Supercontinuum generation in a photonic crystal fiber with two zero-dispersion wavelengths tapered to normal dispersion at all wavelength

We numerically study supercontinuum generation in photonic crystal fibers with two zero-dispersion wavelengths, weakly tapered to have normal dispersion at all wavelengths after a certain distance. We pump with 15 fs pulses with milliwatt average power and show that two distinct smooth spectral parts are generated, with improved stability due to the normal dispersion. We characterize the two spectral parts and show how the 3 dB bandwidth, the center wavelength, and the power of the two parts depend on the taper parameters and the pump power.