Design of all-normal dispersion photonic crystal fiber for high coherent broadband supercontinuum generation in the telecommunication window

An all-normal dispersion photonic crystal fiber with nearly zero flattened dispersion at 1550 nm is designed for generating high coherent broadband supercontinuum. It is found that an all normal dispersion photonic crystal fiber with nearly zero flattened dispersion at 1550 nm can be obtained by appropriately designing geometrical parameters and optimizing the index of the first ring of air-holes with filling different index liquid of the photonic crystal fiber. The results show that the optimized design photonic crystal fiber for pumping at 1550 nm is suitable for flat broadband and high coherent supercontinuum generation with only 4 kW input peak power in a 40 cm long of the photonic crystal fiber. It is also found the weaker the dispersion effect is, the more advantage to the high coherent broadband supercontinuum generation due to the self-phase modulation.