Integrated optic polarization splitter based on total internal reflection from a birefringent polymer

An integrated optic polarization splitter with large fabrication tolerance and high reliability is required for optical signal processing in quantum-encrypted communication systems. A polarization splitter based on total internal reflection from a highly birefringent polymer—reactive mesogen—is proposed and demonstrated in this work. The device consists of a mode expander for reducing the wave vector distribution of the guided mode, and an interface with a large birefringence. Several polymers with suitable refractive indexes were used for fabricating the device. We obtained a polarization splitter with a low crosstalk (less than −30 dB), and a large fabrication tolerance.