Shared, Colorless Add/Drop Configuration for a ROADM Network using MxN Wavelength Swithches

• US 20100202778A1
• Filed: 02/11/2009
• Published: 08/12/2010
• Est. Priority Date: 02/11/2009
• Status: Active Grant

• 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
• Granted Patent: US 8,111,995 B2
• Time in Patent Office: Days
• 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 (ROADM) transport network having at least one optical transponder, comprising:

a plurality of optical fan-out devices, each arranged to receive an input signal from a network degree and coupled to at least one of 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-in devices comprising at least one wavelength selective switch, the optical fan-out devices and optical fan-in devices being connected so as to enable signals input from each of the 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; and

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.

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 switching element comprises a multidimensional micro-mirror array (MEMS).

6. The system of claim 5, wherein each MEMS comprises a plurality of mirror elements rotatable around first and second orthogonal axes for independent wavelength routing.

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

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

8. The system of claim 7, wherein the dispersive element in each M×

N WSS further comprises at least one arrayed waveguide grating (AWG).

9. The system of claim 8, wherein each M×

N WSS further comprises an M plurality of AWGs, and an additional two-dimensional switching element such that at least one of the focusing optics is disposed between the M switching elements and the additional two-dimensional switching element.

10. The system of claim 1, further comprising an optical coupler for adding an additional WSS to each network degree.

11. A system for dynamically adding/dropping wavelengths in a reconfigurable optical add-drop multiplexer (ROADM) transport network having at least one optical transponder, comprising:

a plurality of optical fan-out devices, each arranged to receive an input signal from a network degree and coupled to at least one of 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-in devices comprising at least one wavelength selective switch, the optical fan-out devices and optical fan-in devices being connected so as to enable signals input from each of the 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; and

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,

wherein each M×

N wavelength selective switch comprises M switching elements.

12. The system of claim 11, wherein each switching element comprises a multidimensional micro-mirror array (MEMS).

13. The system of claim 12, wherein each MEMS comprises a plurality of mirror elements rotatable around first and second orthogonal axes for independent wavelength routing.

14. The system of claim 12, wherein each M×

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

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

N WSS further comprises at least one arrayed waveguide grating (AWG).

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

N WSS further comprises an M plurality of AWGs, and an additional two-dimensional switching element such that at least one of the focusing optics is disposed between the M switching elements and the additional two-dimensional switching element.

17. The system of claim 12, further comprising an optical coupler for adding an additional WSS to each network degree.

18. A method for dynamically adding/dropping wavelengths in a reconfigurable optical add-drop multiplexer (ROADM) transport network including a plurality of optical fan-out devices, each arranged to receive an input signal from a network degree and coupled to at least one of 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-in devices comprising at least one wavelength selective switch, the optical fan-out devices and optical fan-in devices being connected so as to enable signals input from each of the 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; and

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.

19. The method of claim 18, 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.

20. The method of claim 19, wherein each of the M switching elements comprises a multidimensional micro-mirror array (MEMS).