TWO LAYER POLARIZATION SPLITTER ROTATOR

A polarization splitter rotator includes a first lower waveguide and a second lower waveguide disposed on a first layer, the first lower waveguide and the second lower waveguide, in a first portion of the device, widening symmetrically as the first lower waveguide and the second lower waveguide extend from an input end of the device to an output end of the device, and, in a second portion of the device, at least the second lower waveguide widening further, asymmetrically, from the first lower waveguide, and a bus waveguide disposed on a second layer, above the first layer, at least partially overlapping portions of the first lower waveguide and the second lower waveguide.