We investigate the coupling characteristics in dual-core photonic crystal fibers (PCFs) with elliptical air holes and their applications in the construction of polarization splitters by use of a full-vector beam propagation method. The numerical simulation results indicate the possibility of realizing a polarization splitter with an extinction ratio better than -20 dB at 1.55 microns and a total length of only 1.651 mm. It is also revealed that the total length of the polarization splitters can be further reduced by properly doping the core regions of the PCFs.