Femtosecond Laser Inscribed Novel Polarization Beam Splitters Based on Tailored Waveguide Configurations

We report on a novel waveguide-based polarization beam splitter (PBS) fabricated by femtosecond (fs) laser in lithium niobate (LiNbO3) crystals. This monolithic PBS is composed of tailored waveguide configurations with different guiding properties in which linearly polarized light along extraordinary refractive index (ne) and ordinary index (no) can be well separated. At the wavelength of 1064 nm, polarization extinction ratio (PER) can reach to 16.60 dB and 16.18 dB for ne and no polarizations, with insertion loss (IL) of 3.86 dB and 4.15 dB respectively. Our work may pave a new way for designing high-performance PBS and creating compact polarization conversion systems in integrated photonics and quantum photonics.