System and method for modularly scalable architecture for optical networks

• US 20060045528A1
• Filed: 08/27/2004
• Published: 03/02/2006
• Est. Priority Date: 08/27/2004
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Network Communications Incorporated (Fujitsu Limited)
• Inventors: Bihon, Daniel, Gumaste, Ashwin Anil
• Granted Patent: US 7,450,851 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 14/0206 Express channels arrangements
• 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 14/0219 Modular or upgradable architectures

Abstract

A system and method for modularly scalable architecture for optical networks are provided. In one embodiment, a node for an optical network comprises a plurality of in-line switches connected to an optical ring and operable in a first state to both pass an optical signal received from the optical ring to an associated coupler and pass an optical signal received from the associated coupler to the optical ring. The optical signal carries traffic in a plurality of channels. A drop coupler is coupled to a first in-line switch and is operable to receive an optical signal from the in-line switch where the switch is in the first state, pass a first copy of the optical signal back to the in-line switch for passing to the optical ring, and drop a second copy of the optical signal to a distributing element. The distributing element is operable to receive the second copy and pass traffic in one or more channels of the second copy. A filter is operable to reject one or more channels of the first copy to generate a passthrough signal. A combining element is operable to receive traffic in one or more channels to be added to the optical ring and combine the received traffic to generate an add signal. An add coupler is coupled to a second in-line switch and is operable to receive the passthrough signal from the second in-line switch when the switch is in the first state, add the add signal to the passthrough signal to generate a combined signal, and pass the combined signal to the second in-line switch for passing to the optical ring.

Claims

1. A node for an optical network, comprising:

a plurality of in-line switches connected to an optical ring and operable in a first state to both pass an optical signal received from the optical ring to an associated coupler and pass an optical signal received from the associated coupler to the optical ring, the optical signal carrying traffic in a plurality of channels;

a drop coupler coupled to a first in-line switch and operable to receive an optical signal from the in-line switch where the switch is in the first state, pass a first copy of the optical signal back to the in-line switch for passing to the optical ring, and drop a second copy of the optical signal to a distributing element;

the distributing element operable to receive the second copy and pass traffic in one or more channels of the second copy;

a filter operable to reject one or more channels of the first copy to generate a passthrough signal;

a combining element operable to receive traffic in one or more channels to be added to the optical ring and to combine the received traffic to generate an add signal; and

an add coupler coupled to a second in-line switch and operable to receive the passthrough signal from the second in-line switch when the switch is in the first state, add the add signal to the passthrough signal to generate a combined signal, and pass the combined signal to the second in-line switch for passing to the optical ring.

2. The node of claim 1, wherein the one or more rejected channels comprise the one or more channels in which traffic is added by the combining element.

3. The node of claim 1, wherein the distributing element comprises a demultiplexer.

4. The node of claim 1, wherein the distributing element comprises a wavelength-selective switch.

5. The node of claim 1, wherein the combining element comprises a multiplexer.

6. The node of claim 1, wherein the combining element comprises a wavelength-selective switch.

7. The node of claim 1, wherein the filter comprises a wavelength blocker.

8. The node of claim 1, further comprising a third in-line switch coupled to the optical ring and the filter and operable to both pass the first copy from the optical ring to the filter and to pass the passthrough signal received from the filter to the optical ring when in the first state.

9. The node of claim 1, further comprising a cross connect coupled to the distributing element, the cross connect comprising a plurality of input ports for receiving the traffic passed by the distributing element and a plurality of output ports and operable to cross connect traffic from one or more input ports to one or more output ports.

10. The node of claim 1, wherein the combining element comprises a first combining element, the optical ring comprising a first optical ring, the distributing element operable to pass at least one of the one or more channels to second combining element associated with a second optical ring.

11. The node of claim 1, wherein the distributing element comprises a first distributing element, the optical ring comprising a first optical ring, the combining element operable to receive traffic in at least one channel from a second combining element associated with a second optical ring.

12. The node of claim 9, wherein the cross connect comprises a first cross connect, further comprising a second cross connect coupled to the combining element, the first cross connect operable to pass traffic in at least one channel to the second cross connect.

13. The node of claim 1, further comprising a fourth in-line switch operable in a second state to pass through an optical signal.

