Sudad S. Ahmed , Aseel I. Mahmood
In this study Endlessly Single Mode properties of index guiding Photonic Crystal Fiber for different core radii had been studied. This work is done by using Finite Element Analysis by using COMSOL MULTIPHYSICS simulation software, which is used to designed two index guiding photonic crystal fiber with six air holes rings one by omitting single air hole and the other by omitting five air holes to form fiber core. Each iteration has been done within range of pitch from 1μm to 10 μm and fixed wavelength of 1.55 μm. The influence of core diameter of photonic crystal fiber on endlessly single mode properties is done by calculation of V-parameter, the simulation results showed that core diameter limiting the endlessly single mode regime ;single mode operation can be extended to higher core diameter which is be very useful in different applications like polarization - maintaing , amplifiers, beam delivery and fiber laser.