Optical add/drop multiplexer

• US 20060034610A1
• Filed: 08/16/2005
• Published: 02/16/2006
• Est. Priority Date: 08/16/2004
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Miura, Akira, Isomura, Akihiko, Ooi, Hiroki, Terahara, Takafumi, Rasmussen, Jens C., Akiyama, Yuichi
• Granted Patent: US 7,792,428 B2
• Time in Patent Office: Days
• US Class Current: 398/83
• CPC Class Codes: H04J 14/0204 Broadcast and select arrangements, e.g. with an optical splitter at the input before adding or dropping
• CPC Class Codes: H04J 14/0205 Select and combine arrangements, e.g. with an optical combiner at the output after adding or dropping
• CPC Class Codes: H04J 14/0206 Express channels arrangements
• CPC Class Codes: H04J 14/0208 Interleaved arrangements
• CPC Class Codes: H04J 14/0209 Multi-stage arrangements, e.g. by cascading multiplexers or demultiplexers
• CPC Class Codes: H04J 14/0212 using optical switches or wavelength selective switches [WSS]
• CPC Class Codes: H04J 14/0213 Groups of channels or wave bands arrangements
• CPC Class Codes: H04J 14/0217 Multi-degree architectures, e.g. having a connection degree greater than two
• CPC Class Codes: H04J 14/0219 Modular or upgradable architectures
• CPC Class Codes: H04J 14/022 For interconnection of WDM optical networks
• CPC Class Codes: H04J 14/0221 Power control, e.g. to keep the total optical power constant
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 2011/0009 using wavelength filters
• CPC Class Codes: H04Q 2011/0016 using wavelength multiplexing or demultiplexing
• CPC Class Codes: H04Q 2011/0032 using static wavelength routers (e.g. arrayed waveguide grating router [AWGR] )
• CPC Class Codes: H04Q 2011/0039 Electrical control
• CPC Class Codes: H04Q 2011/0075 Wavelength grouping or hierarchical aspects
• CPC Class Codes: H04Q 2011/0083 Testing; Monitoring

Abstract

A core unit arranged in a transmission path includes a through path for causing an input signal to an input port to pass through to an output port, a drop-side port 25a that drops the input signal having a predetermined wavelength, and an add-side port 25b that adds channel having a predetermined wavelength to the input light.

Claims

1. An optical add/drop multiplexer for switching a optical path, and dropping or adding channel that has a predetermined wavelength, the optical path for changing an input signal that has multiplexed wavelengths and that is input to an input port, to an output signal for each wavelength, the output signal being led to output ports for a plurality of routes in each transmission path, the optical add/drop multiplexer comprising:

a core unit that includes

a through path that lets the input signal pass through to the output port;

a drop port for dropping the input signal that has a predetermined wavelength; and

an add port for adding the channel to the input signal.

2. The optical add/drop multiplexer according to claim 1, further comprising:

a drop unit that is connected to the drop port, that demultiplexes the input signal dropped from the drop port for each wavelength, and that outputs a plurality of signals that are formed as a result of demultiplexing.

3. The optical add/drop multiplexer according to claim 2, wherein

the drop port is provided in plurality,

a part of the drop ports is connected to the drop unit, and

another part of the drop ports is connected to a wavelength cross-connect.

4. The optical add/drop multiplexer according to claim 1, wherein the drop port is an output port of a 1×

N optical coupler, where 1 is the number of input, and N is a positive integer and represents the number of output.

5. The optical add/drop multiplexer according to claim 1, wherein the drop port is an output port of a 1×

N wavelength selective switch, where 1 is the number of input, and N is a positive integer and represents the number of output.

6. The optical add/drop multiplexer according to claim 1, further comprising:

an add unit that is connected to the add port, that multiplexes the signal light that has a plurality of wavelengths for each of the wavelengths, the signal light to be added to the add port.

7. The optical add/drop multiplexer according to claim 6, wherein

the add port is provided in plurality,

a part of the add ports is connected to the add unit, and

another part of the add ports is connected to a wavelength cross-connect.

8. The optical add/drop multiplexer according to claim 1, wherein the add port is an input port of an M×

1 optical coupler, where M is a positive integer and represents the number of input, and 1 is the number of output.

9. The optical add/drop multiplexer according to claim 1, wherein the add port is an input port of an M×

1 wavelength selective switch, where M is a positive integer and represents the number of input, and 1 is the number of output.

