Investigation of optical nonlinearity in Photonic Crystal Fibers and supercontinuum generation

Photonic Crystal Fibers (PCFs) are a new class of optical waveguides which offer exceptional light guiding mechanism and deliver significantly improved performance compared to conventional optical fibers. In the present investigation, we propose an solid core PCF for three different values of air filling fraction. The proposed PCF is simulated by using COMSOL Multiphysics. The nonlinearity of proposed PCF is found to be varying with respect to its air filling fraction and a nonlinear coefficient of 148 W^-1Km^-1 is obtained for PCF with air filling fraction of 0.7. The variation of other parameters like effective refractive index, confinement loss and effective area with respect to wavelength and air filling fraction is also investigated. The supercontinuum spectrum is generated using the designed highly nonlinear fiber and the effect of pump power on the generated output spectrum is studied and results shows that the bandwidth of output spectrum increases with pump power provided its pulse width remains constant.