Optical cross-connect switch using programmable multiplexers/demultiplexers

• US 6,738,540 B2
• Filed: 08/31/2001
• Issued: 05/18/2004
• Est. Priority Date: 06/22/2001
• Status: Expired due to Term

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Marom, Dan Mark
• Primary Examiner(s): Nasri, Javaid H.
• Assistant Examiner(s): LE, THANH TAM T
• Application Number:
  US09/944,801
• Publication Number:
  US 20020197000A1
• Time in Patent Office: 991 Days
• Field of Search: 385/16, 385/17, 385/18, 385/24, 385/37, 398/56, 398/57, 398/68, 398/69, 398/79
• US Class Current: 385/17
• 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 14/0212 using optical switches or wavelength selective switches [WSS]
• CPC Class Codes: H04J 14/0217 Multi-degree architectures, e.g. having a connection degree greater than two
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 2011/0016 using wavelength multiplexing or demultiplexing

Abstract

An optical cross connect switch includes a programmable demultiplexer placed on every input transmission port, a programmable multiplexer placed on every output transmission port, and a linking fiber between every programmable demultiplexer and multiplexer in the system. The programmable demultiplexers and multiplexers handle internally all the optical communication channels, and can route any specified optical channel from an input port to the desired output port. Advantageously, the arrangement can send several input channels to the same output port, and can efficiently handle a large optical communication channel count, offer a scalable cost-effective solution for expanding switching capacity, and reduce the fiber interconnection count between switch modules. When a new optical communication system is added to the node, it requires only that a programmable multiplexer and demultiplexer be placed on its output and input fibers, respectively, and fibers connected to its neighboring programmable multiplexers and demultiplexers. The arrangement thus scales proportionally with the number of input line systems to the switch, regardless of the number of optical channels, and thus provides a pay as you grow solution. The cross connect can be modified to provide add-drop functionality, and some of the programmable multiplexers/demultiplexers can be replaced with passive or conventional devices.

Claims

1. A cross connect for

(i) receiving (a) at least one input WDM signal cumulatively comprising a first plurality of optical wavelength channels from a respective at least one remote optical communication system and (b) a second plurality of added optical wavelength channels, and

(ii) generating (c) at least one output WDM signal cumulatively comprising a third plurality of optical wavelength channels comprising some of the optical wavelength channels in said first and second pluralities of optical wavelength channels, for transmission to a respective at least one remote optical communication system and (d) a fourth plurality of dropped optical wavelength channels contained in said first plurality of optical wavelength channels, for transmission to a local destination,

said cross connect comprising

a first plurality of programmable demultiplexers, each arranged to receive said at least one input WDM signal,

a first plurality of programmable multiplexers, each arranged to provide said at least one output WDM signal,

a second plurality of demultiplexers arranged to provide said fourth plurality of dropped optical wavelength channels,

a second plurality of multiplexers arranged to receive said second plurality of added optical wavelength channels, and

a plurality of linking fibers arranged to interconnect (a) an output from each one of the programmable demultiplexers in said first plurality of programmable demultiplexers, to the input of one of the demultiplexers in said second plurality of demultiplexers, (b) an output from each one of the programmable demultiplexers in said first plurality of programmable demultiplexers, to the input of one of the programmable multiplexers in said first plurality of programmable multiplexers, and (c) an output from each one of the multiplexers in said second plurality of multiplexers, to the input of one of the programmable multiplexers in said first plurality of programmable multiplexers.

2. The invention defined in claim 1 wherein said cross connect further includes first and second auxiliary cross connect switches, and wherein

said first auxiliary cross connect switch is arranged to concentrate the outputs of said second plurality of demultiplexers to generate said fourth plurality of dropped optical wavelength channels, and

said second auxiliary cross connect switch is arranged to distribute said second plurality of added optical wavelength channels for input to said second plurality of multiplexers.

3. The invention defined in claim 1 wherein said programmable demultiplexers each have (a) a plurality of programmable demultiplexer output ports, and (b) a programmable demultiplexer input port for receiving said input WDM signal containing multiple optical wavelength channels, and wherein each of said programmable demultiplexers is arranged to independently distribute said multiple optical wavelength channels to said programmable demultiplexer output ports.

