Generation of wideband and flat supercontinuum over a 280-nm spectral range from a dispersion-flattened optical fiber with normal group-velocity dispersion

Aiming at wideband and Rat supercontinuum generation (SC) from optical fibe rs in the 1.55-mu m wavelength region, we study both experimentally and the oretically how SC spectra are influenced by group-velocity dispersion (GVD) of fibers. In the anomalous GVD region, since the peak power of pump pulse s is kept high during propagation through the fiber by the higher-order sol iton effect, the Raman effect has an adverse effect to Rat and wideband SC generation. In the zero GVD region, the interplay of the third-order disper sion (TOD) and the self-phase modulation splits the SC spectrum into two ma in components. On the other hand, in the normal GVD region, nevertheless th e SC spectrum broadens wider and smoother than those in anomalous and zero GVD regions, it is still asymmetric when TOD of the fiber can not be ignore d. From these results, we find that a dispersion-flattened fiber with norma l CVD is the most suitable for flat and wideband SC generation. A 280-nm wi de SC spectrum with the spectral-density fluctuation less than 10 dB is act ually generated from such a fiber.