Polarization-diverse integrated photonic switch with multi-layer waveguides

Abstract

Photonic integrated circuits (PICs) are provided and include polarization-diverse silicon photonic switches with multi-layer waveguides. The PICs of the present disclosure can be applied or used in a wide variety of fields including but not limited to fiber-optic communication, photonic computing, and light detection and ranging (LiDAR). The proposed PICs can include switches having two polarization-decomposed channels that propagate in closely spaced dual-channel waveguides, achieving polarization diverse operation without increasing the PIC area. By using two-layer waveguides and dual-channel micro-electro-mechanical-system (MEMS)-actuated switching elements to couple light from one layer to the other, the proposed scheme also eliminates waveguide crossings found in the prior arts.

Description

Abstract This invention provides a photonic integrated circuit (PIC) comprising a polarization diversity silicon photonic switch having multilayer waveguides. The PIC of this invention can be applied or used in various fields, including but not limited to fiber optic communication, photonic computing, and LiDAR (LiDAR). The proposed PIC can comprise a switch having two polarization-decomposition channels propagating in closely spaced dual-channel waveguides, thereby achieving polarization diversity operation without increasing the PIC area. By coupling light from one layer to another using a dual-layer waveguide and a dual-channel microelectromechanical system (MEMS) actuated switching element, the proposed scheme also eliminates the waveguide crossing found in the prior art.

Claims

CLAIMSWhat is claimed is:

1. A photonic integrated circuit (PIC) device, comprising: a substrate; one or more rows of horizontal waveguides disposed on a first layer of the substrate, each row of horizontal waveguides comprising a first horizontal waveguide and a second horizontal waveguide; one or more columns of vertical waveguides disposed on a second layer of the substrate, each column of vertical waveguides comprising a first vertical waveguide and a second vertical waveguide; one or more input polarization-insensitive couplers configured to couple external light to the one or more rows of horizontal waveguides; an input polarization splitter rotator (PSR) coupled to each of the one or more input polarization-insensitive couplers, each input PSR being configured to split the coupled light into the first and second horizontal waveguides in each of the one or more rows of horizontal waveguides; and a matrix of polarization-diverse photonic switches arranged at intersections between the one or more rows of horizontal waveguides and the one or more rows of vertical waveguides, the polarization-diverse photonic switches being actuatable to transfer light from the first and second horizontal waveguides for a given row of horizontal waveguides to first and second vertical waveguides of an intersecting column of vertical waveguides.

2. The PIC device of claim 1, further comprising an output PSR coupled to each of the one or more columns of vertical waveguides, each output PSR being configured to combine the light from the first and second vertical waveguides into a single output waveguide.

3. The PIC device of claim 2, further comprising one or more output polarizationinsensitive couplers coupled to each output waveguide.

4. The PIC device of claim 1, wherein the input PSRs are configured to split the input light into two orthogonal polarizations in two separate waveguides and rotate a polarization of one of the two separate waveguides to achieve the same polarization in the two separate waveguides.

5. The PIC device of claim 1, wherein the polarization-diverse photonic switches are micro-electro-mechanical-system (MEMS) switches.

6. The PIC device of claim 1, wherein the polarization-diverse photonic switches comprise first and second waveguide couplers disposed on a third layer of the substrate.

7. The PIC device of claim 6, wherein the third layer is above the first and second layers.

8. The PIC device of claim 6, wherein the third layer is between the first and second layers.

9. The PIC device of claim 6, wherein the first and second waveguide couplers are configured to be MEMS actuated to contact the first and second horizontal waveguides.

10. The PIC device of claim 6, wherein the first and second waveguide couplers are configured to be MEMS actuated to contact the first and second vertical waveguides.

11. The PIC device of claim 6, wherein the first and second horizontal waveguides are configured to be MEMS actuated to contact the first and second waveguide couplers.

12. The PIC device of claim 6, wherein the first and second vertical waveguides are configured to be MEMS actuated to contact the first and second waveguide couplers.

13. The PIC device of claim 1, wherein the polarization-diverse photonic switches comprise overlapped sections of the first and second horizontal waveguides with overlapped sections of the first and second vertical waveguides.

14. The PIC device of claim 13, wherein the overlapped sections comprise a number of turns or bends in each of the horizontal and vertical waveguides that allow for an overlap portion of the horizontal waveguides to align with an overlap portion of the vertical waveguides.

15. The PIC device of claim 14, wherein the overlap portion of the horizontal waveguides are parallel to the overlap portion of the vertical waveguides.

16. The PIC device of claim 15, wherein input and output ends of the horizontal waveguides are perpendicular to input and output ends of the vertical waveguides.

