MULTICAST OPTICAL SWITCH

• US 20130202297A1
• Filed: 02/07/2012
• Published: 08/08/2013
• Est. Priority Date: 02/07/2012
• Status: Active Grant

• Current Assignee: II-VI Delaware, Inc. (Coherent Corp.)
• Original Assignee: Massimo Martinelli
• Inventors: Sharma, Manish, Sun, Ruipeng, Garrett, Mark H., MARTINELLI, Massimo, Gurusami, Aravanan
• Granted Patent: US 8,731,403 B2
• Time in Patent Office: Days
• US Class Current: 398/49
• CPC Class Codes: G02B 2006/1215 Splitter
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• CPC Class Codes: G02B 6/2817 using reflective elements to split or combine optical signals
• CPC Class Codes: G02B 6/3512 the optical element being reflective, e.g. mirror
• CPC Class Codes: G02B 6/3518 the reflective optical element being an intrinsic part of a MEMS device, i.e. fabricated together with the MEMS device MEMS devices in general B81B; manufacture of MEM devices in general B81C; micromechanical devices controlling the direction of light G02B26/0833
• CPC Class Codes: G02B 6/3546 NxM switch, i.e. a regular array of switches elements of matrix type constellation

Abstract

A multicast optical switch includes a free-space optical assembly of discrete splitters, cylindrical optics, and a linear array of reflective switching devices, such as microelectromechanical systems (MEMS) mirrors, to provide low-loss, high-performance multicast switching in a compact configuration. The assembly of optical splitters may include multiple planar lightwave circuit splitters or a multi-reflection beam splitter that includes a linear array of partially reflecting mirrors, each of a different reflectivity.

Claims

1. An M×

N multicast switch, comprising;

M input ports, where M is greater than 1;

N output ports, where N is greater than 1;

M splitters, each configured to produce N split optical signals from an input optical signal received through one of the M input ports; and

a 1×

N array of mirrors each controllable to direct one of N split optical signals to one of the N output ports.

2. The multicast switch of claim 1, wherein each of the splitters comprises a planar lightwave circuit.

3. The multicast switch of claim 1, wherein each of the splitters comprises a linear array of partially-transmissive mirrors and each partially-transmissive mirror in the array has a different reflectivity.

4. The multicast switch of claim 1, wherein the M splitters are configured as a single assembly.

5. The multicast switch of claim 1, further comprising a planar lightwave circuit configured to receive the N optical signals directed by the mirrors and guide the N optical signals to the N output ports using N waveguides.

6. The multicast switch of claim 5, wherein each of the N waveguides comprises a variable optical attenuator.

7. The multicast switch of claim 1, wherein each mirror in the 1×

N array of mirrors is rotatable about a first axis to direct an optical signal received thereat to one of the N output ports.

8. The multicast switch of claim 7, wherein each mirror in the 1×

N array of mirrors is further rotatable about a second axis to enable hitless switching.

9. The multicast switch of claim 1, wherein the N split optical signals produced by one of the M splitters are of approximately equal intensity.

10. The multicast switch of claim 1, further comprising cylindrical optics disposed between the M splitters and the 1×

N array of mirrors and configured to focus light from the M splitters on each of the mirrors in a first plane and to produce an image with light from the M splitters on each of the mirrors in a second plane, the second plane being orthogonal to the first plane.

11. An M×

N multicast switch, comprising;

M input ports, where M is greater than 1;

N output ports, where N is greater than 1; and

M mirrors, each mirror associated with one of the input ports and controllable to direct an input optical signal from an associated input port to any one of the N output ports,

wherein, while one of the mirrors is controlled to switch the input optical signal directed at a first output port to be directed at a second output port, the input optical signal is optically decoupled from all of the output ports.

12. The multicast switch of claim 11, wherein, after said one of the mirrors has been controlled to switch the input optical signal directed at the first output port to be directed at the second output port, the input optical signal is optically coupled to the second output port.

13. The multicast switch of claim 12, wherein the controlled mirror is rotatable about a first axis to switch the input optical signal directed at the first output port to be directed at the second output port and is rotatable about a second axis to optically decouple the input optical signal from all of the output ports.

