US Patent 10488590 Adiabatic polarization rotator-splitter

Various polarization rotator splitter (PRS) configurations are disclosed. In an example embodiment, a system includes a PRS that includes a silicon nitride (SiN) rib waveguide core that includes a rib and a ridge that extends vertically above the rib, the SiN rib waveguide core having a total height hSiN from a bottom of the rib to a top of the ridge, a rib height hrib from the bottom of the rib to a top of the rib, a rib width wrib, and a top width wSiN of the ridge. The rib width wrib varies along at least a portion of a length of the SiN rib waveguide core.