A compact integrated optic polarization splitter is highly anticipated for polarization multiplexed optical communications, dual polarization optical sensors, single photon quantum signal processing, etc. In this work, we propose and demonstrate a polarization mode extracting device using a highly birefringent crosslinked liquid crystal polymer, reactive mesogen. The device includes the birefringent material inserted into a Y-branch optical waveguide to extract the TE polarized mode. A polarization splitting ratio of 27 dB was obtained, and a crosstalk of less than -25 dB was maintained for a wavelength range of 1500~1600 nm. The device exhibited good thermal stability at 100 °C for 12 hours. The broadband operating characteristic is a unique advantage of the proposed mode extracting polarization splitter.