High extinction-ratio compact polarisation beam splitter on silicon.

A novel polarisation beam splitter (PBS) with a high extinction ratio in a broad band has been proposed and realised by cascading a bent directional coupler and a low-loss transverse-magnetic (TM)-pass polariser based on a subwavelength grating. The realised PBS has a footprint as small as 3 × 22.5 μm, a high extinction ratio (>20 dB) and a low excess loss (∼1 dB) are obtained over a broad band of ∼60 nm for both transverse-electric and TM polarisations. [ABSTRACT FROM AUTHOR]