Design of triple-cladding photonic crystal fiber with near-zero flattened dispersion

In order to obtain the near-zero flattened dispersion at the wavelengths of 0.80 m and 1.55 m, at which the Ti: Sapphire femtosecond laser working wavelength and the optical communication window center, respectively, for the photon crystal fiber (PCF), we used the structural design of a triple-cladding PCF with the hexangular air-hole loop arrangement instead of the general mono-cladding one. Using the improved effective refraction index method on this triple-cladding PCF to perform the numerical simulation, we achieved satisfying results. The numerical simulation shows that the dispersion of this type of PCF changes apparently with small variations of the structural parameters, and therefore the structural designing, that leads to a near-zero(the dispersion range of 0.5 ps/(kmnm) and flattened (the dispersion slope range of 0.02 ps/(kmnm2) dispersion property at the wavelength ranges of 0.80 0.02 m and 1.550.15 m, respectively, is actualized through adjusting reasonably the PCF structural parameters. This result may play an important role on studying the optical communication system and femtosecond laser transmission characteristics in the PCFs to extend its applications.