Transmission device, reception device, and transmission method

Patent metadata

Field	Value
Publication number	US-10698228-B2
Application number	US-201916387769-A
Country	US
Kind code	B2
Filing date	Apr 18, 2019
Priority date	Apr 27, 2018
Publication date	Jun 30, 2020
Grant date	Jun 30, 2020

Abstract

A transmission method includes mapping a data signal to a symbol according to a modulation mode to generate a first electric field signal and a second electric field signal, modulating a light beam based on the first electric field signal and the second electric field signal to generate a first polarized light beam and a second polarized light beam that are orthogonal to each other, multiplexing the first polarized light beam and the second polarized light beam, applying transformation processing of changing each polarization angle of the first polarized light beam and the second polarized light beam to the first electric field signal and the second electric field signal and adding polarization information indicating a change amount caused by the transformation processing for each polarization angle of the first polarized light beam and the second polarized light beam to the first electric field signal and the second electric field signal.

First claim

What is claimed is:

1. A transmission device comprising:
a transmission processing circuit configured to map a data signal to a symbol according to a modulation mode to generate a first electric field signal and a second electric field signal;
a modulator configured to optically modulate a light beam based on the first electric field signal and the second electric field signal to generate a first polarized light beam and a second polarized light beam that are orthogonal to each other; and
a multiplexer configured to multiplex the first polarized light beam and the second polarized light beam, wherein
the transmission processing circuit applies unitary transformation regarding the first polarized light beam and the second polarized light beam, or unitary transformation between symbols at different timings, to the first electric field signal and the second electric field signal, inserts a first reference signal having a predetermined pattern used in demodulation processing of the first electric field signal in the first electric field signal subjected to the unitary transformation, and inserts a second reference signal having a predetermined pattern used in demodulation processing of the second electric field signal in the second electric field signal subjected to the unitary transformation.

2. The transmission device according to claim 1 , wherein the transmission processing circuit applies transformation processing of changing each polarization angle of the first polarized light beam and the second polarized light beam to the first electric field signal and the second electric field signal.

3. The transmission device according to claim 2 , wherein the transmission processing circuit intermittently execute the transformation processing.

4. The transmission device according to claim 3 , wherein the transmission processing circuit executes transformation processing of continuously changing each polarization angle of the first polarized light beam and the second polarized light beam from a predetermined angle to a plurality of angles.

5. The transmission device according to claim 1 , further comprising:
a front end circuit configured to receive a polarized multiplexed light beam of the first polarized light beam and the second polarized light beam, divide the polarized multiplexed light beam into the first polarized light beam and the second polarized light beam, and transform the first polarized light beam and the second polarized light beam into the first electric field signal and the second electric field signal, respectively; and
a reception processing circuit configured to demodulate the first electric field signal based on the first reference signal, and demodulate the second electric field signal based on the second reference signal, wherein
the reception processing circuit applies transformation processing that is inverse to the unitary transformation to the first electric field signal and the second electric field signal.

6. The transmission device according to claim 5 , wherein
the reception processing circuit
executes error correction processing of the data signal by soft decision based on an error correction code added to the data signal,
calculates a parameter used in the soft decision regarding the first electric field signal that is not subjected to the unitary transformation based on power level of the first reference signal,
calculates a parameter used in the soft decision regarding the first electric field signal that is subjected to the unitary transformation based on power level of the first reference signal,
calculates a parameter used in the soft decision regarding the second electric field signal that is not subjected to the unitary transformation based on power level of the second reference signal, and
calculates a parameter used in the soft decision regarding the second electric field signal that is subjected to the unitary transformation based on power level of the second reference signal.

7. A transmission device comprising:
a transmission processing circuit configured to map a data signal to a symbol according to a modulation mode to generate a first electric field signal and a second electric field signal;
a modulator configured to optically modulate a light beam based on the first electric field signal and the second electric field signal to generate a first polarized light beam and a second polarized light beam that are orthogonal to each other; and
a multiplexer configured to multiplex the first polarized light beam and the second polarized light beam, wherein
the transmission processing circuit
applies transformation processing of changing each polarization angle of the first polarized light beam and the second polarized light beam to the first electric field signal and the second electric field signal, and
adds polarization information indicating a change amount caused by the transformation processing for each polarization angle of the first polarized light beam and the second polarized light beam to the first electric field signal and the second electric field signal.

8. The transmission device according to claim 7 , further comprising:
a front end circuit configured to receive a polarized multiplexed light beam of the first polarized light beam and the second polarized light beam, divide the polarized multiplexed light beam into the first polarized light beam and the second polarized light beam, and transform the first polarized light beam and the second polarized light beam into the first electric field signal and the second electric field signal, respectively; and
a reception processing circuit configured to demodulate the first electric field signal and the second electric field signal based on the polarization information, wherein
the reception processing circuit applies transformation processing that is inverse to the transformation processing to the first electric field signal and the second electric field signal.

9. A transmission method comprising:
mapping a data signal to a symbol according to a modulation mode to generate a first electric field signal and a second electric field signal;
optically modulating a light beam based on the first electric field signal and the second electric field signal to generate a first polarized light beam and a second polarized light beam that are orthogonal to each other;
multiplexing the first polarized light beam and the second polarized light beam;
applying unitary transformation regarding the first polarized light beam and the second polarized light beam, or unitary transformation between the symbols at different timings to the first electric field signal and the second electric field signal;
inserting a first reference signal having a predetermined pattern used in demodulation processing of the first electric field signal in the first electric field signal that is subjected to the unitary transformation; and
inserting a second reference signal having a predetermined pattern used in demodulation processing of the second electric field signal in the second electric field signal that is subjected to the unitary transformation.

10. The transmission method according to claim 9 , wherein the unitary transformation is transformation processing applied to the first electric field signal and the second electric field signal to change each polarization angle of the first polarized light beam and the second polarized light beam.

11. The transmission method according to claim 10 , wherein the transformation processing is intermittently executed.

12. The transmission method according to claim 11 , wherein the transformation processing is transformation processing of continuously chan

Assignees

• Fujitsu Ltd

Inventors

• Oyama Tomofumi
• Nakashima Hisao

Classifications

• H04J14/06 Primary

  Polarisation multiplex systems · CPC title

• G02B27/286 Primary

  for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another (G02B5/3083 takes precedence; light guide coupling means utilising polarising elements G02B6/34) · CPC title

• G02B27/281

  used for attenuating light intensity, e.g. comprising rotatable polarising elements · CPC title

• H04L1/20

  using signal quality detector · CPC title

• G02B27/283

  used for beam splitting or combining · CPC title