Broad-band and extremely flat super-continuum generation via optical parametric gain extended spectrally by fourth-order dispersion in anomalous-dispersion-flattened fibers

Broad-band and extremely flat super-continuum (SC) generation phenomenon was found out in propagation of sub-100 fs and pJ optical pulse along very short anomalous-dispersion-flattened fibers (0.6~3.4 m). In contrast to the usual SC cases, fiber-optic anomalous-dispersion characteristics are essential. Results of numerical and experimental analyzes suggest that its origin stays in the broad-band optical parametric gain generation whose spectrum is extended by fourth-order dispersion characteristics. The remarkable features of SC spectra are (1) excellent static flatness of ±1 dB over 150 nm (or ±0.5 dB over 100 nm) and (2) asymmetric spectral expansion toward the shorter wavelength side overwhelming S-band