Control device, compensation device, program, and control method

Patent metadata

Field	Value
Publication number	US-12375178-B2
Application number	US-202418893993-A
Country	US
Kind code	B2
Filing date	Sep 24, 2024
Priority date	Jun 22, 2023
Publication date	Jul 29, 2025
Grant date	Jul 29, 2025

Abstract

A control device which controls an operation of a compensation device which compensates for birefringence and/or polarization mode dispersion, which is received by signal light having propagated through an optical transmission line, by digital signal processing using a finite impulse response filter includes: a detection signal reception unit which receives a detection signal which is a signal indicating a detection result of a detection device which optically detects polarization fluctuation in the optical transmission line; and a setting unit which decides a setting regarding an update frequency or an update interval of the number of taps of the finite impulse response filter or an update frequency or an update interval of a tap coefficient of the finite impulse response filter, based on the detection result of the detection device.

First claim

What is claimed is:

1. A control device which controls an operation of a compensation device which compensates for birefringence and/or polarization mode dispersion, which is received by signal light having propagated through an optical transmission line, by digital signal processing using a finite impulse response filter, wherein:
the control device receives a detection signal which is a signal indicating a detection result of a detection device which optically detects polarization fluctuation in the optical transmission line; and
the control device sets a setting regarding an update frequency or an update interval of the number of taps of the finite impulse response filter or an update frequency or an update interval of a tap coefficient of the finite impulse response filter, based on the detection result of the detection device.

2. The control device according to claim 1 , wherein
the control device
determines whether an absolute value of a fluctuation amount of the polarization fluctuation is larger than a predetermined threshold value, based on the detection result of the detection device, and
when it is determined that the absolute value of the fluctuation amount of the polarization fluctuation is larger than the threshold value, sets (i) a set value of the update frequency of the number of taps and/or the tap coefficient to be larger than a current set value, (ii) the set value of the update frequency of the number of taps and/or the tap coefficient to be a predetermined first value, (iii) a set value of the update interval of the number of taps and/or the tap coefficient to be smaller than a current set value, or (iv) to set the set value of the update interval of the number of taps and/or the tap coefficient to be a predetermined second value.

3. The control device according to claim 1 , wherein
the control device
determines whether an absolute value of a fluctuation amount of the polarization fluctuation is larger than a predetermined threshold value, based on the detection result of the detection device, and
when it is not determined that the absolute value of the fluctuation amount of the polarization fluctuation is larger than the threshold value, sets (i) a set value of the update frequency of the number of taps and/or the tap coefficient to be smaller than a current set value, (ii) the set value of the update frequency of the number of taps and/or the tap coefficient to be a predetermined third value, (iii) a set value of the update interval of the number of taps and/or the tap coefficient to be larger than a current set value, or (iv) the set value of the update interval of the number of taps and/or the tap coefficient to be a predetermined fourth value.

4. The control device according to claim 1 , wherein
the control device updates the number of taps or the tap coefficient at the update frequency or the update interval determined by the setting set by the control device.

5. The control device according to claim 1 , wherein
the compensation device compensates for birefringence and/or polarization mode dispersion received by first signal light having propagated through the optical transmission line,
the detection device optically detects polarization fluctuation of second signal light having propagated through the optical transmission line, and
the first signal light and the second signal light have different wavelengths.

6. The control device according to claim 5 , wherein
the detection device includes an optical delay interferometer, a polarimeter, a state-of-polarization measuring instrument, or a Stokes parameter measuring instrument for optically detecting the polarization fluctuation of the second signal light.

7. The control device according to claim 1 , wherein
the control device controls operations of a plurality of compensation devices including the compensation device which compensates for birefringence and/or polarization mode dispersion, which is received by each of a plurality of beams of signal light having propagated through the optical transmission line, by digital signal processing using a finite impulse response filter,
the control device sets the setting regarding a plurality of finite impulse response filters, which includes the finite impulse response filter, arranged in the plurality of compensation devices, based on the detection result of the detection device, and
the plurality of beams of signal light have different wavelengths.

8. The control device according to claim 2 , wherein
the control device
determines whether an absolute value of a fluctuation amount of the polarization fluctuation is larger than a predetermined threshold value, based on the detection result of the detection device, and
when it is not determined that the absolute value of the fluctuation amount of the polarization fluctuation is larger than the threshold value, sets (i) a set value of the update frequency of the number of taps and/or the tap coefficient to be smaller than a current set value, (ii) the set value of the update frequency of the number of taps and/or the tap coefficient to be a predetermined third value, (iii) a set value of the update interval of the number of taps and/or the tap coefficient to be larger than a current set value, or (iv) the set value of the update interval of the number of taps and/or the tap coefficient to be a predetermined fourth value.

9. The control device according to claim 2 , wherein
the control device updates the number of taps or the tap coefficient at the update frequency or the update interval determined by the setting decided by the control device.

10. The control device according to claim 3 , wherein
the control device updates the number of taps or the tap coefficient at the update frequency or the update interval determined by the setting decided by the control device.

11. The control device according to claim 2 , wherein
the compensation device compensates for birefringence and/or polarization mode dispersion received by first signal light having propagated through the optical transmission line,
the detection device optically detects polarization fluctuation of second signal light having propagated through the optical transmission line, and
the first signal light and the second signal light have different wavelengths.

12. The control device according to claim 3 , wherein
the compensation device compensates for birefringence and/or polarization mode dispersion received by first signal light having propagated through the optical transmission line,
the detection device optically detects polarization fluctuation of second signal light having propagated through the optical transmission line, and
the first signal light and the second signal light have different wavelengths.

13. The control device according to claim 4 , wherein
the compensation device compensates for birefringence and/or polarization mode dispersion received by first signal light having propagated through the optical transmission line,
the detection device optically detects polarization fluctuation of second signal light having propagated through the optical transmission line, and
the first signal light and the second signal light have different wavelengths.

14. The control device according to claim 5 , wherein
the detection device includes an optical delay interferometer for optically detecting the polarization fluctuation of the second signal light.

15. The control device according to claim 2 , wherein
the control device controls operations of a plurality of compensation devices including the compensation device which compensates for birefringenc

Assignees

• Univ Meiji
• Softbank Corp

Inventors

• Ryu Shiro

Classifications

• H04B10/07951 Primary

  Monitoring or measuring chromatic dispersion or PMD · CPC title

• H04B10/2572

  due to forms of polarisation-dependent distortion other than PMD · CPC title

• H04B10/2569 Primary

  due to polarisation mode dispersion [PMD] · CPC title