Optical wavelength cross connect architectures using wavelength routing elements

• US 20030170025A1
• Filed: 03/08/2002
• Published: 09/11/2003
• Est. Priority Date: 03/08/2002
• Status: Active Grant

• Current Assignee: Altera Corporation (Intel Corporation)
• Original Assignee: Network Photonics, Inc.
• Inventors: Morley, George David, Iraschko, Rainer, Barthel, Dirk, Weverka, Robert T., Bortolini, Edward J.
• Granted Patent: US 7,079,723 B2
• Time in Patent Office: Days
• US Class Current: 398/50
• 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 14/0209 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 14/0282 WDM tree architectures
• CPC Class Codes: H04J 14/0297 Optical equipment protection
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 2011/0016 using wavelength multiplexing or demultiplexing
• CPC Class Codes: H04Q 2011/0024 using space switching
• CPC Class Codes: H04Q 2011/0026 using free space propagation (e.g. lenses, mirrors)
• CPC Class Codes: H04Q 2011/0032 using static wavelength routers (e.g. arrayed waveguide grating router [AWGR] )
• CPC Class Codes: H04Q 2011/0043 Fault tolerance
• CPC Class Codes: H04Q 2011/0052 Interconnection of switches
• CPC Class Codes: H04Q 2011/0075 Wavelength grouping or hierarchical aspects

Abstract

An optical wavelength cross connect is provided to receive multiple input optical signals that each have multiple spectral bands and to transmit multiple output optical signals that each have one or more of those spectral bands. The optical wavelength cross connect includes multiple wavelength routing elements, which are optical components that selectively route wavelength components between one optical signal and multiple optical signals in either direction according to a configurable state. As used within the optical wavelength cross connect, each of the wavelength routing elements receives at least one optical signal corresponding to one of the input optical signals. A mapping of the spectral bands to the output optical signals is determined by the states of the wavelength routing elements.

Claims

1. An optical wavelength cross connect for receiving a plurality of input optical signals each having a plurality of spectral bands and transmitting a plurality of output optical signals each having one or more of the spectral bands, the optical wavelength cross connect comprising:

a first plurality of wavelength routing elements, each such wavelength routing element adapted for selectively routing wavelength components between a first optical signal and a plurality of second optical signals according to a configurable state of such wavelength routing element, wherein each of the first plurality of wavelength routing elements is disposed to receive at least one optical signal corresponding to one of the input optical signals,

wherein a mapping of the spectral bands comprised by the plurality of input optical signals to the plurality of output optical signals is determined by the states of the first plurality of wavelength routing elements.

2. The optical wavelength cross connect recited in claim 1 wherein:

at least one of the first plurality of wavelength routing elements is comprised by a protection fabric and the remainder of the first plurality of wavelength routing elements are comprised by a working fabric; and

the optical wavelength cross connect further comprises a plurality of working optical switches each configured to transmit a respective one of the output optical signals either as a working signal received from the working fabric or a protection signal received from the protection fabric.

3. The optical wavelength cross connect recited in claim 2 wherein the working fabric includes a plurality of optical amplifiers, each disposed to amplify one of the working signals prior to transmission to its respective working optical switch.

4. The optical wavelength cross connect recited in claim 2 wherein the protection fabric includes a protection optical switch disposed to transmit the protection signal to one of the working optical switches depending upon a state of the protection optical switch.

5. The optical wavelength cross connect recited in claim 4 wherein the protection fabric further includes an optical amplifier disposed to amplify the protection signal prior to transmission to one of the working optical switches.

6. The optical wavelength cross connect recited in claim 2 further comprising a plurality of optical splitters each disposed to intercept one of the input optical signals and to transmit an equivalent of such one of the input optical signals to each of the first plurality of wavelength routing elements, wherein each wavelength routing element is disposed to receive equivalents corresponding to each of the input optical signals and to transmit the respective working signal depending on the state of such wavelength routing element.

7. The optical wavelength cross connect recited in claim 2 wherein the at least one wavelength routing element comprised by the protection fabric is disposed to receive an equivalent of each of the input signals and to transmit the protection signal with spectral bands corresponding to desired spectral bands on one of the output optical signals depending on the state of that wavelength routing element.

8. The optical wavelength cross connect recited in claim 2 further comprising:

a plurality of optical splitters each disposed to intercept one of the input optical signals and to transmit an equivalent of such one of the input optical signals to one of the first plurality of wavelength routing elements comprised by the working fabric and to transmit each equivalent of the at least one wavelength routing element comprised by the protection fabric; and

a second plurality of wavelength routing elements disposed to transmit the working signals to the working optical switches,

wherein outputs of the each of the first plurality of wavelength routing elements are optically connected an input to each of the second plurality of wavelength routing elements.

9. The optical wavelength cross connect recited in claim 8 wherein the plurality of input optical signals, outputs from each of the first plurality of wavelength routing elements, and inputs to each of the second plurality of wavelength routing elements are equal in number.

10. The optical wavelength cross connect recited in claim 2 wherein the working fabric further comprises a plurality of optical performance monitors disposed to measure optical characteristics of the working signals.

11. The optical wavelength cross connect recited in claim 2 wherein the protection fabric further comprises at least one optical performance monitor disposed to measure optical characteristics of the protection signal.

12. The optical wavelength cross connect recited in claim 1 further comprising a plurality of optical splitters each disposed to intercept one of the input optical signals and to transmit an equivalent of such one of the input optical signals to each of the first plurality of wavelength routing elements, wherein each wavelength routing element is disposed to receive equivalents corresponding to each of the input optical signals and to transmit the respective output optical signal depending on the state of such wavelength routing element.

