Optical transmitter, optical communication system, and optical transmission/reception control method

Patent metadata

Field	Value
Publication number	US-9998230-B2
Application number	US-201715654847-A
Country	US
Kind code	B2
Filing date	Jul 20, 2017
Priority date	Jul 26, 2016
Publication date	Jun 12, 2018
Grant date	Jun 12, 2018

Abstract

An optical transmitter includes an optical modulator to modulate light having a predetermined wavelength into an optical signal based on a data signal, a memory, and a processor coupled to the memory and the processor configured to modulate an input signal into a multi-carrier signal so as to generate the data signal, the multi-carrier signal including a plurality of subcarriers each to which a transmission capacity is allocated, acquire a first frequency distribution of an intensity of the multi-carrier signal, acquire a second frequency distribution of an intensity of the optical signal, control the modulating of the input signal into the multi-carrier signal to change a number of subcarriers of the multi-carrier signal, and control the optical modulator to adjust a modulation characteristic of the optical modulator so that a divergence between the first frequency distribution and the second frequency distribution is equal to or less than a predetermined value.

First claim

What is claimed is:

1. An optical transmitter comprising:
an optical modulator configured to modulate light having a predetermined wavelength into an optical signal based on a data signal;
a memory; and
a processor coupled to the memory and the processor configured to:
modulate an input signal into a multi-carrier signal so as to generate the data signal, the multi-carrier signal including a plurality of subcarriers each to which a transmission capacity is allocated;
acquire a first frequency distribution of an intensity of the multi-carrier signal;
acquire a second frequency distribution of an intensity of the optical signal;
control the modulating of the input signal into the multi-carrier signal to change a number of subcarriers of the multi-carrier signal; and
control the optical modulator to adjust a modulation characteristic of the optical modulator so that a divergence between the first frequency distribution and the second frequency distribution is equal to or less than a predetermined value.

2. The optical transmitter according to claim 1 ,
wherein the processor is configured to adjust the modulation characteristic so that the second frequency distribution becomes a normal distribution.

3. The optical transmitter according to claim 1 ,
wherein the processor is configured to notify an optical receiver receiving the optical signal of the number of subcarriers of the multi-carrier signal.

4. An optical communication system comprising:
an optical transmitter configured to include:
an optical modulator configured to modulate light having a predetermined wavelength into an optical signal based on a data signal;
a first memory; and
a first processor coupled to the first memory and the first processor configured to:
modulate an input signal into a multi-carrier signal so as to generate the data signal, the multi-carrier signal including a plurality of subcarriers each to which a transmission capacity is allocated;
acquire a first frequency distribution of an intensity of the multi-carrier signal;
acquire a second frequency distribution of an intensity of the optical signal;
control the modulating of the input signal into the multi-carrier signal to change a number of subcarriers of the multi-carrier signal;
control the optical modulator to adjust a modulation characteristic of the optical modulator so that a divergence between the first frequency distribution and the second frequency distribution is equal to or less than a predetermined value; and
transmit the number of subcarriers of the multi-carrier signal, and
an optical receiver configured to include:
an optical demodulator configured to demodulate the optical signal received from the optical transmitter;
a second memory; and
a second processor coupled to the second memory and the second processor configured to control the optical demodulator based on the number of subcarriers of the multi-carrier signal.

5. The optical communication system according to claim 4 ,
wherein the first processor is configured to adjust the modulation characteristic so that the second frequency distribution becomes a normal distribution.

6. An optical transmission/reception control method comprising:
modulating an input signal into a multi-carrier signal so as to generate a data signal, the multi-carrier signal including a plurality of subcarriers each to which a transmission capacity is allocated, by a first processor;
modulating light having a predetermined wavelength into an optical signal based on the data signal, by an optical modulator;
acquiring a first frequency distribution of an intensity of the multi-carrier signal, by a first processor;
acquiring a second frequency distribution of an intensity of the optical signal, by a first processor;
controlling the modulating of the input signal into the multi-carrier signal to change a number of subcarriers of the multi-carrier signal, by a first processor;
controlling the optical modulator to adjust a modulation characteristic of the optical modulator so that a divergence between the first frequency distribution and the second frequency distribution is equal to or less than a predetermined value, by a first processor;
transmitting the number of subcarriers of the multi-carrier signal, by a first processor;
demodulating the optical signal, by an optical demodulator; and
controlling the optical demodulator based on the number of subcarriers of the multi-carrier signal, by a second processor.

7. The optical transmission/reception control method according claim 6 ,
wherein the first processor is configured to adjust the modulation characteristic so that the second frequency distribution becomes a normal distribution.

Assignees

• Fujitsu Ltd

Inventors

• Nishihara Masato
• Tanaka Toshiki
• Takahara Tomoo
• Okabe Ryou
• Kai Yutaka

Classifications

• H04L27/2627 Primary

  Modulators · CPC title

• H04B10/5161 Primary

  Combination of different modulation schemes · CPC title

• H04B10/60

  Receivers · CPC title

• H04B10/548

  Phase or frequency modulation · CPC title

• H04B10/588

  in external modulation systems · CPC title