Broadband adiabatic polarization rotator-splitter based on a lithium niobate on insulator platform

Polarization rotator-splitters (PRSs) are crucial components for controlling the polarization states of light in classical and quantum communication systems. We design and experimentally demonstrate a broadband PRS based on the lithium niobate on insulator (LNOI) platform. Both the rotator and splitter sections are based on adiabatically tapered waveguide structures, and the whole device only requires a single etching step. We show efficient PRS operation over an experimentally measured bandwidth of 130 nm at telecom wavelengths, potentially as wide as 500 nm according to simulation prediction, with relatively low polarization crosstalks of similar to-10 dB. Our PRS is highly compatible with the design constraints and fabrication processes of common LNOI photonic devices, and it could become an important element in future LNOI photonic integrated circuits. (C) 2021 Chinese Laser Press

Automated summary

In this study, a broadband polarization rotator-splitter based on the lithium niobate on insulator platform was designed and experimentally demonstrated. The device showed efficient operation over a measured bandwidth of 130 nm at telecom wavelengths, with potential for even wider bandwidth according to simulation predictions. It exhibited low polarization crosstalk and high compatibility with common LNOI photonic devices, making it a potential key element in future LNOI photonic integrated circuits.