HITLESS MxN WAVELENGTH SELECTIVE SWITCH

• US 20100061727A1
• Filed: 09/09/2009
• Published: 03/11/2010
• Est. Priority Date: 09/09/2008
• Status: Active Grant

• Current Assignee: Lumentum Operations, LLC (Lumentum Holdings Inc.)
• Original Assignee: JDS Uniphase Corporation (Lumentum Holdings Inc.)
• Inventors: Hennin, Stephen Robert de, Colbourne, Paul, McLaughlin, Sheldon, Wall, Pierre D.
• Granted Patent: US 8,233,794 B2
• Time in Patent Office: Days
• US Class Current: 398/48
• CPC Class Codes: H04J 14/0206 Express channels arrangements
• CPC Class Codes: H04J 14/0208 Interleaved arrangements
• 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: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 2011/003 using switches based on microelectro-mechanical systems [MEMS]
• CPC Class Codes: H04Q 2011/0052 Interconnection of switches

Abstract

A wavelength selective switch (WSS) based on an array of MEMS mirrors tiltable in 1-dimension about only one axis exhibits “hitting” or unwanted port connections during switching. Two WSS'"'"'s can be cascaded to create M×N switching functionality in a hitless manner by the inclusion of block ports at specified positions in one or both of the WSS'"'"'s. Greater use efficiency of ports can be achieved if quasi-hitless performance is acceptable.

Claims

1. An optical switching device, comprising:

a first wavelength selective switch stage comprising;

a plurality of input ports, each input port for receiving a respective DWDM signal;

a first common port for transmitting one of the respective DWDM signals;

a first adjustable reflector for selecting an optical path for a selected one of the respective DWDM signals between one of the plurality of input ports and the first common port; and

a first input block port disposed between the first common port and at least one of the input ports for providing the first adjustable reflector an interim position in which no signal is input to the first common port;

wherein the plurality of input ports, the first common port and the first input block port are collinear;

a second wavelength selective switch stage comprising;

a second common port optically coupled to the first common port for receiving the selected DWDM signal;

a plurality of output ports for transmitting the selected DWDM signal;

a second adjustable reflector for selecting an optical path for the selected DWDM signal between the second common port and one of the plurality of output ports; and

a switch controller for optically coupling the block port and the first common port when the second adjustable reflector is adjusted between settings;

wherein the plurality of output ports and the second common port are collinear.

2. An optical switching device according to claim 1, further comprising:

additional input block ports in the first wavelength selective switching stage, wherein each input port has one input block port adjacent thereto for providing the first adjustable reflector with a plurality of interim positions in which no signal is input to the first common port; and

a first output block port disposed between the second common port and at least one of the output ports for providing the second adjustable reflector an interim position in which no signal is directed to one of the output port;

wherein the plurality of output ports, the output block port and the second common port are collinear; and

wherein the switch controller optically couples the first output block port with the second common port when the first adjustable reflector is adjusted between settings.

3. An optical switching device in accordance with claim 1, further comprising:

additional output block ports in the second wavelength selective switching stage, wherein each output port has one output block port adjacent thereto for providing the second adjustable reflector with a plurality of interim positions in which no signal is input to the plurality of output ports;

wherein the plurality of output ports, the output block ports and the second common port are collinear; and

wherein the switch controller optically couples one of the output block ports with the second common port when the first adjustable reflector is adjusted between settings.

12. A method of operating the optical device of claim 1 comprising:

a) selecting an optical path with the first adjustable reflector between the first common port and the first input block port;

b) selecting an optical path with the second adjustable reflector between the second common port and a desired output port of the plurality of output ports; and

c) selecting an optical path with the first adjustable reflector between the first common port and a desired input port of the plurality of input ports.

13. A method of operating the optical device of claim 2 comprising:

a) selecting an optical path with the first adjustable reflector between the first common port and the block port adjacent to a current input port of the plurality of input ports;

b) selecting an optical path with the second adjustable reflector between the second common port and the output block port;

c) selecting an optical path with the first adjustable reflector between the first common port and the block port adjacent to the selected input port of the plurality of input ports;

d) selecting an optical path with the second adjustable reflector between the second common port and the desired output port of the plurality of output ports; and

e) selecting an optical path with the first adjustable reflector between the first common port and the desired input port of the plurality of input ports.

