Shared, colorless add/drop configuration for a ROADM network using M×N wavelength switches

• US 8,111,995 B2
• Filed: 02/11/2009
• Issued: 02/07/2012
• Est. Priority Date: 02/11/2009
• Status: Expired due to Fees

• Current Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Original Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Inventors: Wisseman, Philip
• Primary Examiner(s): PASCAL, LESLIE C
• Application Number:
  US12/378,079
• Publication Number:
  US 20100202778A1
• Time in Patent Office: 1,091 Days
• Field of Search: 398 48- 50, 398 83- 85
• US Class Current: 398/83
• CPC Class Codes: G02B 6/2931 Diffractive element operating in reflection
• CPC Class Codes: G02B 6/3556 NxM switch, i.e. regular arrays of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/356 in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links switching polarized beams G02B6/3594; power equalizers G02B6/356 and G02B6/3594; path selecting means H04Q11/0001
• 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

Abstract

A system and method for dynamically adding/dropping wavelengths in a reconfigurable optical add-drop multiplexer (ROADM) transport network is disclosed. The system includes a plurality of M×N wavelength selective switches (WSS) for locally dropping selected wavelengths at a node, where each M×N WSS has M inputs connected to optical fan-out devices in each of M network degrees, and a plurality of M×N wavelength selective switches for locally adding selected wavelengths to a node, where each M×N WSS has M outputs connected to optical fan-in devices in each of M network degrees. Several expedients of M×N wavelength selective switches comprising M switching elements for use in the system are also disclosed.

Claims

1. A system for dynamically adding/dropping wavelengths in a reconfigurable optical add-drop multiplexer transport network having a plurality of optical transponders comprising:

a plurality of optical fan-out devices, each arranged to receive an input signal from a network degree and coupled to a plurality of optical fan-in devices, each optical fan-in device arranged to output a signal to a network degree, the optical fan-out devices comprising a plurality of wavelength selective switches and the optical fan-in devices comprising a plurality of wavelength selective switches, the optical fan-out devices and optical fan-in devices being connected so as to enable signals input from each of a plurality of network degrees to be switched to another network degree of the plurality of network degrees;

a plurality of M×

N wavelength selective switches for locally dropping selected wavelengths, each M×

N wavelength selective switch for locally dropping selected wavelengths having M inputs connected to M network degrees;

a plurality of M×

N wavelength selective switches for locally adding selected wavelengths, each M×

N wavelength selective switch for locally adding selected wavelengths having M outputs connected to M network degrees; and

an optical coupler for adding an additional wavelength selective switch to each network degree.

2. The system of claim 1, wherein each of the M inputs of each M×

N wavelength selective switch for locally dropping selected wavelengths is connected to an optical fan-out device of a network degree.

3. The system of claim 1, wherein each of the M outputs of each M×

N wavelength selective switch for locally adding selected wavelengths is connected to an optical fan-in device of a network degree.

4. The system of claim 1, wherein each M×

N wavelength selective switch comprises M switching elements.

5. The system of claim 4, wherein each M×

N wavelength selective switch further comprises a plurality of focusing optics and a dispersive element disposed relative to the focusing optics.

6. The system of claim 5, wherein the dispersive element in each M×

N wavelength selective switch further comprises a arrayed waveguide grating.

7. The system of claim 6 wherein each M×

N wavelength selective switch further comprises a plurality of arrayed waveguide gratings, and an additional two-dimensional switching element such that a focusing optic is disposed between the M switching elements and the additional two-dimensional switching element.

8. The system of claim 1, wherein each switching element comprises a multidimensional micro-mirror array.

9. The system of claim 8, wherein each multidimensional micro-mirror array comprises a plurality of mirror elements rotatable around first and second orthogonal axes for independent wavelength routing.

10. The A system for dynamically adding/dropping wavelengths in a reconfigurable optical add-drop multiplexer transport network having a plurality of optical transponders, comprising:

a plurality of optical fan-out devices, each arranged to receive an input signal from a network degree and coupled to a plurality of optical fan-in devices, each optical fan-in device arranged to output a signal to a network degree, the optical fan-out devices comprising a plurality of wavelength selective switches and the optical fan-in devices comprising a plurality of wavelength selective switches, the optical fan-out devices and optical fan-in devices being connected so as to enable signals input from each of a plurality of network degrees to be switched to another network degree of the plurality of network degrees;

a plurality of M×

N wavelength selective switches for locally dropping selected wavelengths, each M×

N wavelength selective switch for locally dropping selected wavelengths having M inputs connected to an optical fan-out device in each of M network degrees;

a plurality of M×

N wavelength selective switches for locally adding selected wavelengths, each M×

N wavelength selective switch for locally adding selected wavelengths having M outputs connected to an optical fan-in device in each of M network degrees;

an optical coupler for adding an additional wavelength selective switch to each network degree;

wherein each M×

N wavelength selective switch comprises M switching elements.

11. The system of claim 10, wherein each switching element comprises a multidimensional micro-mirror array.

12. The system of claim 11, wherein each multidimensional micro-mirror array comprises a plurality of mirror elements rotatable around first and second orthogonal axes for independent wavelength routing.

13. The system of claim 11, wherein each M×

N wavelength selective switch further comprises a plurality of focusing optics and a dispersive element disposed relative to the focusing optics.

14. The system of claim 13, wherein the dispersive element in each M×

N wavelength selective switch further comprises an arrayed waveguide grating.

15. The system of claim 14, wherein each M×

N wavelength selective switch further comprises a plurality of arrayed waveguide gratings, and an additional two-dimensional switching element such that a focusing optic is disposed between the M switching elements and the additional two-dimensional switching element.

16. A method for dynamically adding/dropping wavelengths in a reconfigurable optical add-drop multiplexer transport network including a plurality of optical fan-out devices, each arranged to receive an input signal from a network degree and coupled to a plurality of optical fan-in devices, each optical fan-in device arranged to output a signal to a network degree, the optical fan-out devices comprising at least one wavelength selective switch and the optical fan-out devices and optical fan-in devices being connected so as to enable signals input from each of a plurality of network degrees to be switched to another network degree of the plurality of network degrees, the method comprising:

directing signals to a plurality of M×

N wavelength selective switches for locally dropping selected wavelengths, each M×

N wavelength selective switch for locally dropping selected wavelengths having M inputs connected to an optical fan-out device in each of M network degrees;

directing signals to a plurality of M×

N wavelength selective switches for locally adding selected wavelengths, each M×

N wavelength selective switch for locally adding selected wavelengths having M outputs connected to an optical fan-in device in each of M network degrees; and

directing signals to an additional wavelength selective switch coupled to each network degree using an optical coupler.

17. The method of claim 16, further comprising activating M switching elements in each M×

N wavelength selective switch to effect switching between the M network degrees communicating with each wavelength selective switch.

18. The method of claim 17, wherein each of the M switching elements comprises a multidimensional micro-mirror array.