COMPACT MULTICAST SWITCHES, MXN SWITCHES AND MXN SPLITTERS

• US 20140294344A1
• Filed: 03/28/2013
• Published: 10/02/2014
• Est. Priority Date: 03/28/2013
• Status: Active Grant

• Current Assignee: Lumentum Operations, LLC (Lumentum Holdings Inc.)
• Original Assignee: Barthelemy Fondeur
• Inventors: FONDEUR, Barthelemy
• Granted Patent: US 9,363,581 B2
• Time in Patent Office: Days
• US Class Current: 385/17
• CPC Class Codes: G02B 6/3546 NxM switch, i.e. a regular array of switches elements of matrix type constellation
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 2011/0015 using splitting combining
• CPC Class Codes: H04Q 2011/0049 Crosstalk reduction; Noise; Power budget

Abstract

New architectures for multicast switches, and other optical switches and splitters, that have substantially reduced insertion loss, crosstalk and better overall optical performance in comparison to existing optical switches and splitters. Optimized waveguide mesh layouts are used to substantially reduce the number of waveguide crossings, which reduces insertion loss. The reduction in the number of crossings also reduces the complexity of the mesh and provides better crossing angles to reduce crosstalk and other issues. Instead of crossing all of the waveguides connected between splitter outputs and switch inputs, the waveguides are crossed in sets of waveguides.

Claims

1. An optical switching element comprising:

a first stage having M inputs and being adapted to split each input into N first stage outputs, wherein M and N are integers greater than one; and

a second stage connected to the first stage outputs and having N outputs, said second stage comprising at least first and second waveguide areas and at least first and second output switch areas, the first waveguide area comprising a plurality of waveguides connected between the first stage outputs and inputs of switches in the first output switch area, the second waveguide area comprising a plurality of waveguides connected between outputs of the switches in the first output switch area and inputs of switches in the second output switch area,

wherein the waveguides in the first and second waveguide areas cross other waveguides in the same waveguide area in respective sets of waveguides, each set comprising two or more waveguides.

2. The optical switching element of claim 1, wherein M is four and N is four and the waveguides in the first and second waveguide areas cross the other waveguides in the same waveguide areas in respective sets of four waveguides.

3. The optical switching element of claim 1, wherein M is eight and N is eight and said second stage further comprises a third waveguide area comprising a plurality of waveguides connected between outputs of the switches in the second output switch area and inputs of switches in a third output switch area, and

wherein the waveguides in the first, second and third waveguide areas cross other waveguides in the same waveguide area in respective sets of eight waveguides.

4. The optical switching element of claim 1, wherein M is four and N is eight and the waveguides in the first and second waveguide areas cross other waveguides in the same waveguide area in respective sets of eight waveguides.

5. The optical switching element of claim 1, wherein M is four and N is eight and said second stage further comprises a third waveguide area comprising a plurality of waveguides connected between outputs of the switches in the second output switch area and inputs of switches in a third output switch area, and

wherein the waveguides in the first, second and third waveguide areas cross other waveguides in the same waveguide area in respective sets of four waveguides.

6. The optical switching element of claim 1, wherein a number of waveguide crossings for a given waveguide path is at most (N−

1)×

log 2 (M).

7. An optical network element comprising M inputs and N outputs, said optical network element comprising:

at least one stage comprising a plurality of waveguide areas, wherein waveguides within each waveguide area cross other waveguides in the same waveguide area in sets of waveguides.

8. The optical network element of claim 7, wherein the waveguides within each waveguide area cross other waveguides in the same waveguide area in sets of N waveguides.

9. The optical network element of claim 7, wherein the waveguides within each waveguide area cross other waveguides in the same waveguide area in sets of M waveguides.

10. The optical network element of claim 7, wherein the optical element is an M×

N multicast switch.

11. The optical network element of claim 7, wherein the optical element is an M×

N optical switch.

12. The optical network element of claim 7, wherein the optical element is an M×

N splitter.

13. The optical network element of claim 7, wherein a number of waveguide crossings for a given waveguide path is at most (N−

1)×

log 2 (M).

14. An optical network element comprising:

a first stage having M inputs and a plurality of first stage outputs; and

a second stage connected to the plurality of first stage outputs and having N outputs, said second stage comprising first and second waveguide areas and first and second output areas, the first waveguide area comprising a plurality of waveguides connected between the first stage outputs and inputs of the first output area, the second waveguide area comprising a plurality of waveguides connected between outputs of the first output area and inputs of the second output,

wherein waveguide crossings occur in sets of waveguides comprising more than 1 waveguide.

15. The optical switching element of claim 14, wherein M is four and N is four and the waveguides in the first and second waveguide areas cross other waveguides in the same waveguide area in respective sets of four waveguides.

16. The optical switching element of claim 14, wherein M is eight and N is eight and said second stage further comprises a third waveguide area comprising a plurality of waveguides connected between outputs of the second output area and inputs of a third output area, and the waveguides in the first, second and third waveguide areas cross other waveguides in the same waveguide area in respective sets of eight waveguides.

17. The optical switching element of claim 14, wherein M is four and N is eight and the waveguides in the first and second waveguide areas cross other waveguides in the same waveguide area in respective sets of eight waveguides.

18. The optical switching element of claim 14, wherein M is four and N is eight and said second stage further comprises a third waveguide area comprising a plurality of waveguides connected between outputs of the second output area and inputs of a third output area, and the waveguides in the first, second and third waveguide areas cross other waveguides in the same waveguide area in respective sets of four waveguides.

19. The optical switching element of claim 14, wherein a number of waveguide crossings for a given waveguide path is at most (N−

1)×

log 2 (M).