14. A method of operating the optical device of claim 3 comprising:

a) selecting an optical path with the second adjustable reflector between the first common port and the block port adjacent to a current output port of the plurality of output ports;

b) selecting an optical path with the first adjustable reflector between the first common port and the input block port;

c) selecting an optical path with the second adjustable reflector between the second common port and the block port adjacent to the desired output port of the plurality of output ports;

d) selecting an optical path with the first adjustable reflector between the first common port and the desired input port of the plurality of input ports; and

e) selecting an optical path with the second adjustable reflector between the second common port and the desired output port of the plurality of output ports.

4. An optical switching device comprising:

a first wavelength selective switch comprising;

a plurality of input ports, each input port for receiving a respective DWDM signal;

a first and a second common port for transmitting one of the respective DWDM signals; and

a first adjustable reflector for selecting an optical path for one of the respective DWDM signals between one of the plurality of input ports and one of the first and second common ports and;

wherein the plurality of input ports are disposed collinearly between the first and second common ports;

a second wavelength selective switch comprising;

a third common port optically coupled to the first common port for receiving one of the respective DWDM signals;

a first set of output ports adjacent to the third common port for transmitting one of the respective DWDM signals;

a fourth common port adjacent to the first set of output ports and optically coupled to the second common port for receiving one of the respective DWDM signals;

a second set of output ports adjacent to the fourth common port for transmitting one of the respective DWDM signals; and

a second adjustable reflector for simultaneously selecting an optical path for the respective DWDM signals between the third common port and one of the first set of output ports and between the fourth common port and one of the second set of output ports;

wherein the third and fourth common ports, the first set of output ports, and the second set of output ports are collinear; and

wherein the number of output ports in the first set and the second set is the same.

5. An optical switch comprising:

at least one input port for receiving a DWDM signal;

at least one output port for transmitting a modified DWDM signal;

at least one MEMS mirror for simultaneously providing an optical connection for two components of the DWDM signal between the at least one input port and the at least one output port.

6. The optical switch in accordance with claim 5, wherein:

the at least one input port comprises a plurality of input ports; and

the at least one output port comprises two adjacent output ports.

7. The optical switch in accordance with claim 5, wherein:

the at least one output port comprises a plurality of output ports; and

the at least one input port comprises two adjacent input ports.

8. An optical device for providing quasi hitless switching, comprising:

a first wavelength selective switch comprising;

a plurality of input ports, each input port for receiving a respective DWDM signal;

a first and a second common port for transmitting the respective DWDM signal; and

a first uniaxially tilting MEMS mirror for selecting an optical path for the respective DWDM signal between one of the first and second common ports and one of the plurality of input ports;

wherein the plurality of input ports are disposed collinearly between the first and second common ports;

a second wavelength selective switch comprising;

a third common port optically coupled to the first common port for receiving the respective DWDM signal;

a first set of output ports adjacent to the third common port for transmitting the respective DWDM signal;

a fourth common port adjacent to the first set of output ports and optically coupled to the second common port for receiving the respective DWDM signal;

a second set of output ports adjacent to the fourth common port for transmitting the respective DWDM signal; and

a second uniaxially tilting MEMS mirror for simultaneously selecting an optical path for the respective DWDM signals between the third common port and one of the first set of output ports and between the fourth common port and one of the second set of output ports;

wherein the third common port, the first set of output ports, the fourth common port and the second set of output ports are collinear.

9. An optical device for separating a DWDM signal containing odd- and even-numbered wavelength channels into a plurality of odd-numbered wavelength channels, a plurality of even-numbered wavelength channels, and a plurality of express wavelength channels, comprising:

a wavelength selective switch comprising;

a first input port for receiving the DWDM signal;

a first output port for transmitting the odd-numbered wavelength channels;

a second output port for transmitting the express wavelength channels;

a third output port for transmitting the even-numbered wavelength channels;

a uniaxially tilting MEMS mirror for each of the wavelength channels of the DWDM signal for selecting an optical path for the wavelength channel between the input port and one of the first, second, and third output ports;

wherein the input port and the first, second, and third output ports are collinear.

10. The optical device of claim 9, wherein the second output port is disposed between and adjacent to the first and third output ports.

11. The optical device of claim 9, wherein the wavelength channels contained in the DWDM signal have a 50 GHz spacing, the even-numbered wavelength channels have a 100 GHz spacing and the odd-numbered wavelength channels have a 100 GHz spacing.