Method and tuning device for tuning a tunable optical transmitter to a predetermined target wavelength

Patent metadata

Field	Value
Publication number	US-9473246-B2
Application number	US-201514704046-A
Country	US
Kind code	B2
Filing date	May 5, 2015
Priority date	May 5, 2014
Publication date	Oct 18, 2016
Grant date	Oct 18, 2016

Abstract

A method for tuning a tunable optical transmitter to a target wavelength includes applying at least one tuning signal to the tunable optical transmitter to control the tunable optical transmitter to create an optical calibration signal according to nominal tuning information for the tunable optical transmitter. The optical calibration signal has a wavelength lying within a secure wavelength range, and the nominal tuning information is based on a nominal wavelength dependency for the tunable optical transmitter. The method also includes measuring a deviation between an actual wavelength dependency of the tunable optical transmitter and the nominal wavelength dependency, and determining calibration information based on that deviation. The calibration information is applied to determine a corrected nominal wavelength dependency from which target tuning information is determined. The tunable optical transmitter is controlled to create an optical channel signal according to the target tuning information.

First claim

The invention claimed is:

1. A method for tuning a tunable optical transmitter to a target wavelength, the tunable optical transmitter being included in a plurality of optical transmitters connected to a first end of an optical WDM transmission link, the method comprising:
(a) supplying at least one tuning signal to the tunable optical transmitter to control the tunable optical transmitter to create an optical calibration signal according to nominal tuning information comprising at least one parameter of the at least one tuning signal, wherein
(i) the optical calibration signal has a wavelength lying within a secure wavelength range which excludes any optical channel wavelength range predefined for transmitting an optical channel signal by another one of the plurality of optical transmitters in the direction of the optical calibration signal over the WDM transmission link, and
(ii) the nominal tuning information is determined from a known nominal wavelength dependency characterizing the wavelength dependency of the tunable optical transmitter on the at least one parameter of the at least one tuning signal;

(b) determining calibration information by directly or indirectly measuring, within the secure wavelength range, a deviation between an actual wavelength dependency of the tunable optical transmitter and the nominal wavelength dependency; and
(c) controlling the tunable optical transmitter to create an optical channel signal according to target tuning information which is determined from a corrected nominal wavelength dependency corrected with respect to the nominal wavelength dependency based on the calibration information, the optical channel signal having a wavelength within a predetermined acceptable tolerance to the target wavelength.

2. The method of claim 1 wherein the calibration information is determined by directly or indirectly measuring a deviation between the actual wavelength of the optical calibration signal and a respective nominal wavelength which should have been achieved according to the nominal wavelength dependency.

3. The method of claim 2 wherein the calibration information is determined for at least two points of the nominal wavelength dependency, wherein the optical tunable transmitter is controlled, in succeeding steps, to create the optical calibration signal according to tuning information comprising a respective number of different values for the at least one parameter of the at least one tuning signal.

4. The method of claim 1 wherein the calibration information is determined by:
(a) varying at least one parameter of the tuning signal applied to control the tunable optical transmitter until the optical calibration signal reaches a predetermined wavelength; and
(b) determining the deviation between the actual value of the at least parameter at which the predetermined wavelength has been reached and a respective nominal value of the at least parameter at which the predetermined wavelength should have been reached according to the nominal wavelength dependency.

5. The method of claim 1 wherein the calibration information is determined using a detection unit provided at a second end of the optical WDM transmission link, and further including transmitting the measuring results or information including processed measuring results from the second end of the optical WDM transmission link to the first end of the optical WDM transmission link.

6. The method of claim 1 further including performing a fine tuning process after having controlled the tunable optical transmitter to create the optical channel signal, the fine tuning process comprising continuously or in predetermined time intervals or as a response to predetermined trigger events, maximizing the optical power of the optical channel signal created by the tunable optical transmitter by varying the tuning information supplied to the tunable optical transmitter.

7. A tuning control device for a respective tunable optical transmitter in an optical WDM system where the WDM system includes a plurality of optical transmitters connected to a first end of an optical WDM transmission link, the tuning control device including:
(a) a tuning information generating unit configured to
(i) supply at least one first tuning signal to the respective tunable optical transmitter to control the respective tunable optical transmitter to create at least one optical calibration signal according to nominal tuning information comprising at least one parameter of the at least one first tuning signal, and
(ii) supply at least one second tuning signal to the respective tunable optical transmitter to control the respective tunable optical transmitter to create an optical channel signal according to target tuning information, the optical channel signal having a wavelength within a predetermined acceptable tolerance to a target wavelength for the respective tunable optical transmitter;

(b) a detection unit configured to identify the wavelength of the at least one optical calibration signal;
(c) wherein the optical calibration signal has a wavelength lying within a secure wavelength range which excludes any optical channel wavelength range predefined for transmitting an optical channel signal by another one of the plurality of optical transmitters in the direction of the optical calibration signal over the WDM transmission link, and the nominal tuning information is determined from a known nominal wavelength dependency characterizing the wavelength dependency of the respective tunable optical transmitter on the at least one parameter of the at least one first tuning signal; and
(d) wherein the target tuning information is determined from calibration information which is obtained based on the wavelength of the at least one optical calibration signal identified by the detection unit.

8. The tuning control device of claim 7 wherein the calibration information is determined by directly or indirectly measuring a deviation between the actual wavelength of the optical calibration signal and a respective nominal wavelength which should have been achieved according to the nominal wavelength dependency.

9. The tuning control device of claim 8 wherein the calibration information is determined for at least two points of the nominal wavelength dependency, wherein the respective tunable optical transmitter is controlled, in succeeding steps, to create the optical calibration signal according to nominal tuning information comprising a respective number of different values for the at least one parameter of the at least one tuning signal.

10. The tuning control device of claim 7 wherein the calibration information is determined by:
(a) varying at least one parameter of the first tuning signal applied to control the respective tunable optical transmitter until the calibration signal reaches a predetermined wavelength; and
(b) determining the deviation between the actual value of the at least parameter at which the predetermined wavelength has been reached and a respective nominal value of the at least parameter at which the predetermined wavelength should have been reached according to the nominal wavelength dependency.

11. The tuning control device of claim 7 wherein the calibration information is determined using the detection unit provided at a second end of the optical WDM transmission link.

12. The tuning control device of claim 7 wherein the tuning information generating unit is configured to perform a fine tuning process after having controlled the respective tunable optical transmitter to create the optical channel signal, the fine tuning process comprising continuously or in predetermined time intervals or as a response to pr

Assignees

• Adva Optical Networking Se

Inventors

• Grobe Klaus
• Eiselt Michael

Classifications

• H04B10/506 Primary

  Multiwavelength transmitters · CPC title

• H04B10/572

  Wavelength control · CPC title

• H04B17/11

  for calibration · CPC title

• H04J14/02

  Wavelength-division multiplex systems · CPC title

• H04J14/0307

  Multiplexers; Demultiplexers · CPC title