Ultrashort polarization beam splitter based on liquid-filled dual-core photonic crystal fiber

An ultrashort polarization beam splitter (PBS) is proposed based on liquid-filled dual-core photonic crystal fiber (DCPCF). The two cores of DCPCF are formed by two side elliptical holes and a central circular hole in the horizontal direction. The properties of the PBS are analyzed first with a non-filled DCPCF by the finite element method. Then, the performances of the PBS are discussed when the DCPCF is filled with liquids in the central hole. As a result, an ultrashort PBS is realized with a length of 78 μm when glycerol solution with a concentration of 37% is filled in the central hole. In this case, an extinction ratio of 87 dB is obtained at 1550 nm wavelength. The significantly short device shows a great advantage when being integrated in ultra-compact optical systems.