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CN-121995576-A - Polarization beam splitter-rotator

CN121995576ACN 121995576 ACN121995576 ACN 121995576ACN-121995576-A

Abstract

The present disclosure relates to polarizing beam splitter-rotators. Photonic Integrated Circuits (PICs) may include polarization rotators. The polarization rotator may include a first waveguide layer including a first set of waveguides. At least one waveguide of the first set of waveguides may be a segmented waveguide. The polarization rotator may include a second waveguide layer including a second set of waveguides. The refractive index of the core material of the second set of waveguides may be less than the refractive index of the core material of the first set of waveguides.

Inventors

  • M. B. Mia
  • K. A. Macquarie
  • E. Timurdogen

Assignees

  • 朗美通经营有限责任公司

Dates

Publication Date
20260508
Application Date
20250928
Priority Date
20241220

Claims (20)

  1. 1. A photonic integrated circuit PIC comprising a polarization rotator, the polarization rotator comprising: a first waveguide layer comprising a first set of waveguides, wherein at least one waveguide of the first set of waveguides is a segmented waveguide, and A second waveguide layer comprising a second set of waveguides, Wherein the refractive index of the core material of the second set of waveguides is less than the refractive index of the core material of the first set of waveguides.
  2. 2. The PIC of claim 1, wherein the first waveguide layer is a silicon Si waveguide layer and the second waveguide layer is a silicon nitride SiN x waveguide layer.
  3. 3. The PIC of claim 1, wherein the segmented waveguide has a periodicity of less than about 500 nanometers.
  4. 4. The PIC of claim 1, wherein the segmented waveguide has a refractive index of less than about Of (3), wherein Is the operable wavelength of the polarization rotator, and n is the refractive index of the segmented waveguide.
  5. 5. The PIC of claim 1, wherein a fill rate associated with the first set of waveguides is in a range of about 0.1 to about 0.8.
  6. 6. The PIC of claim 1, wherein the first waveguide layer is on the second waveguide layer.
  7. 7. The PIC of claim 1, wherein the second waveguide layer is on the first waveguide layer.
  8. 8. The PIC of claim 1, wherein one or more waveguide segments of the segmented waveguide have a shape that is elongated with a longer dimension oriented at 90 degrees relative to a propagation direction.
  9. 9. The PIC of claim 1, wherein one or more waveguide segments of the segmented waveguide have a shape that is elongated with a longer dimension oriented at an arbitrary angle relative to a propagation direction.
  10. 10. The PIC of claim 1, wherein the polarization rotator comprises a spacer region between the first waveguide layer and the second waveguide layer.
  11. 11. The PIC of claim 1, wherein the first set of waveguides includes four curved waveguide sections that taper exponentially.
  12. 12. The PIC of claim 1, wherein at least one waveguide of the second set of waveguides comprises a segmented waveguide.
  13. 13. The PIC of claim 12, wherein the segmented waveguide has a periodicity of less than about 900 nanometers.
  14. 14. The PIC of claim 12, wherein the segmented waveguide has a refractive index of less than about Of (3), wherein Is the operable wavelength of the polarization rotator, and n is the effective refractive index of the polarization rotator.
  15. 15. The PIC of claim 1, wherein the first set of waveguides includes a first waveguide and a second waveguide, the first waveguide and the second waveguide being symmetrically arranged with respect to a centerline of one of the second set of waveguides.
  16. 16. The PIC of claim 1, wherein the first set of waveguides comprises a first waveguide and a second waveguide, wherein a spacing between the first waveguide and the second waveguide is in a range of about 0.3 micrometers (μιη) to about 2.5 μιη along a taper length associated with the first waveguide and the second waveguide.
  17. 17. The PIC of claim 1, wherein a width of a waveguide in the first set of waveguides is less than about 450 nanometers.
  18. 18. The PIC of claim 1, wherein the PIC further comprises a mode beam splitter, wherein the polarization rotator is optically connected to the mode beam splitter.
  19. 19. The PIC of claim 18, wherein the mode splitter comprises one or more segmented waveguides.
  20. 20. The PIC of claim 18, wherein the mode splitter comprises a first tapered waveguide and a second tapered waveguide.

