Patent ID: 8855449

Claim:
An apparatus comprising: an input port to receive light from a fiber; a first and a second output port; and a polarization converter and splitter coupling the input port and the first and second output ports configured such that: light having a first input mode polarization state is output via the first output port as a first output light having a first pure polarization state; and light having a second input mode polarization state, orthogonal to the first input mode polarization state, is output via the second output port as a second output light having the first pure polarization state and orthogonal in amplitude or phase to the first output light; wherein the polarization converter and splitter comprises: an input waveguide segment to receive light from the input port; a first output waveguide segment to receive light from the input waveguide segment and to output light to the first output port; a second output waveguide segment to receive light from the input waveguide segment and to output light to the second output port; and a taper section having a changing width increasing along a length to adiabatically convert the light to be output from the second input mode polarization state to the first pure polarization state; and wherein the waveguides of the polarization converter and splitter are disposed for an anti-crossing to occur within the taper section between a mode in the first pure polarization state and a mode in an orthogonal second pure polarization state.