Takashi ISHIKAWA ,  Yoshimasa ONO

IPC: H04B10/69 ,  H04B10/11 ,  H04B17/336

Abstract: The objective of the present invention is to reduce the size of a receiving device circuit in an optical space communication system while maintaining communication stability. A data receiving device which decodes one item of data from a plurality of input signals includes: two or more digital signal processing means for subjecting the plurality of input signals to signal processing; a first recording means for temporarily recording the plurality of input signals; a SN ratio estimating means for estimating S/N ratios of each of the plurality of input signals and determining the number of the plurality of input signals to be combined, and the signals to be combined; and a scheduling means for carrying out overall control on the basis of the results from the SN ratio estimating means.

公开(公告)号：US20180234180A1

公开(公告)日：2018-08-16

申请号：US15751369

申请日：2016-08-17

Applicant: NEC CORPORATION

Inventor： Seigo TAKAHASHI ,  Toshiharu ITO ,  Kohei HOSOKAWA ,  Manabu ARIKAWA ,  Yoshimasa ONO ,  Takashi ISHIKAWA

IPC: H04B10/116 ,  H04B10/50 ,  H04B10/61

CPC classification number: H04B10/116 ,  H04B10/1121 ,  H04B10/118 ,  H04B10/50 ,  H04B10/61

Abstract: It is difficult in a free space optical transmitter to transmit a beacon beam stably at low cost, and that it is impossible to maintain stable tracking; therefore, a free space optical transmitter according to an exemplary aspect of the present invention includes a laser beam transmitting means for transmitting a plurality of laser beams capable of interfering with each other and differing in one of an optical frequency and a time variation in a phase difference; and a wavefront control beam transmitting means for transmitting, to a free space, a plurality of wavefront control beams obtained by making each of the plurality of laser beams have a different wavefront.

公开(公告)号：US20180212681A1

公开(公告)日：2018-07-26

申请号：US15745254

申请日：2016-07-15

Applicant: NEC CORPORATION

Inventor： Akihiro TANAKA ,  Toshiharu ITO ,  Kohei HOSOKAWA ,  Seigo TAKAHASHI ,  Manabu ARIKAWA

IPC: H04B10/118 ,  H04B10/00

CPC classification number: H04B10/118 ,  H04B10/112 ,  H04B10/12 ,  H04B10/40 ,  H04B10/50 ,  H04B10/60

Abstract: A receiving-side splitter 4 that constitutes part of an optical communication device 1 splits a receiving-side signal light into a plurality of lights at a splitting ratio according to the intensity distribution of mutually different propagation modes included in the receiving-side signal light passed through a transmission medium 3. A transmission-side splitter 10 splits a transmission-side signal light into a plurality of-lights. A signal processing device 5 detects the light intensity and/or the phase of the receiving-side signal light, and sets a control target value for the light intensity and/or the phase of the transmission-side signal light to a value according to the result of the detection. A modulator 9 adjusts the light intensity or the phase of a the transmission-side signal light so that the light intensity or phase equals the set value. A multiplexer 8 multiplexes the plurality of transmission-side signal lights.

公开(公告)号：US20170070289A1

公开(公告)日：2017-03-09

申请号：US15123103

申请日：2014-03-13

Applicant: NEC Corporation

Inventor： Seigo TAKAHASHI ,  Toshiharu ITO ,  Kohei HOSOKAWA

IPC: H04B10/112 ,  H04B10/60

CPC classification number: H04B10/1121 ,  H04B10/60 ,  H04J14/02

Abstract: It is impossible to prevent the deterioration of the coupling efficiency between received light and a single mode fiber, and difficult to achieve a higher transmission rate, with respect to a free space optical communication receiver; therefore, a free space optical receiver according to an exemplary aspect of the present invention includes light collecting means for collecting laser light having propagated through a free space transmission path; mode controlling means for separating the laser light collected by the light collecting means into a plurality of propagation mode beams depending on a wave-front fluctuation of the laser light and outputting the propagation mode beams; a plurality of single mode transmission media for guiding the plurality of propagation mode beams, respectively; and a plurality of light receiving means for receiving the plurality of propagation mode beams respectively through the plurality of single mode transmission media.

Abstract translation: 相对于自由空间光通信接收机，不可能防止接收光和单模光纤之间的耦合效率的劣化，难以实现更高的传输速率; 因此，根据本发明的示例性方面的自由空间光学接收器包括：聚光装置，用于收集通过自由空间传播路径传播的激光; 模式控制装置，用于根据激光的波前波动将由光收集装置收集的激光分离成多个传播模式光束，并输出传播模式光束; 分别引导多个传播模式波束的多个单模传输介质; 以及多个光接收装置，用于分别通过多个单模传输介质接收多个传播模式光束。