New Insights of Polarization Beam Splitter Based on Sinusoidally Driven Directional Coupler

This paper studies on polarization beam splitter (PBS) in high-index-contrast waveguides based on sinusoidally driven directional coupler (SDDC), and offers new insights to realize compact and low-loss PBS with high fabrication tolerance. The PBS based on SDDC has advantage that power shift to an adjacent waveguide can be suppressed or totally banned by satisfying coherent destruction of tunneling (CDT) condition. However, in practical implementation, the PBS based on SDDC has trade-off relation between cross-talk of TE-like wave and loss of TM-like one. This paper investigates characteristics of the SDDC numerically, and shows possibility that cross-talk and loss can be suppressed, and small footprint can be achieved by position shift of DC-gap maintaining high fabrication tolerance.