Photonic Apparatus for Controlling Polarization

A photonic device, comprising:

• a lower cladding layer;
• a device layer disposed on the lower cladding layer, the device layer extending in a plane and having a thickness direction normal to the plane, the device layer comprising:
• a first waveguide formed from a first waveguide core bounded by cladding in the plane of the device layer, wherein the first waveguide supports TE and TM light within an operational wavelength range;
• and
• a second waveguide formed from a second waveguide core bounded by cladding in the plane of the device layer, wherein a portion of second waveguide core is disposed proximate to the first waveguide core in a coupling region to provide evanescent coupling of light within the operational wavelength range between the first waveguide core and the second waveguide core, wherein first waveguide core is formed from one of a first core structure or a second core structure, wherein the second waveguide core is formed from the other of the first core structure or the second core structure, wherein the first core structure is formed as a material having an index of refraction nM, wherein the second core structure is formed as alternating layers of a first material having a first index of refraction and second material having a second index of refraction that is different than the first material, the alternating layers arranged in a periodic structure with a periodicity along the thickness direction, the alternating layers providing an effective index of refraction for TE polarized light nTE and an effective index of refraction for TM polarized light nTM, wherein nTM<nM<nTE for light having wavelengths within the operational wavelength range, wherein one of TM or TE light is preferentially evanescently coupled between the first waveguide and the second waveguide.