Experimental study and numerical analysis of femtosecond pulse propagation and supercontinuum generation in highly nonlinear photonic crystal fiber

Abstract

Femtosecond laser pulse propagation and supercontinuum generation in a highly nonlinear photonic crystal fiber is investigated experimentally and numerically. Consistent results of continuum generation measured and calculated for 790, 800, and 820 nm pump wavelengths are presented. It is shown that when the pump wavelength overlaps with the zero-dispersion wavelength self-phase modulation and third-order dispersion play an important role, and the oscillation structure appears in the temporal waveform of the propagating pulses, whereas in anomalous dispersion region, the formation and the red-shift of solitons are evident, and the self phase modulation plays a dominant role only in the initial stage. Further spectral broadening is due to solitons self-frequency shift, fission of higher-order solitons and four-wave mixing. It is also found that four-wave mixing occurs more easily in anomalous dispersion region than at the zero-dispersion wavelength.