Modulation instability induced supercontinuum generation in defective core photonic crystal fiber

摘要

We theoretically investigate effect of defect on modulation instability induced supercontinuum generation in a defective core photonic crystal fiber. We highlight the advantage of defective air hole in enhancing the photonic crystal fiber nonlinearity. For further enhancement in the nonlinearity of the defective core fiber, we change the d/? ratio of the fiber. The effect of change in nonlinearity with alteration in defective air hole size and d/? ratio has been studied through a well-known nonlinear phenomenon known as modulation instability. The modulation instability gain is found to be increasing with increase in defective air hole size and decrease in d/? ratio. As the modulation instability causes spectral broadening by pulse breaking in the fiber through noise amplification, we have also studied the resulting spectral broadening known as modulation instability induced supercontinuum generation. Similitude to the effect of defect and d/? ratio on modulation instability, very broad spectra obtained at fiber output and which is further enhanced through increasing the defective air hole radius and decreasing d/? ratio.