17. A photonic integrated circuit (PIC) device, comprising: a substrate; one or more rows of horizontal waveguides disposed on a first layer of the substrate, each row of horizontal waveguides comprising a transmit port, a receive port, a first horizontal waveguide, and a second horizontal waveguide; one or more columns of vertical waveguides disposed on a second layer of the substrate, each column of vertical waveguides comprising a transmit port, a receive port, a first vertical waveguide, and a second vertical waveguide; a transmit polarization splitter rotator (PSR) coupled to each of the transmit ports of the horizontal waveguides and to each of the transmit ports of the vertical waveguides, each transmit PSR being configured to split light into the first and second horizontal waveguides in each of the one or more rows of horizontal waveguides and into first and second vertical waveguides in each of the one or more rows of vertical waveguides; and a matrix of polarization-diverse photonic switches arranged at intersections between the one or more rows of horizontal waveguides and the one or more rows of vertical waveguides, the polarization-diverse photonic switches being actuatable to transfer light from the first and second horizontal waveguides corresponding to a given transmit port to first and second vertical waveguides corresponding to a paired receive port, and to transfer light from the first and second vertical waveguides corresponding to a given transmit port to first and second horizontal waveguides corresponding to a paired receive port.

18. The PIC device of claim 17, further comprising a receive PSR coupled to each of the receive ports of the horizontal waveguides and to each of the receive ports of the vertical waveguides , each receive PSR being configured to combine the light from the first and second vertical waveguides or the first and second horizontal waveguides into a single output waveguide.

19. The PIC device of claim 17, wherein the transmit PSRs are configured to split the light into two orthogonal polarizations in two separate waveguides and rotate a polarization of one of the two separate waveguides to achieve the same polarization in the two separate waveguides.

20. The PIC device of claim 17, wherein the polarization-diverse photonic switches are micro-electro-mechanical-system (MEMS) switches.

21. The PIC device of claim 17, wherein the polarization-diverse photonic switches comprise first and second waveguide couplers disposed on a third layer of the substrate, the first and second waveguide couplers being configured to couple the transmit port for a given row of horizontal waveguides with a receive port of a corresponding column of vertical waveguides.

22. The PIC device of claim 21, wherein the polarization-diverse photonic switches comprise third and fourth waveguide couplers disposed on the third layer of the substrate, the first and second waveguide couplers being configured to couple the transmit port for a given column of vertical waveguides with a receive port of a corresponding row of horizontal waveguides.

23. The PIC device of claims 21 or 22, wherein the third layer is above the first and second layers.

24. The PIC device of claims 21 or 22, wherein the third layer is between the first and second layers.

25. The PIC device of claims 21 or 22, wherein the first and second waveguide couplers are configured to be MEMS actuated to contact the first and second horizontal waveguides.

26. The PIC device of claims 21 or 22, wherein the first and second waveguide couplers are configured to be MEMS actuated to contact the first and second vertical waveguides.

27. The PIC device of claims 21 or 22, wherein the first and second horizontal waveguides are configured to be MEMS actuated to contact the first and second waveguides couplers.

28. The PIC device of claims 21 or 22, wherein the first and second vertical waveguides are configured to be MEMS actuated to contact the first and second waveguides couplers.

29. The PIC device of claim 17, wherein the polarization-diverse photonic switches comprise overlapped sections of the first and second horizontal waveguides with overlapped sections of the first and second vertical waveguides.

30. The PIC device of claim 29, wherein the overlapped sections comprise a number of turns or bends in each of the horizontal and vertical waveguides that allow for an overlap portion of the horizontal waveguides to align with an overlap portion of the vertical waveguides.

31. The PIC device of claim 30, wherein the overlap portion of the horizontal waveguides are parallel to the overlap portion of the vertical waveguides.

32. The PIC device of claim 31, wherein input and output ends of the horizontal waveguides are perpendicular to input and output ends of the vertical waveguides.

33. A method of directing light through a photonic integrated circuit (PIC), comprising: inputting light into a row of horizontal waveguides on a first layer of the PIC; splitting the light into first and second horizontal waveguides of the row of horizontal waveguides; controlling an array of micro-electro-mechanical-system (MEMS) photonic switches to transfer light from the first and second horizontal waveguides to first and second vertical waveguides of a selected column of vertical waveguides; and outputting the light from the selected column of vertical waveguides.

34. The method of claim 33, further comprising, before outputting the light, combining the light from the first and second vertical waveguides into a single output.

35. The method of claim 33, further comprising splitting the light into first and second horizontal waveguides in two orthogonal polarizations and then rotating a polarization of one of the first and second horizontal waveguides to achieve the same polarization in the first and second horizontal waveguides.

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