Cavity dispersion management in continuous-wave supercontinuum generation

Supercontinuum generation using continuous-wave pumping is usually obtained by pumping a suitable fiber with a high-power fiber laser. Whereas many studies have concentrated in optimizing the dispersion characteristics of the nonlinear medium (the fiber) used to obtain the spectral broadening, very few have actually concentrated in optimizing the pump laser characteristics, and in particular, the dispersion in the cavity. In this paper we experimentally demonstrate that the fiber laser cavity dispersion has a strong influence in Raman fiber laser-pumped continuous-wave supercontinuum generation. We show that anomalous dispersion in the cavity favors spectral broadening over normal dispersion, since large, high-contrast intensity noise appears at the output of the laser. Additionally, we find that there is an optimum value of chromatic dispersion coefficient to obtain the most efficient broadening. (C) 2009 Optical Society of America