14. The multicast switch of claim 11, further comprising N splitters, each configured to produce M split optical signals from an input optical signal received through one of the N input ports.

15. The multicast switch of claim 14, wherein each of the splitters comprises a planar lightwave circuit.

16. The multicast switch of claim 14, wherein each of the splitters comprises a linear array of mirrors and each mirror in the array has a different reflectivity.

17. The multicast switch of claim 14, further comprising cylindrical optics disposed between the N splitters and the M mirrors and configured to focus light from the N splitters on each of the M mirrors in a first plane and to produce an image with light from the N splitters on each of the M mirrors in a second plane, the second plane being orthogonal to the first plane.

18. The multicast switch of claim 11, further comprising:

a liquid crystal pixel positioned in an optical path of the input optical signal for rotating a polarization of the input optical signal to optically decouple the input optical signal from all of the output ports.

19. The multicast switch of claim 18, further comprising:

a first beam steering assembly positioned between the input ports and the liquid crystal pixel for converting the input optical signal into a pair of parallel beams having the same polarization and for directing the parallel beams from the mirrors into one of the N output ports.

20. An M×

N multicast switch, comprising;

M input ports, where M is greater than 1;

N output ports, where N is greater than 1; and

a liquid-crystal on silicon (LCOS) panel having 1×

N beam steering elements, each beam steering element comprising multiple pixels whose phase can be controlled individually to direct an input optical signal from any one of the M input ports to one of the N output ports associated with the beam steering element.

21. The multicast switch of claim 20, further comprising M splitters, each configured to produce N split optical signals from an input optical signal received through one of the M input ports.

22. The multicast switch of claim 21, further comprising cylindrical optics disposed between the M splitters and the LCOS panel and configured to focus light from the M splitters on each of the beam steering elements in a first plane and to produce an image with light from the M splitters on each of the beam steering elements in a second plane, the second plane being orthogonal to the first plane.

23. The multicast switch of claim 22, further comprising:

a birefringent beam steering element configured to direct light having a first polarization state from each beam steering element of the LCOS panel into the output port associated with the beam steering element of the LCOS panel; and

an array of N liquid crystal elements disposed between the LCOS panel and the birefringent beam steering element, each liquid crystal element controllable to rotate the polarization of an input optical signal directed from one of the M input ports to one of the N output ports.

24. An M×

N multicast switch, comprising;

M input ports, where M is greater than 1;

N output ports, where N is greater than 1; and

N mirrors, each mirror controllable to direct an input optical signal from any one of the M input ports to one of the N output ports associated with the mirror,

wherein, while one of the mirrors is controlled to switch the input optical signal from a first input optical signal, which is received through a first of the M input ports, to a second input optical signal, which is received through a second of the M input ports, all input optical signals are first optically decoupled from an output port associated with the controlled mirror, and then the desired second input optical signal is coupled to the output port associated with the controlled mirror.

25. The multicast switch of claim 24, wherein the controlled mirror is rotatable about a first axis to switch the input optical signal from the first input optical signal to the second input optical signal and is rotatable about a second axis to optically decouple the first input optical signal from the output port associated with the controlled mirror.

26. The multicast switch of claim 24, further comprising M splitters, each configured to produce N split optical signals from an input optical signal received through one of the M input ports.

27. The multicast switch of claim 26, further comprising cylindrical optics disposed between the M splitters and the N mirrors and configured to focus light from the M splitters on each of the N mirrors in a first plane and to produce an image with light from the M splitters on each of the N mirrors in a second plane, the second plane being orthogonal to the first plane.

28. The multicast switch of claim 24, wherein each of the splitters comprises a planar lightwave circuit.

29. The multicast switch of claim 24, wherein each of the splitters comprises a linear array of mirrors and each mirror in the array has a different reflectivity.

30. The multicast switch of claim 24, further comprising a liquid crystal pixel positioned in an optical path of the first input optical signal for rotating a polarization of the first input optical signal to optically decouple the first input optical signal from the output port associated with the controlled mirror.