An ultrashort polarization splitter based on dual-core photonic crystal fibers with gold wire has been proposed. Based on the beam propagation method with anisotropic perfectly matched layers, its polarization splitter coupling length, coupling length ratio, extinction ratio (ER), and bandwidth are numerically investigated. When the gold thread is filled in the fiber, the surface of the gold wire will produce the surface plasmon polaritons, which has certain influence on the beam propagation. A polarization splitter with shorter length and greater working bandwidth can be obtained by filling the gold wire. Numerical results demonstrate that the polarization splitter possesses extremely the length of 290 μm and high ER of −56.5 dB at the wavelength of 1.55 μm. Moreover, the polarization splitter is proposed to achieve ER better than −10 dB and a bandwidth of 19.2 nm.
We proposed a new structure of highly nonlinear low- dispersion photonic crystal fiber. Numerical results show that the dispersion variation is within ± 0.7 ps·km-1·nm-1 in the C band, and the corresponding nonlinear coefficient is 60.5 60.5 W-1·km-1. With the 6 W peak power of the input pulse, and PCF with 800 m length generates a SC with a spectrum ranging from 1500 to 1800 nm.