Compact and broadband polarization beam splitter based on a bridged hybrid plasmonic waveguide coupler on a thin-film lithium niobate

We propose a compact and broadband polarization beam splitter (PBS) based on a thin-film lithium niobate. The hybrid plasmonic waveguide (HPW) is used as a bridge in a three-waveguide coupler to achieve large birefringence. A degree of phase-matching is introduced for optimization. The proposed PBS exhibits a 125-nm bandwidth (1495-1620 nm) of polarization extinction ratio (PER) over 20 dB or an 85-nm bandwidth (1515-1600 nm) of PER over 25 dB, with a device length of only 81 mu m. An ultra-low insertion loss of 0.04 dB is achieved around the wavelength of 1550 nm. In addition, the proposed device exhibits high robustness of the fabrication tolerance. (c) 2024 Optica Publishing Group. All rights, including for text and data mining are reserved.