Planar Waveguide Polarization Beam Splitter Based on Form Birefringence

A novel polarization beam splitter is designed on a slab waveguide platform where light is vertically confined. Planar lenses are formed to collimate and refocus a light beam by converting the phase front of the beam. A planar subwavelength grating of a wedge shape induces the form birefringence, where the transverse electric and transverse magnetic waves have different effective refractive indices and are steered to distinct directions. This design provides low insertion loss (<; 0.9 dB) and low crosstalk (<;-30 dB) for a bandwidth of 100 nm in a compact size, and can be realized by different material systems for easy fabrication and/or monolithic integration with other optical components.