A polarization splitter includes a substrate, an asymmetric Y-shaped waveguide, and a pair of strip-shaped electrodes. The substrate is made of a birefringence crystal and includes a surface. The Y-shaped waveguide is formed into the surface and includes an input section for transmitting both transverse electric wave and transverse magnetic wave, a first branch for only transmitting the transverse electric wave, and a second branch for only transmitting the transverse magnetic wave. The first branch and the second branch branch off the input section. The electrodes are positioned on the surface, arranged at two opposite sides of the input section and substantially parallel with a central axis of the input section.