13. The optical wavelength cross connect recited in claim 1 further comprising a second plurality of wavelength routing elements disposed to transmit the output optical signal, wherein outputs of the each of the first plurality of wavelength routing elements are optically connected with an input to each of the second plurality of wavelength routing elements.

14. The optical wavelength cross connect recited in claim 1 further comprising a plurality of optical performance monitors disposed to measure optical characteristics of the input optical signals.

15. The optical wavelength cross connect recited in claim 1 further comprising a plurality of optical performance monitors disposed to measure optical characteristics of the output optical signals.

16. The optical wavelength cross connect recited in claim 1 further comprising a plurality of optical supervisory channels disposed to drop one or more spectral bands from the input optical signals.

17. The optical wavelength cross connect recited in claim 1 further comprising a plurality of optical supervisory channels disposed to add one or more spectral bands to the output optical signals.

18. The optical wavelength cross connect recited in claim 1 wherein at least one of the first plurality of wavelength routing elements comprises a four-pass wavelength routing element.

19. The optical wavelength cross connect recited in claim 1 wherein at least one of the first plurality of wavelength routing elements comprises a two-pass wavelength routing element.

20. A K×

K optical wavelength cross connect for receiving K input optical signals each having a plurality of spectral bands and transmitting K output optical signals each having one or more of the spectral bands, the optical wavelength cross connect comprising an array of interconnected optical wavelength cross connects, at least one of which is smaller than K×

K and includes a plurality of wavelength routing elements, each such wavelength routing element adapted for selectively routing wavelength components between a first optical signal and a plurality of second optical signals according to a configurable state of such wavelength routing element, wherein a mapping of the spectral bands comprised be the plurality of input optical signals to the plurality of output optical signals is determined by states of the interconnected optical wavelength cross connects.

21. The K×

K optical wavelength cross connect recited in claim 20 wherein the array of interconnected optical wavelength cross connects is configured as a crossbar array.

22. The K×

K optical wavelength cross connect recited in claim 20 wherein the array of interconnected optical wavelength cross connects is configured as a Benes array.

23. The K×

K optical wavelength cross connect recited in claim 20 wherein the array of interconnected optical wavelength cross connects is configured as a Benes array with spatial dilation.

24. The K×

K optical wavelength cross connect recited in claim 20 wherein the array of interconnected optical wavelength cross connects is configured as a Clos array.

25. The K×

K optical wavelength cross connect recited in claim 20 wherein the array of interconnected optical wavelength cross connects comprises;

a first layer having a plurality m of n×

k optical wavelength cross connects;

a second layer having a plurality k of m×

m optical wavelength cross connects; and

a third layer having a plurality m of k×

n optical wavelength cross connects,

wherein each optical wavelength cross connect included in the second layer receives an intermediate input signal from each of the optical wavelength cross connects included in the first layer and transmits an intermediate output signal to each of the optical wavelength cross connects included in the third layer.

26. The K×

K optical wavelength cross connect recited in claim 25 wherein k=2n−

1.

27. A method for distributing a plurality of spectral bands comprised by a plurality of input optical signals onto a plurality of output optical signals, the method comprising:

optically splitting each of the plurality of input optical signals into a plurality of equivalent optical signals;

receiving equivalent optical signals corresponding to each of the plurality of input optical signals at each of a plurality of working wavelength routing elements;

multiplexing selected spectral bands received on the equivalent optical signals with each of the plurality of working wavelength routing elements; and

transmitting respective output optical signals with the multiplexed spectral bands corresponding to the selection of each of the working wavelength routing elements.

28. The method recited in claim 27 further comprising amplifying the multiplexed spectral bands.

29. The method recited in claim 27 further comprising optically monitoring optical characteristics of the multiplexed spectral bands.

30. The method recited in claim 27 further comprising dropping at least one selected spectral band from at least one of the input optical signals before optically splitting that input optical signal.

31. The method recited in claim 27 further comprising adding at least one selected spectral band to at least one of the output optical signals.

32. The method recited in claim 27 further comprising:

receiving equivalent optical signals corresponding to each of the plurality of input optical signals at at least one protection wavelength routing element;

multiplexing selected spectral bands received on the equivalent optical signals with the at least one protection wavelength routing element to produce a protection signal; and

substituting the protection signal for one of the output optical signals to compensate for a fault.

33. A method for distributing a plurality of spectral bands comprised by a plurality of input optical signals onto a plurality of output optical signals, the method comprising:

receiving equivalent optical signals corresponding to each of the plurality of input optical signals at each of a first plurality of working wavelength routing elements;

transmitting a plurality of intermediate optical signals from each of the first plurality of working wavelength routing elements to each of a second plurality of working wavelength routing elements, wherein each of the intermediate optical signals originates at one of the first plurality of working wavelength elements and includes spectral bands selected from the equivalent of the input optical signal received by that wavelength routing element;

multiplexing selected spectral bands received on the intermediate optical signals with each of the second plurality of working wavelength routing elements; and

transmitting respective output optical signals with the multiplexed spectral bands corresponding to the selection of each of the working wavelength routing elements.

34. The method recited in claim 33 further comprising amplifying the multiplexed spectral bands.

35. The method recited in claim 33 further comprising optically monitoring optical characteristics of the multiplexed spectral bands.

36. The method recited in claim 33 wherein the equivalent optical signals consist of the input optical signals.

37. The method recited in claim 33 further comprising:

optically splitting the input optical signals to produce the equivalent optical signals;

receiving equivalent optical signals corresponding to each of the plurality of input optical signals at at least one protection wavelength routing element;

multiplexing selected spectral bands received on the equivalent optical signals with the at least one protection wavelength routing element to produce a protection signal; and

substituting the protection signal for one of the output optical signals to compensate for a fault.