Systems and methods for photonic polarization beam splitters
An integrated photonic polarization beam splitter includes an optical coupler having an input port, a first output port, and a second output port. The optical coupler is operable to couple a portion of an input light beam at the input port into the first output port and another portion of the input light beam into the second output port. The integrated photonic polarization beam splitter also includes a first waveguide having a first linear polarizer embedded therein and coupled to the first output port of the optical coupler and a second waveguide having a second linear polarizer embedded therein and coupled to the second output port of the optical coupler.
1. An integrated photonic polarization beam splitter comprising:
an optical coupler having an input port, a first output port, and a second output port, wherein the optical coupler is operable to couple a portion of an input light beam at the input port into the first output port and another portion of the input light beam into the second output port;
a first waveguide having a first linear polarizer embedded therein and coupled to the first output port of the optical coupler; and
a second waveguide having a second linear polarizer embedded therein and coupled to the second output port of the optical coupler, wherein:
the second waveguide further comprises a 90-degree polarization rotator embedded therein;
the 90-degree polarization rotator is disposed between the second linear polarizer and the second output port of the optical coupler;
the first linear polarizer is characterized by a polarization direction; and
the second linear polarizer is characterized by the polarization direction.
2. The integrated photonic polarization beam splitter of claim 1 wherein the optical coupler comprises a multimode interference (MMI) coupler.
3. The integrated photonic polarization beam splitter of claim 1 wherein:
the first linear polarizer comprises a first plurality of structures disposed inside the first waveguide as a one-dimensional array; and
the second linear polarizer comprises a second plurality of structures disposed inside the second waveguide as a one-dimensional array;
wherein the first plurality of structures and the second plurality of structures are aligned in a plane substantially perpendicular to a direction of light propagation.
4. The integrated photonic polarization beam splitter of claim 3 wherein:
the first plurality of structures comprises nanostructures having a dimension less than a wavelength of the input light beam; and
the second plurality of structures comprises nanostructures having a dimension less than a wavelength of the input light beam.
5. The integrated photonic polarization beam splitter of claim 4 wherein a spacing between adjacent nanostructures is less than a wavelength of the input light beam.
6. The integrated photonic polarization beam splitter of claim 3 further comprising a substrate coupled to the optical coupler, the first waveguide, and the second waveguide, wherein at least one of the first plurality of structures or the second plurality of structures comprise a plurality of nanowires oriented substantially perpendicular to the substrate.
7. The integrated photonic polarization beam splitter of claim 3 further comprising a substrate coupled to the optical coupler, the first waveguide, and the second waveguide, wherein at least one of the first plurality of structures or the second plurality of structures comprise a plurality of nanowires oriented substantially parallel to the substrate.
8. The integrated photonic polarization beam splitter of claim 1 wherein the optical coupler comprises a 3 dB optical coupler.