10. The optical add/drop multiplexer according to claim 1, wherein the core unit is provided by the same number as the number of the routes, and

each of the core units includes

a 1×

N wavelength selective switch that has N pieces of drop ports, where 1 is the number of input, and N is a positive integer and represents the number of output; and

an M×

1 wavelength selective switch that has M pieces of add ports, where M is a positive integer and represents the number of input, and 1 is the number of output, wherein

the drop ports of the 1×

N wavelength selective switch in one of the core units and the add ports of the M×

1 wavelength selective switch in another one of the core units are connected to be used for a wavelength cross-connect.

11. The optical add/drop multiplexer according to claim 1, wherein the core unit includes

a 1×

N optical coupler that receives the input signal and hat has N pieces of output ports, where 1 is the number of input, and N is a positive integer and represents the number of output;

an M×

1 optical coupler that has M pieces of input ports and that outputs the input signal as the output signal, where M is a positive integer and represents the number of input, and 1 is the number of output;

a through path that is formed by connecting one of the output ports of the 1×

N optical coupler to one of the input ports of the M×

1 optical coupler; and

a wavelength blocker that is provided in the through path.

12. The optical add/drop multiplexer according to claim 1, wherein the core unit includes

a 1×

N optical coupler that receives the input signal and that has N pieces of output ports, where 1 is the number of input, and N is a positive integer and represents the number of output;

an M×

1 optical coupler that has M pieces of input ports and that outputs the input signal as the output signal, where M is a positive integer and represents the number of input, and 1 is the number of output;

a through path that is formed by connecting one of the output ports of the 1×

N optical coupler to one of the input ports of the M×

1 optical coupler;

a 1×

N wavelength selective switch that is connected to one of the output ports of the 1×

N optical coupler and that has N pieces of drop ports; and

an M×

1 wavelength selective switch that is connected to one of the input ports of the M×

1 optical coupler and that has M pieces of add ports.

13. The optical add/drop multiplexer according to claim 1, wherein the core unit includes

a 1×

N wavelength selective switch that receives the input signal and that has N pieces of output ports, where 1 is the number of input, and N is a positive integer and represents the number of output;

an N×

1 optical coupler that has N pieces of input ports and that outputs the input signal as the output signal, where 1 is the number of input, and N is a positive integer and represents the number of output;

a through path that is formed by connecting one of the output ports of the 1×

N optical coupler to one of the input ports of the N×

1 optical coupler; and

an M×

1 wavelength selective switch that is connected to one of the input ports of the N×

1 optical coupler and that has M pieces of the add ports, where M is a positive integer and represents the number of input, and 1 is the number of output.

14. The optical add/drop multiplexer according to claim 1, wherein the core unit includes

a 1×

N wavelength selective switch that receives the input signal and that has N pieces of output ports, where 1 is the number of input, and N is a positive integer and represents the number of output;

an M×

1 wavelength selective switch that has M pieces of input ports and that outputs the input signal as the output signal, where M is a positive integer and represents the number of input, and 1 is the number of output; and

a through path that is formed by connecting one of the output ports of the 1×

N wavelength selective switch to one of the input ports of the M×

1 wavelength selective switch.

15. The optical add/drop multiplexer according to claim 1, comprising a pair of interleavers that changes a wavelength spacing of the input signal, and that is provided in the add port and the drop port.

16. The optical add/drop multiplexer according to claim 15, wherein the core unit includes

a first core unit that includes

a wavelength selective switch that is provided between the pair of interleavers, and that outputs the input signal to the drop port, the input signal of a first wavelength group having a wavelength spacing from among wavelength spacings that are changed by the interleaver, and

a wavelength selective switch that receives the signal;

and

a second core unit for extension that includes

a wavelength selective switch that is additionally connected between the interleavers, and that outputs the input signal to the drop port, the input signal of a second wavelength group having a wavelength spacing same as the wavelength spacing that is changed by the interleaver and that is input to the first core unit, and

a wavelength selective switch that receives the signal.

17. The optical add/drop multiplexer according to claim 2, wherein the drop unit includes any one of an optical demultiplexer for a fixed wavelength, a 1×

N wavelength selective switch, where 1 is the number of input, and N is a positive integer and represents the number of output, a grouping filter, an optical coupler, and a wavelength variable filter.

18. The optical add/drop multiplexer according to claim 6, wherein the add unit includes any one of an optical multiplexer for a fixed wavelength, an M×

1 wavelength selective switch, where M is a positive integer and represents the number of input, and 1 is the number of output, a grouping filter, and an optical coupler.

19. The optical add/drop multiplexer according to claim 17, wherein the grouping filter is an interleaver, and limitation on the number of wavelengths for use when using the grouping filter is resolved.