14. An optical network, comprising:

an optical ring; and

a plurality of nodes, each node comprising;

a plurality of in-line switches connected to an optical ring and operable in a first state to both pass an optical signal received from the optical ring to an associated coupler and pass an optical signal received from the associated coupler to the optical ring, the optical signal carrying traffic in a plurality of channels;

a drop coupler coupled to a first in-line switch and operable to receive an optical signal from the in-line switch where the switch is in the first state, pass a first copy of the optical signal back to the in-line switch for passing to the optical ring, and drop a second copy of the optical signal to a distributing element;

the distributing element operable to receive the second copy and pass traffic in one or more channels of the second copy;

a filter operable to reject one or more channels of the first copy to generate a passthrough signal;

a combining element operable to receive traffic in one or more channels to be added to the optical ring and to combine the received traffic to generate an add signal; and

an add coupler coupled to a second in-line switch and operable to receive the passthrough signal from the second in-line switch when the switch is in the first state, add the add signal to the passthrough signal to generate a combined signal, and pass the combined signal to the second in-line switch for passing to the optical ring.

15. The optical network of claim 14, wherein the one or more rejected channels comprise the one or more channels in which traffic is added by the combining element.

16. The optical network of claim 14, wherein the distributing element comprises a demultiplexer.

17. The optical network of claim 14, wherein the distributing element comprises a wavelength selective switch.

18. The optical network of claim 14, wherein the combining element comprises a multiplexer.

19. The optical network of claim 14, wherein the combining element comprises a wavelength-selective switch.

20. The optical network of claim 14, wherein the filter comprises a wavelength blocker.

21. The optical network of claim 14, the nodes further comprising a third in-line switch coupled to the optical ring and the filter and operable to both pass the first copy from the optical ring to the filter and to pass the passthrough signal received from the filter to the optical ring in the first state when in the first state.

22. The optical network of claim 14, the nodes further comprising a cross connect coupled to the distributing element, the cross connect comprising a plurality of input ports for receiving the traffic passed by the distributing element and a plurality of output ports and operable to cross connect traffic from one or more input ports to one or more output ports.

23. The optical network of claim 14, the nodes further comprising a fourth in-line switch operable in a second state to pass through an optical signal.

24. The optical network of claim 14, wherein the combining element comprises a first combining element, the optical ring comprising a first optical ring, the distributing element operable to pass at least one of the one or more channels to second combining element associated with a second optical ring.

25. The optical network of claim 14, wherein the distributing element comprises a first distributing element, the optical ring comprising a first optical ring, the combining element operable to receive traffic in at least one channel from a second combining element associated with a second optical ring.

26. The optical network of claim 22, wherein the cross connect comprises a first cross connect, the nodes further comprising a second cross connect coupled to the combining element, the first cross connect operable to pass traffic in at least one channel to the second cross connect.

27. A node for an optical network, comprising:

a plurality of in-line switches connected to an optical ring and operable in a first state to both pass an optical signal received from the optical ring to an associated distributing element and pass an optical signal received from the associated distributing element to the optical ring, the optical signal carrying traffic in a plurality of channels;

a distributing element coupled to a first in-line switch in the first state and operable to receive an optical signal from the in-line switch, pass traffic in a first set of one or more channels of the optical signal back to the in-line switch for passing to the optical ring, and pass traffic in a second set of one or more channels to output leads of the distributing element; and

a combining element coupled to a second in-line switch in the first state and operable to receive the traffic in the first set of channels from the second in-line switch and traffic in at least one of the second set of channels from input leads of the combining element, add the traffic in the first and second sets of channels to generate a combined signal, and pass the combined signal to the second in-line switch for passing to the optical ring.

28. The node of claim 27, wherein both the distributing and combining elements each comprise a wavelength-selective switch.

29. A node for an optical network, comprising:

a drop coupler coupled to an optical ring and operable to receive an optical signal from the optical ring, pass a first copy of the optical signal through to the optical ring, and drop a second copy of the optical signal to a first wavelength-selective switch;

the first wavelength-selective switch operable to receive the second copy from the drop coupler, pass traffic in at least a first channel or subband of the second copy to a second wavelength-selective switch, and pass traffic in at least a second channel or subband of the second copy to a third wavelength-selective switch, wherein the first and second channels and subbands are different;

the second wavelength-selective switch operable to pass one or more channels of the first subband; and

the third wavelength-selective switch operable to pass one or more channels of the second subband.