On-Chip Circular Polarization Splitter Using Silicon Photonic Nanoantenna Array

Abstract

Control and sorting of quantum states of photons through the manipulation of polarization and spatial modes of light in integrated photonic circuits contributes important applications in optical communications and quantum-optical systems. We design and demonstrate a novel structure for a silicon nanoantenna array that can split the circular polarization states and couple them to separate single-mode silicon waveguides. Implemented using a CMOS-compatible photonic fabrication process, the array can be monolithically integrated with other photonic components for chip-scale optical signal processing. We also show that the polarization sorting property of the nanoantenna array can be flexibly controlled (by adjusting design parameters at subwavelength scale) to split any two arbitrary orthogonal polarization states.