4. The invention defined in claim 1 wherein said programmable multiplexers each have (a) a plurality of programmable multiplexer input ports for independently receiving multiple optical wavelength channels, and (b) a programmable multiplexer output port, and wherein each of said programmable multiplexers is arranged to combine said multiple optical wavelength channels to generate said WDM signal at said programmable multiplexer output port.

5. An optical cross-connect switch, comprising:

one or more programmable demultiplexers, each having a demultiplexer input port and a plurality of demultiplexer output ports;

one or more primary combiners, each having a plurality of combiner input ports and a combiner output port; and

one or more individual linking fibers, each connecting a demultiplexer output port to a combiner input port, wherein;

each programmable demultiplexer is adapted to (i) receive a control signal and (ii) for each of one or more optical wavelength channels applied to the demultiplexer input port, route the channel to any demultiplexer output port selected based on the control signal; and

an optical wavelength channel applied to a demultiplexer input port is routed to a desired combiner output port via a corresponding programmable demultiplexer, a corresponding linking fiber, and a corresponding primary combiner.

6. The invention defined in claim 5, wherein said one or more primary combiners are programmable multiplexers.

7. The invention defined in claim 5, wherein said one or more primary combiners are passive combiners.

8. The switch of claim 5, further comprising one or more add combiners, each having a plurality of combiner input ports and a combiner output port, wherein, for each add combiner, the combiner output port is connected to an input port of a corresponding primary combiner.

9. The switch of claim 8, wherein each add combiner is a programmable multiplexer.

10. The switch of claim 8, wherein, for each add combiner, each combiner input port is connected to a distributor cross-connect switch.

11. The switch of claim 5, further comprising one or more drop splitters, each having a splitter input port and a plurality of splitter output ports, wherein, for each drop splitter, the splitter input port is connected to an output port of a corresponding programmable demultiplexer.

12. The switch of claim 11, wherein each drop splitter is a programmable demultiplexer.

13. The switch of claim 11, wherein, for each drop splitter, each splitter output port is connected to a concentrator cross-connect switch.

14. An optical cross-connect switch, comprising:

one more primary splitters, each having a splitter input port and a plurality of splitter output ports;

one or more programmable multiplexers, each having a plurality of multiplexer input ports and a multiplexer output port; and

one or more individual linking fibers, each connecting a splitter output port to a multiplexer input port, wherein;

each programmable multiplexer is adapted to (i) receive a control signal and (ii) for each of one or more optical wavelength channels, establish, based on the control signal, a unique pathway from any selected multiplexer input port to the multiplexer output port; and

an optical wavelength channel applied to a splitter input port is routed to a desired multiplexer output port via a corresponding primary splitter, a corresponding linking fiber, and a corresponding programmable multiplexer.

15. The switch of claim 14, wherein each programmable multiplexer is adapted to prevent combining at the multiplexer output port two optical wavelength channels having a same wavelength when said two channels are applied to two different multiplexer input ports.

16. The invention defined in claim 14, wherein said one or more primary splitters are passive splitters.

17. The switch of claim 14, further comprising one or more add combiners, each having a plurality of combiner input ports and a combiner output port, wherein, for each add combiner, the combiner output port is connected to an input port of a corresponding programmable multiplexer.

18. The switch of claim 17, wherein each add combiner is a programmable multiplexer.

19. The switch of claim 17, wherein the input ports of each add combiner are connected to a distributor cross-connect switch.

20. The switch of claim 14, further comprising one or more drop splitters, each having a splitter input port and a plurality of splitter output ports, wherein, for each drop splitter, the splitter input port is connected to an output port of a corresponding primary splitter.

21. The switch of claim 20, wherein each drop splitter is a programmable demultiplexer.

22. The switch of claim 20, wherein, for each drop splitter, each splitter output port is connected to a concentrator cross-connect switch.

23. The switch of claim 20, further comprising one or more add combiners, each having a plurality of combiner input ports and a combiner output port, wherein:

for each add combiner, the combiner output port is connected to an input port of a corresponding programmable multiplexer;

each add combiner is a programmable multiplexer;

each drop splitter is a programmable demultiplexer; and

each primary splitter is a programmable demultiplexer.

24. The switch of claim 23 wherein:

the input ports of each add combiner are connected to a distributor cross-connect switch; and

for each drop splitter, each splitter output port is connected to a concentrator cross-connect switch.