Optical communication device, optical communication system, and optical communication method

Patent metadata

Field	Value
Publication number	US-10411802-B2
Application number	US-201615745254-A
Country	US
Kind code	B2
Filing date	Jul 15, 2016
Priority date	Jul 17, 2015
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

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.

First claim

The invention claimed is:

1. An optical communication device comprising:
a transmission medium of a multimode type that transmits a reception-side signal light incident through a free space;
a reception-side multimode demultiplexer that distributes the reception-side signal light into a plurality of distributed reception-side signal lights at a distribution ratio, the distribution ratio being ratio depending on an intensity distribution of a plurality of mutually different propagation modes included in the reception-side signal light which has passed through the transmission medium;
a transmission-side demultiplexer that distributes a transmission-side signal light to be transmitted into a plurality of distributed transmission-side signal lights;
a signal processing device that includes a detection function and a setting function, the detection function being a function that detects either or both of a light intensity and a phase in each distributed reception-side signal light, the setting function being a function that sets a control target value for either or both of a light intensity and a phase to be controlled in each distributed transmission-side signal light to a value depending on a detection result by the detection function;
a modulator that adjusts either or both of a light intensity and a phase to be controlled in the distributed transmission-side signal light to the control target value set by the signal processing device; and
a multimode multiplexer that multiplexes the plurality of distributed transmission-side signal lights obtained after being adjusted by the modulator.

2. The optical communication device according to claim 1 , wherein the signal processing device sets the control target value in such a way as to cause the distributed transmission-side signal light to be in a phase-conjugated state with the reception-side signal light.

3. The optical communication device according to claim 1 , wherein the signal processing device detects either or both of the light intensity and the phase to be controlled in the transmission-side signal light multiplexed by the multimode multiplexer and, considering also a detection result, sets the control target value.

4. The optical communication device according to claim 1 , further comprising an amplifier that amplifies the multiplexed transmission-side signal light after being multiplexed by the multimode multiplexer.

5. The optical communication device according to claim 1 further comprising an amplifier that amplifies the distributed transmission-side signal light after being distributed by the transmission-side demultiplexer.

6. The optical communication device according to claim 1 comprising a optical multiplexer/demultiplexer that includes a function of both the reception-side multimode demultiplexer and the multimode multiplexer.

7. An optical communication system comprising:
an optical communication device that is disposed on a ground side; and
an optical communication device on a communication partner side that is included in a flying object that flies in midair and communicates with the optical communication device by a signal light, wherein
the optical communication device includes:
a transmission medium of a multimode type that transmits a reception-side signal light incident through a free space;
a reception-side demultiplexer that distributes the reception-side signal light into a plurality of distributed reception-side signal lights at a distribution ratio, the distribution ratio being ratio depending on an intensity distribution of a plurality of mutually different propagation modes included in the reception-side signal light which has passed through the transmission medium;
a transmission-side multimode demultiplexer that distributes a transmission-side signal light to be transmitted into a plurality of distributed transmission-side signal lights;
a signal processing device that includes a detection function and a setting function, the detection function being a function that detects either or both of a light intensity and a phase in each distributed reception-side signal light, the setting function being a function that sets a control target value for either or both of a light intensity and a phase to be controlled in each distributed transmission-side signal light to a value depending on a detection result by the detection function;
a modulator that adjusts either or both of a light intensity and a phase to be controlled in the distributed transmission-side signal light to the control target value set by the signal processing device; and
a multimode multiplexer that multiplexes the plurality of distributed transmission-side signal lights obtained after being adjusted by the modulator.

8. An optical communication method comprising:
receiving a reception-side signal light incident through a free space by using a transmission medium of a multimode type;
multi-mode demultiplexing the reception-side signal light into a plurality of distributed reception-side signal lights at a distribution ratio, the distribution ratio being ratio depending on an intensity distribution of a plurality of mutually different propagation modes included in the reception-side signal light after passing through the transmission medium;
detecting either or both of a light intensity and a phase in each distributed reception-side signal light;
demultiplexing a transmission-side signal light to be transmitted to a plurality of distributed transmission-side signal lights;
setting a control target value for either or both of a light intensity and a phase to be controlled in each distributed transmission-side signal light to a value depending on a result of the detecting;
adjusting either or both of a light intensity and a phase to be controlled in the distributed transmission-side signal light to the control target value after setting; and
multi-mode multiplexing a plurality of distributed transmission-side signal lights obtained after being adjusted and emitting a multiplexed transmission-side signal light.

Assignees

• Nec Corp

Inventors

• Tanaka Akihiro
• Ito Toshiharu
• Hosokawa Kohei
• Takahashi Seigo
• Arikawa Manabu

Classifications

• H04B10/50

  Transmitters · CPC title

• H04B10/112

  Line-of-sight transmission over an extended range · CPC title

• H04B10/40

  Transceivers · CPC title

• H04B10/118 Primary

  specially adapted for satellite communication · CPC title

• H04B10/60

  Receivers · CPC title