Wavelength division multiplexed telecommunication system with automatic compensation of chromatic dispersion

Patent metadata

Field	Value
Publication number	US-2017187482-A1
Application number	US-201514757689-A
Country	US
Kind code	A1
Filing date	Dec 23, 2015
Priority date	Dec 23, 2015
Publication date	Jun 29, 2017
Grant date	—

Abstract

A wavelength division multiplexed telecommunication system with automatic compensation of chromatic dispersion in a predetermined wavelength band, said WDM telecommunication system comprising a probe signal detection unit at a receiver side adapted to detect amplitude modulated probe signals generated by a probe signal generation unit at a transmitter side with a predetermined relative phase difference and transmitted through an optical link to said receiver side; and a chromatic dispersion compensation unit adapted to compensate the chromatic dispersion in response to a relative phase difference of the amplitude modulated probe signals detected by said probe signal detection unit at the receiver side.

First claim

1 . A wavelength division multiplexed telecommunication system with automatic compensation of chromatic dispersion in a predetermined wavelength band, said WDM telecommunication system comprising:
a probe signal detection unit at a receiver side adapted to detect amplitude modulated probe signals generated by a probe signal generation unit at a transmitter side with a predetermined relative phase difference and transmitted through an optical link to said receiver side; and a chromatic dispersion compensation unit adapted to compensate the chromatic dispersion in response to a relative phase difference of the amplitude modulated probe signals detected by said probe signal detection unit at the receiver side.

2 . The WDM telecommunication system according to claim 1 , wherein said chromatic dispersion compensation unit comprises a tunable dispersion compensation module (TDCM) which is tuned until the relative phase difference between the detected amplitude modulated probe signals is minimized.

3 . The WDM telecommunication system according to claim 1 , wherein said probe signal generation unit is adapted to generate probe signals with the same modulation frequency and with the predetermined relative phase difference.

4 . The WDM telecommunication system according to claim 3 , wherein the amplitude modulated probe signals generated by said probe signal generation unit at the transmitter side comprise probe signal wavelengths surrounding the center of the predetermined wavelength band.

5 . The WDM telecommunication system according to claim 2 , wherein the tunable dispersion compensation module (TDCM) of said chromatic dispersion compensation unit is adapted to vary its chromatic dispersion setting until the amplitude modulated probe signals detected by said probe signal detection unit are in phase.

6 . The WDM telecommunication system according to claim 1 , wherein the amplitude modulated probe signals generated by said probe signal generation unit are injected by means of a passive coupler, a filter or a switch to a line transporting wavelength division multiplexed, WDM, signals output by a WDM multiplexer and amplified by a booster amplifier at the transmitter side.

7 . The WDM telecommunication system according to claim 6 , wherein the booster amplifier at the transmitter side is connected via said optical link to a preamplifier at the receiver side adapted to amplify the received WDM signals and adapted to amplify the amplitude modulated probe signals.

8 . The WDM telecommunication system according to claim 7 , wherein the preamplifier at the receiver side is connected to a WDM demultiplexer adapted to demultiplex the received WDM signals.

9 . The WDM telecommunication system according to claim 8 , wherein the transmitted amplitude modulated probe signals are extracted at the receiver side by means of a splitter, filter or a switch at the output of the preamplifier or from one of the outputs of the WDM demultiplexer and supplied to said probe signal detection unit.

10 . The WDM telecommunication system according to claim 1 , wherein said probe signal detection unit comprises a phase comparator adapted to derive a relative phase difference between phases of extracted amplitude modulated probe signals and to communicate the derived relative phase difference to said chromatic dispersion compensation unit.

11 . The WDM telecommunication system according to claim 10 , wherein said probe signal detection unit comprises photo detectors adapted to detect extracted amplitude modulated probe signals and to generate corresponding electrical signals supplied to the phase comparator of said probe signal detection unit.

12 . The WDM telecommunication system according to claim 1 , wherein said probe signal detection unit comprises a balanced photo detector having an output voltage corresponding to the phase difference between the phases of amplitude modulated probe signals extracted at the receiver side.

13 . The WDM telecommunication system according to claim 12 , wherein a tunable dispersion compensation module (TDCM) of the chromatic dispersion compensation unit is tuned until the output voltage of the balanced photo detector becomes minimal.

14 . The WDM telecommunication system according to claim 3 , wherein the wavelength of at least one amplitude modulated probe signal generated by said probe signal generation unit is tunable.

15 . The WDM telecommunication system according to claim 3 , wherein the modulation frequency of the amplitude modulated probe signals generated by laser diodes of said probe signal generation unit is switchable to increase an accuracy of the chromatic dispersion compensation.

16 . The WDM telecommunication system according to claim 3 , wherein a frequency spacing between probe signal wavelengths of the amplitude modulated probe signals generated by laser diodes of said probe signal generation unit is varied to increase an accuracy of the chromatic dispersion compensation.

17 . The WDM telecommunication system according to claim 1 , wherein an optical supervisory channel (OSC) is provided for communication between a first control unit adapted to control the probe signal generation unit at the transmitter side and a second control unit adapted to control the probe signal detection unit, and/or the chromatic dispersion compensation unit.

18 . The WDM telecommunication system according to claim 1 , wherein said optical link is a bidirectional optical transmission link comprising at least one optical fiber.

19 . The WDM telecommunication system according to claim 1 , wherein said system is a dense wavelength division multiplexed system (DWDM).

20 . The WDM telecommunication system according to claim 1 , wherein said predetermined wavelength band comprises a C-band, an L-band or an S-band.

21 . The WDM telecommunication system according to claim 1 , wherein the WDM telecommunication switch comprises a 100 Gb/sec direct detect WDM system using multilevel modulation formats comprising PAM4, PAM8 or DMT.

22 . A method for compensating a chromatic dispersion in a predetermined wavelength band, the method comprising the steps of:
(a) generating amplitude modulated probe signals with a predetermined relative phase difference at a transmitter side and transmitting the generated amplitude modulated probe signals through an optical link to a receiver side; (b) detecting at the receiver side a relative phase difference of the received amplitude modulated probe signals; and (c) compensating automatically the chromatic dispersion in response to the detected relative phase difference of the received amplitude modulated probe signals.

23 . The method according to claim 22 , wherein the amplitude modulated probe signals are generated by laser diodes with the same modulation frequency and comprise the predetermined relative phase difference.

24 . The method according to claim 22 , wherein the received amplitude modulated probe signals are extracted at the receiver side and the relative phase difference between the phases of the extracted amplitude modulated probe signals is detected.

25 . The method according to claim 24 , wherein a chromatic dispersion setting of a tunable dispersion compensation module (TDCM) is varied until the relative phase difference between the phases of the extracted amplitude modulated probe signals is minimal.

26 . The method according to claim 22 , wh

Assignees

• Adva Optical Networking Se

Inventors

• Alfiad Mohammad
• Cornelius Fuerst
• Tibuleac Sorin
• Meyer Christophe

Classifications

• H04B10/6161

  Compensation of chromatic dispersion · CPC title

• H04B10/6971

  using equalisation · CPC title

• H04L5/0048

  Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091) · CPC title

• H04B10/541 Primary

  Digital intensity or amplitude modulation · CPC title

• H04J14/02 Primary

  Wavelength-division multiplex systems · CPC title