20. The optical add/drop multiplexer according to claim 18, wherein the grouping filter is an interleaver, and limitation on the number of wavelengths for use when using the grouping filter is resolved.

21. The optical add/drop multiplexer according to claim 17, wherein the grouping filter is a band division filter, and limitation on the number of wavelengths for use when using the grouping filter is resolved.

22. The optical add/drop multiplexer according to claim 18, wherein the grouping filter is a band division filter, and limitation on the number of wavelengths for use when using the grouping filter is resolved.

23. The optical add/drop multiplexer according to claim 17, wherein the grouping filter is an arrayed waveguide grating, and limitation on the number of wavelengths for use when using the grouping filter is resolved.

24. The optical add/drop multiplexer according to claim 18, wherein the grouping filter is an arrayed waveguide grating, and limitation on the number of wavelengths for use when using the grouping filter is resolved.

25. The optical add/drop multiplexer according to claim 1, comprising a power adjuster that adjusts power of the signal, wherein the power adjuster is provided in at least one of the through path, the drop port, and the add port.

26. The optical add/drop multiplexer according to claim 1, wherein the drop port is provided in plurality, at least one of the drop ports is set as a port for a wavelength cross-connect, and an expansion element for output that is used to increase the number of ports is connectable to the port for a wavelength cross-connect.

27. The optical add/drop multiplexer according to claim 1, wherein the add port is provided in plurality, at least one of the input ports is set as a port for a wavelength cross-connect, and an expansion element for input that is used to increase the number of ports is connectable to the port for a wavelength cross-connect.

28. The optical add/drop multiplexer according to claim 26, wherein either one of a 1×

N wavelength selective switch and an optical coupler is connected as the expansion element for output, where 1 is the number of input, and N is a positive integer and represents the number of output.

29. The optical add/drop multiplexer according to claim 27, wherein either one of an M×

1 wavelength selective switch and an optical coupler is connected as the expansion element for input, where M is a positive integer and represents the number of input, and 1 is the number of output.

30. The optical add/drop multiplexer according to claim 28, wherein the optical coupler is exclusively provided only in either one of the expansion element for output and the expansion element for input.

31. The optical add/drop multiplexer according to claim 29, wherein the optical coupler is exclusively provided only in either one of the expansion element for output and the expansion element for input.

32. The optical add/drop multiplexer according to claim 30, wherein the core unit includes an M×

1 wavelength selective switch that includes M pieces of input ports and that outputs the input signal as the output signal, where M is a positive integer and represents the number of input, and 1 is the number of output.

33. The optical add/drop multiplexer according to claim 31, wherein the core unit includes the M×

1 wavelength selective switch that includes M pieces of input ports and that outputs the input signal as the output signal.

34. The optical add/drop multiplexer according to claim 1, wherein the core unit includes

a first 1×

2 optical coupler that receives the input signal and that has two pieces of output ports;

an M×

1 wavelength selective switch that has M pieces of input ports and that outputs the input signal as the output signal, where M is a positive integer and represents the number of input, and 1 is the number of output;

a through path that is formed by connecting one of the output ports of the first 1×

2 optical coupler to one of the of input ports of the M×

1 wavelength selective switch;

a second 1×

2 optical coupler that has two pieces of output ports that are connected to another of the output ports of the first 1×

2 optical coupler; and

a 1×

N wavelength selective switch that has N pieces of output ports, and that is connected to one of the output ports of the second 1×

2 optical coupler, where 1 is the number of input, and N is a positive integer and represents the number of output, wherein

another of the output ports of the second 1×

2 optical coupler is set as a port for a wavelength cross-connect, and

a part of the input ports of the M×

1 wavelength selective switch is set as a port for a wavelength cross-connect.

35. The optical add/drop multiplexer according to claim 1, wherein the core unit includes

a 1×

2 optical coupler that receives the input signal and that has two pieces of output ports, where 1 is the number of input and 2 is the number of output;

an M×

1 wavelength selective switch that has M pieces of input ports and that outputs the input signal as the output signal, where M is a positive integer and represents the number of input, and 1 is the number of output;

a through path that is formed by connecting one of the output ports of the 1×

2 optical coupler to one of the input ports of the M×

1 wavelength selective switch; and

a 1×

N optical coupler that has N pieces of output ports, where 1 is the number of input, and N is a positive integer and represents the number of output, and that is connected to another of the output ports of the 1×

2 optical coupler, wherein

one of the output ports of the 1×

N optical coupler is set as a port for a wavelength cross-connect, and

a part of the input ports of the M×

1 wavelength selective switch is set as a port for a wavelength cross-connect.