Soft glass spiral photonic crystal fiber for large nonlinearity and high birefringence

This paper presents a soft glass spiral photonic crystal fiber with circular air holes for achieving high birefringence, large nonlinearity and large negative dispersion. The material used here for designing the fiber is soft glass (SF-57). A central defect air hole is being introduced in the core for achieving high birefringence and for different ellipticity ratios the effect of various optical properties of a photonic crystal fiber are studied. The structure proposed has a high birefringence in the order of 10–2, high nonlinearity of 5828 W–1km–1 and high negative dispersion of –1546.6 ps/nm•km at 0.850 μm. A numerical approach based on the finite element method is used for the design and simulation of the structure. Due to the optimization in the cladding air holes, the fiber can be used as polarization maintaining fibers, in dispersion compensation and other nonlinear applications.