Optical receiver and superimposed signal detecting method

Patent metadata

Field	Value
Publication number	US-2016337070-A1
Application number	US-201615095698-A
Country	US
Kind code	A1
Filing date	Apr 11, 2016
Priority date	May 14, 2015
Publication date	Nov 17, 2016
Grant date	—

Abstract

An optical receiver includes: a tunable filter configured to partially transmit a wavelength-multiplexed optical-signal including a first optical-signal having a first wavelength, a second optical-signal having a second wavelength, and a third optical-signal having a third wavelength, with a frequency-modulated signal superimposed on each of the first to third optical-signals; a photo detector configured to detect an optical-power of the wavelength-multiplexed optical-signal transmitted through the tunable filter; and a superimposed signal detector configured to detect the frequency-modulated signal superimposed on the first optical-signal, based on an amplitude-modulated signal according to a variation in the optical-power on a first filter setting where both of the first optical-signal and the second optical-signal transmit through the tunable filter, and an amplitude-modulated signal according to a variation in the optical-power on a second filter setting where both of the first optical-signal and the third optical-signal transmit through the tunable filter.

First claim

What is claimed is:

1 . An optical receiver comprising:
a tunable filter configured to partially transmit a wavelength-multiplexed optical signal including a first optical signal having a first wavelength, a second optical signal having a second wavelength adjacent to a short wavelength side of the first wavelength, and a third optical signal having a third wavelength adjacent to a long wavelength side of the first wavelength, with a frequency-modulated signal superimposed on each of the first to third optical signals; a photo detector configured to detect an optical power of the wavelength-multiplexed optical signal transmitted through the tunable filter; and a superimposed signal detector configured to detect the frequency-modulated signal superimposed on the first optical signal, based on an amplitude-modulated signal according to a variation in the optical power detected in the photo detector on a first filter setting where both of the first optical signal and the second optical signal transmit through the tunable filter, and an amplitude-modulated signal according to a variation in the optical power detected in the photo detector on a second filter setting where both of the first optical signal and the third optical signal transmit through the tunable filter.

2 . The optical receiver according to claim 1 ,
wherein the frequency-modulated signal superimposed on each of the first to third optical signals is orthogonally-coded by an orthogonal code, and wherein the superimposed signal detector identifies an amplitude-modulated signal corresponding to the frequency-modulated signal superimposed on the first optical signal based on the orthogonal code.

3 . The optical receiver according to claim 1 ,
wherein, on the first filter setting, a transmission center wavelength of the tunable filter is set to a wavelength between the first wavelength and the second wavelength, and wherein, on the second filter setting, the transmission center wavelength of the tunable filter is set to a wavelength between the first wavelength and the third wavelength.

4 . The optical receiver according to claim 3 , further comprising:
a filtering controller configured to control the first filter setting and the second filter setting, wherein the filtering controller sweeps the transmission center wavelength on each of the first filter setting and the second filter setting.

5 . The optical receiver according to claim 1 ,
wherein the frequency-modulated signals superimposed on each of the first to third optical signals are differentially-coded, and wherein the superimposed signal detector detects the frequency-modulated signal superimposed on the first optical signal by differentially-decoding the amplitude-modulated signal detected on each of the first filter setting and the second filter setting.

6 . A superimposed signal detecting method comprising:
transmitting, to a tunable filter, partially a wavelength-multiplexed optical signal including a first optical signal having a first wavelength, a second optical signal having a second wavelength adjacent to a short wavelength side of the first wavelength, and a third optical signal having a third wavelength adjacent to a long wavelength side of the first wavelength, with a frequency-modulated signal superimposed on each of the first to third optical signals; detecting a first optical power of the wavelength-multiplexed optical signal transmitted through the tunable filter on a first filter setting where both of the first optical signal and the second optical signal transmit through the tunable filter; detecting a second optical power of the wavelength-multiplexed optical signal transmitted through the tunable filter on a second filter setting where both of the first optical signal and the third optical signal transmit through the tunable filter; and detecting a frequency-modulated signal superimposed on the first optical signal, based on an amplitude-modulated signal according to a variation in the first optical power detected on the first filter setting, and an amplitude-modulated signal according to a variation in the second optical power detected on the second filter setting.

Assignees

• Fujitsu Ltd

Inventors

• Nakagawa Goji
• Yamauchi Tomohiro
• Huang Guoxiu
• Yoshida Setsuo
• Oda Shoichiro
• Sone Kyosuke
• Aoki Yasuhiko

Classifications

• H04J14/0221 Primary

  Power control, e.g. to keep the total optical power constant · CPC title

• H04B10/5161

  Combination of different modulation schemes · CPC title

• H04B10/66

  Non-coherent receivers, e.g. using direct detection · CPC title

• H04B10/077 Primary

  using a supervisory or additional signal · CPC title

• H04B10/25

  Arrangements specific to fibre transmission · CPC title