Wavelength cross connect device, branch ratio variable method, and program

Patent metadata

Field	Value
Publication number	US-11677489-B2
Application number	US-202017437116-A
Country	US
Kind code	B2
Filing date	Mar 9, 2020
Priority date	Mar 20, 2019
Publication date	Jun 13, 2023
Grant date	Jun 13, 2023

Abstract

A large number of degrees for relays of optical signals transmitted via optical paths in the degrees is secured. A wavelength cross-connect device 20A performs a relay by splitting optical signals from respective degrees indicated by reference numerals 40l, 40h, 40m, 40q, each of the degrees being provided by optical fibers, via respective optical couplers and outputting the split optical signals to output sides of the plurality of degrees via respective WSSs 23a to 23d. As the optical couplers, variable couplers 27a to 27d whose respective splitting ratios, each of which is a ratio of optical signal power losses in splitting an optical signal, are variable are used. The wavelength cross-connect device 20A includes a control unit 26 that performs control to change the splitting ratios in such a manner as to eliminate an imbalance among OSNR margins of the output sides of the degrees in which a plurality of optical paths transmitting the split optical signals extend. The control unit 26 calculates the margins for the respective optical paths transmitting the split optical signals via the variable couplers 27a to 27d, for each of the output sides of the degrees. The control unit 26 performs control to, based on respective smallest margins of the degrees in all the margins, change the splitting ratios of the variable couplers 27a to 27d in such a manner as to eliminate an imbalance between the margins of the degrees.

First claim

The invention claimed is:

1. A wavelength cross-connect device for performing a relay by splitting optical signals transmitted from input sides of a plurality of degrees each provided by optical fibers, via respective optical couplers and outputting the split optical signals to output sides of the plurality of degrees via respective WSSs (wavelength selective switches), wherein:
as each of the optical couplers, a variable splitting-ratio coupler whose splitting ratio that is a ratio of optical signal power losses in splitting an optical signal is variable is used;
the wavelength cross-connect device includes a control unit that includes one or more processors and configured to perform control to change the splitting ratios of the variable splitting-ratio couplers in such a manner as to eliminate an imbalance between optical signal-to-noise ratio margins of the output sides of the degrees in which a plurality of optical paths transmitting the respective optical signals subsequent to the splitting extend; and
the control unit is configured to calculate the margins for the respective optical paths on the output side, for each of the degrees, and perform control to, based on respective smallest margins of the degrees, the smallest margins being obtained from all the calculated margins, change the splitting ratios of the variable splitting-ratio couplers in such a manner as to eliminate an imbalance between the margins of the degrees.

2. The wavelength cross-connect device according to claim 1 , wherein the control unit is configured to perform control to determine the splitting ratios of the variable splitting-ratio couplers in such a manner that each of the margins of the output sides of the degrees is close or equal to an average value of the smallest margins of the degrees.

3. The wavelength cross-connect device according to claim 1 , wherein:
first WSSs configured to provide N outputs from one input that is an optical signal are connected to the input sides of the respective degrees and first variable splitting-ratio couplers that each split one input into M splits, M being smaller than N, are cascade-connected to each of the connected first WSSs for the respective degrees; and
second variable splitting-ratio couplers configured to provide one output by combining M inputs are connected to M output ports of each of the cascade-connected first variable splitting-ratio couplers, and second WSSs that each configured to integrate output ports of relevant second variable splitting-ratio couplers of the connected second variable splitting-ratio couplers into one output and provide the respective one outputs to the output sides of the respective degrees are cascade-connected to the respective relevant second variable splitting-ratio couplers.

4. The wavelength cross-connect device according to claim 1 , wherein:
first variable splitting-ratio couplers that each configured to split one input that is an optical signal into M splits are connected to the input sides of the respective degrees, and first WSSs that each configured to provide N outputs from one input are cascade-connected to each of the connected first variable splitting-ratio couplers for the respective degrees; and
second WSSs configured to provide one output from N inputs are connected to output ports of the cascade-connected first WSSs and second variable splitting-ratio couplers configured to combine M output ports of relevant second WSSs of the connected second WSSs into one output and provide the respective one outputs to the output sides of the respective degrees are cascade-connected to the respective relevant second WSSs.

