Multi-carrier optical transmission system, optical transmitter, and optical receiver

Patent metadata

Field	Value
Publication number	US-2016285548-A1
Application number	US-201615179075-A
Country	US
Kind code	A1
Filing date	Jun 10, 2016
Priority date	Dec 13, 2013
Publication date	Sep 29, 2016
Grant date	—

Abstract

An optical transmitter transmits to an optical receiver a multi-carrier modulated signal light by driving a light source with a modulated signal modulated with a multi-carrier modulation scheme. The optical receiver monitors reception characteristic of any of subcarrier signals included in the modulated signal and transmits a monitor result to the optical transmitter. The optical transmitter controls drive conditions of the light source based on the monitor result received from the optical receiver.

First claim

What is claimed is:

1 . A multi-carrier optical transmission system comprising:
an optical transmitter configured to include a light source and to transmit a multi-carrier modulated signal light by driving the light source with a modulated signal modulated by using a multi-carrier modulation scheme; and an optical receiver configured to receive the multi-carrier modulated signal light transmitted by the optical transmitter to demodulate the modulated signal, wherein the optical receiver includes: a monitor configured to monitor a reception characteristic of any of subcarrier signals included in the modulated signal; and a transmission unit configured to transmit a monitor result by the monitor to the optical transmitter, and wherein the optical transmitter includes: a controller configured to control a drive condition of the light source based on the monitor result received from the optical receiver.

2 . The multi-carrier optical transmission system according to claim 1 , wherein the subcarrier signal to be monitored by the monitor has a frequency at which a change of the drive condition of the light source impacts on a transmission characteristic of the multi-carrier modulated signal light more than any other frequency.

3 . The multi-carrier optical transmission system according to claim 2 , wherein the frequency to be monitored by the monitor corresponds to a frequency at which variations of a relative intensity noise caused by a change of a drive current of the light source are greater than those at any other frequency.

4 . The multi-carrier optical transmission system according to claim 3 , wherein the frequency to be monitored by the monitor corresponds to a relaxation oscillation frequency of the light source.

5 . The multi-carrier optical transmission system according to claim 2 , wherein the frequency corresponds to a frequency at which variations of a frequency response caused by the change of a drive current of the light source are greater than those at any other frequency.

6 . The multi-carrier optical transmission system according to claim 1 , wherein the controller of the optical transmitter
stores a correspondence between the monitor result and the drive condition in advance, and determines the drive condition based on the monitor result and the correspondence.

7 . The multi-carrier optical transmission system according to claim 1 , wherein the multi-carrier modulation scheme is a discrete multi-tone modulation scheme.

8 . The multi-carrier optical transmission system according to claim 1 , wherein the reception characteristic is a bit error rate or a signal to noise ratio.

9 . An optical transmitter comprising:
a multi-carrier modulator configured to generate a modulated signal modulated by using a multi-carrier modulation scheme; a light source driven with the modulated signal to transmit a multi-carrier modulated signal light; and a controller configured to control a drive condition of the light source based on a monitored reception characteristic of any of subcarrier signals included in the modulated signal, the monitored reception characteristic being monitored by an optical receiver which received the multi-carrier modulated signal light.

10 . The optical transmitter according to claim 9 , wherein the controller
stores a correspondence between the monitor result and the drive condition, and determines the drive condition based on the monitor result and the correspondence.

11 . An optical receiver to receive and demodulate a multi-carrier modulated signal light, the optical receiver comprising:
a monitor configured to monitor a reception characteristic of any of subcarrier signals included in a modulated signal, the multi-carrier modulated signal light being transmitted by an optical transmitter configured to include a light source and to transmit the multi-carrier modulated signal light by driving the light source with the modulated signal modulated by using a multi-carrier modulation scheme; and a transmission unit configured to transmit a monitor result obtained by the monitor to the optical transmitter as control information to control a drive condition of the light source.

12 . The optical receiver according to claim 11 , wherein the subcarrier signal to be monitored by the monitor has a frequency at which a change of the drive condition of the light source impacts on a transmission characteristic of the multi-carrier modulated signal light more than any other frequency.

13 . The optical receiver according to claim 12 , wherein the frequency corresponds to a frequency at which variations of a relative intensity noise caused by a change of a drive current of the light source are greater than those at any other frequency.

14 . The optical receiver according to claim 13 , wherein the frequency to be monitored by the monitor corresponds to a relaxation oscillation frequency of the light source.

15 . The optical receiver according to claim 12 , wherein the frequency to be monitored by the monitor corresponds to a frequency at which variations of a frequency response caused by the change of a drive current of the light source are greater than those at any other frequency.

16 . The optical receiver according to claim 11 , wherein the multi-carrier modulation scheme is a discrete multi-tone modulation scheme.

17 . The optical receiver according to claim 11 , wherein the reception characteristic is a bit error rate or a signal to noise ratio.

Assignees

• Fujitsu Ltd

Inventors

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

Classifications

• H04B10/564

  Power control · CPC title

• H04B10/0795

  Performance monitoring; Measurement of transmission parameters · CPC title

• H04B10/40

  Transceivers · CPC title

• H04B10/0779

  Monitoring line transmitter or line receiver equipment · CPC title

• H04B10/0799

  Monitoring line transmitter or line receiver equipment · CPC title