摘要：In this study, Octag.nal Photonic Crystal Fiber (O-PCF) structures are desig.ed for different air filling.fractions with fixed pitch leng.h of 2.2 μm. The lig.t propag.ting.characteristics of PCF structures such as effective refractive index, confinement loss, chromatic dispersion mode effective area and nonlinear coefficient are numerically analyzed. The simulation results show that the fibers have dispersion flattened, ultra-low loss hig.ly nonlinear nature in the waveleng.h reg.on 1.3 μm to 1.7 μm.