5. A splitting ratio change method for a wavelength cross-connect device for performing a relay by splitting optical signals transmitted from input sides of a plurality of degrees each provided by optical fibers, via respective optical couplers and outputting the split optical signals to output sides of the plurality of degrees via respective WSSs,
the wavelength cross-connect device using a variable splitting-ratio coupler whose splitting ratio that is a ratio of optical signal power losses in splitting an optical signal is variable is used, as each of the optical couplers,
the wavelength cross-connect device including a control unit that performs control to change the splitting ratios of the variable splitting-ratio couplers in such a manner as to eliminate an imbalance between optical signal-to-noise ratio margins of the output sides of the degrees in which a plurality of optical paths transmitting the respective optical signals subsequent to the splitting extend,
the method comprising causing the control unit to perform:
a step of calculating the respective margins for the plurality of optical paths transmitting the optical signals subsequent to the splitting via the variable splitting-ratio couplers, for the output sides of the respective degrees; and
a step of performing control to, based on respective smallest margins of the degrees, the smallest margins being obtained from all the margins calculated for the output sides of the respective degrees, change the splitting ratios of the variable splitting-ratio couplers in such a manner as to eliminate an imbalance between the margins of the degrees.

6. The splitting ratio change method according to claim 5 , wherein the control unit is configured to perform control to determine the splitting ratios of the variable splitting-ratio couplers in such a manner that each of the margins of the output sides of the degrees is close or equal to an average value of the smallest margins of the degrees.

7. The splitting ratio change method according to claim 5 , wherein:
first WSSs configured to provide N outputs from one input that is an optical signal are connected to the input sides of the respective degrees and first variable splitting-ratio couplers that each split one input into M splits, M being smaller than N, are cascade-connected to each of the connected first WSSs for the respective degrees; and
second variable splitting-ratio couplers configured to provide one output by combining M inputs are connected to M output ports of each of the cascade-connected first variable splitting-ratio couplers, and second WSSs that each configured to integrate output ports of relevant second variable splitting-ratio couplers of the connected second variable splitting-ratio couplers into one output and provide the respective one outputs to the output sides of the respective degrees are cascade-connected to the respective relevant second variable splitting-ratio couplers.

8. The splitting ratio change method according to claim 5 , wherein:
first variable splitting-ratio couplers configured to split one input that is an optical signal into M splits are connected to the input sides of the respective degrees, and first WSSs that each configured to provide N outputs from one input are cascade-connected to each of the connected first variable splitting-ratio couplers for the respective degrees; and
second WSSs configured to provide one output from N inputs are connected to output ports of the cascade-connected first WSSs and second variable splitting-ratio couplers that each configured to combine M output ports of relevant second WSSs of the connected second WSSs into one output and provide the respective one outputs to the output sides of the respective degrees are cascade-connected to the respective relevant second WSSs.

9. A non-transitory computer readable medium storing a program for making a computer that is a wavelength cross-connect device that performs a relay by splitting optical signals transmitted from a plurality of degrees each provided by optical fibers, via respective optical couplers and outputting the split opti

Assignees

• Nippon Telegraph & Telephone

Inventors

• Kawahara Hiroki
• Seki Takeshi

Classifications

• H04B10/291

  in which processing or amplification is carried out without conversion of the main signal from optical form · CPC title

• H04J3/08

  Intermediate station arrangements, e.g. for branching, for tapping-off · CPC title

• H04Q3/52

  using static devices in switching stages, e.g. electronic switching arrangements · CPC title

• H04J3/00

  Time-division multiplex systems (H04J14/00 takes precedence; relay systems H04B7/14; selecting techniques H04Q) · CPC title

• H04Q2011/005

  Arbitration and scheduling · CPC title