Description

Polarization beam splitter-rotator Cross Reference to Related Applications This patent application claims priority from U.S. provisional patent application No. 63/717,659, filed ON 7/11/2024, and entitled "MULTI-core metamaterial ENHANCED ON-chip polarizing beam splitter-rotator (MULTI-CORE METAMATERIAL-ENHANCED ON-CHIP POLARIZATION SPLITTER-ROTATOR)". The disclosure of this prior application of this patent application is considered to be part of the present patent application and is incorporated by reference. Technical Field The present disclosure relates generally to polarization beam splitter-rotators (PSRs) and PSRs comprising one or more segmented waveguides. Background A polarizing beam splitter-rotator (PSR) is a passive photonic component that splits polarized light into two separate paths based on the polarization state of the polarized light. The PSR may operate with Transverse Electric (TE) or Transverse Magnetic (TM) polarized light. In operation of the PSR, one polarized light input changes to its orthogonal polarization state at the output of one path, while the other polarized light input maintains its original state at the output of the other path. For example, the PSR may convert TM polarized light to TE polarized light and maintain the TE polarized light in its original state. This capability improves the manipulation and management of light within Photonic Integrated Circuits (PICs), which contributes to improvements in devices requiring polarization insensitivity, the efficiency of coherent optical transceivers, and on-chip optical communication systems, for example. Disclosure of Invention In some embodiments, a Photonic Integrated Circuit (PIC) including a polarization rotator includes a first waveguide layer including a first set of waveguides, wherein at least one waveguide of the first set of waveguides is a segmented waveguide, and a second waveguide layer including a second set of waveguides, wherein a refractive index of a core material of the second set of waveguides is less than a refractive index of a core material of the first set of waveguides. In some embodiments, a PIC comprising a polarization beam splitter-rotator comprises a polarization rotator comprising a first set of waveguides in a first waveguide layer, wherein at least one of the first set of waveguides is a segmented waveguide, and a second set of waveguides in a second waveguide layer, wherein a refractive index of a core material of the second set of waveguides is less than a refractive index of a core material of the first set of waveguides, and a polarization beam splitter and a mode beam splitter, wherein the polarization beam splitter is optically connected to the mode beam splitter. In some embodiments, a PIC including a polarization rotator includes a silicon (Si) waveguide layer including a set of segmented Si waveguides, wherein a periodicity of segmented Si waveguides in the set of segmented Si waveguides is less than about 900 nanometers (nm), and wherein a fill ratio of the segmented Si waveguides is in a range of about 0.1 to about 0.8, and a silicon nitride SiN x waveguide layer including a set of SiN x waveguides. Drawings Fig. 1 is a schematic diagram illustrating an example embodiment of a PSR including one or more segmented waveguides described herein. Fig. 2 illustrates an example of calculated dielectric constants with respect to the filling ratios of various wavelengths. FIG. 3 is a graph illustrating the effective refractive indices of the fundamental transverse electric (TE 0) mode, the fundamental transverse magnetic (TM 0) mode, and the first order TE (TE 1) mode of the exemplary embodiment of PSR with different spacer region heights described herein. Fig. 4-7 are graphs illustrating field distributions determined by the effective refractive index shown in fig. 3. Fig. 8 illustrates eigenmode expansion for excitation of TE 0 and TM 0 modes in an example embodiment of the PSR described herein. Fig. 9 shows the effect of fill rate on power constraint in the waveguides of the PSR described herein as a function of spacer height. Fig. 10 shows the effect of fill rate on power constraints in the waveguide of the PSR described herein for a particular spacer height with another change in fill rate. Fig. 11 illustrates the effective refractive index along the rotated section of the PSR described herein for different width values of the segmented waveguide. Fig. 12 is a graph illustrating coupling factors associated with the PSR described herein as the spacing between the waveguides of the PSR changes. Fig. 13 illustrates an example of the effective refractive indices of different modes supported by the waveguides of the PSR described herein along the mode splitter of the PSR. Fig. 14-17 are schematic diagrams illustrating field distributions determined by the effective refractive index, which demonstrate how modes are distributed along the beam splitting length of the PSR described herein. Fig.