Simultaneous polarization splitter rotator

A device comprising:

• a substrate;
• a first optical waveguide disposed in the substrate on a first layer, the first optical waveguide arranged such that its position translates along an axis perpendicular to an axis extending between a first end of the first optical waveguide and a second end of the first optical waveguide;
• a second optical waveguide disposed in the substrate on a second layer, above the first layer, the second optical waveguide having a substantially rectangular shape and longitudinally arranged between the first end of the first optical waveguide and the second end of the first optical waveguide;
• and
• a third optical waveguide disposed in the substrate between the first optical waveguide and the second optical waveguide, the third optical waveguide extending in a same direction as the second optical waveguide,
• wherein a first gap between the first optical waveguide and the third optical waveguide is substantially smaller than a second gap between the second optical waveguide and the third optical waveguide.

A method comprising:

• presenting light, from an optical fiber, at a first end of a SiN optical waveguide disposed in a substrate;
• causing the light to interact with a curved Si optical waveguide disposed in the substrate at least partially underneath the SiN optical waveguide;
• causing the light to interact with a poly-silicon waveguide disposed between the SiN optical waveguide and the curved Si optical waveguide, wherein a first gap between the poly-silicon optical waveguide and the curved Si optical waveguide is substantially smaller than a second gap between the SiN optical waveguide and the poly-silicon optical waveguide;
• outputting a first optical signal on a second end of the SiN optical waveguide;
• and
• outputting a second optical signal at an end of the curved Si optical waveguide.